Add support for authentication using an Azure.Core.TokenCredential (#197)

* support authentication using token credentials.

* address PR feedback

* use overload instead of optional argument to be compatible without requiring recompilation

* address PR feedback

* address PR feedback

DurableTask.Netherite.sln

@@ -36,6 +36,10 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LoadGeneratorApp", "test\Lo
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "HelloDTFx", "samples\HelloDTFx\HelloDTFx\HelloDTFx.csproj", "{EC293D85-91E3-4F78-8B1E-2C691315CE96}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "TokenCredentialDF", "samples\TokenCredentialDF\TokenCredentialDF.csproj", "{B99AB043-47DC-467C-93CB-D6C69D3B1AD4}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "TokenCredentialDTFx", "samples\TokenCredentialDTFx\TokenCredentialDTFx.csproj", "{FBFF0814-E6C0-489A-ACCF-9D0699219621}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -78,6 +82,14 @@ Global
 		{EC293D85-91E3-4F78-8B1E-2C691315CE96}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{EC293D85-91E3-4F78-8B1E-2C691315CE96}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{EC293D85-91E3-4F78-8B1E-2C691315CE96}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B99AB043-47DC-467C-93CB-D6C69D3B1AD4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B99AB043-47DC-467C-93CB-D6C69D3B1AD4}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B99AB043-47DC-467C-93CB-D6C69D3B1AD4}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B99AB043-47DC-467C-93CB-D6C69D3B1AD4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{FBFF0814-E6C0-489A-ACCF-9D0699219621}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{FBFF0814-E6C0-489A-ACCF-9D0699219621}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{FBFF0814-E6C0-489A-ACCF-9D0699219621}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{FBFF0814-E6C0-489A-ACCF-9D0699219621}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -92,6 +104,8 @@ Global
 		{2F4D331C-62E4-47E8-852E-163166944DF8} = {4A7226CF-57BF-4CA3-A4AC-91A398A1D84B}
 		{78B360B8-3A41-4DC0-A300-94A0FABC1FB0} = {4A7226CF-57BF-4CA3-A4AC-91A398A1D84B}
 		{EC293D85-91E3-4F78-8B1E-2C691315CE96} = {AB958467-9236-402E-833C-B8DE4841AB9F}
+		{B99AB043-47DC-467C-93CB-D6C69D3B1AD4} = {AB958467-9236-402E-833C-B8DE4841AB9F}
+		{FBFF0814-E6C0-489A-ACCF-9D0699219621} = {AB958467-9236-402E-833C-B8DE4841AB9F}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {238A9613-5411-41CF-BDEC-168CCD5C03FB}

samples/TokenCredentialDF/FunctionsStartup.cs

@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+// Reference: https://docs.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection
+[assembly: Microsoft.Azure.Functions.Extensions.DependencyInjection.FunctionsStartup(typeof(TokenCredentialDF.Startup))]
+namespace TokenCredentialDF
+{
+    using System;
+    using Azure.Identity;
+    using DurableTask.Netherite;
+    using DurableTask.Netherite.AzureFunctions;
+    using Microsoft.Azure.Functions.Extensions.DependencyInjection;
+    using Microsoft.Azure.WebJobs;
+    using Microsoft.Extensions.DependencyInjection;
+    using Microsoft.Extensions.DependencyInjection.Extensions;
+    using Microsoft.Extensions.Logging;
+
+    public class Startup : FunctionsStartup
+    {
+        public class MyConnectionResolver : CredentialBasedConnectionNameResolver
+        {
+            readonly INameResolver nameResolver;
+
+            public MyConnectionResolver(INameResolver nameResolver) : base(new DefaultAzureCredential()) 
+            {
+                this.nameResolver = nameResolver;
+            }
+            
+            string Resolve(string name)  =>
+                this.nameResolver.Resolve(name) 
+                ?? Environment.GetEnvironmentVariable(name)
+                ?? throw new InvalidOperationException($"missing configuration setting '{name}'");
+
+            public override string GetStorageAccountName(string connectionName) => this.Resolve($"{connectionName}__accountName");
+
+            public override string GetEventHubsNamespaceName(string connectionName) => this.Resolve($"{connectionName}__eventHubsNamespaceName");
+        }
+
+        public override void Configure(IFunctionsHostBuilder builder)
+        {
+            builder.Services.AddSingleton<DurableTask.Netherite.ConnectionResolver, MyConnectionResolver>();
+        }
+    }
+}

samples/TokenCredentialDF/Hello.cs

@@ -0,0 +1,57 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace TokenCredentialDF
+{
+    using System;
+    using System.Threading.Tasks;
+    using Microsoft.AspNetCore.Mvc;
+    using Microsoft.Azure.WebJobs;
+    using Microsoft.Azure.WebJobs.Extensions.Http;
+    using Microsoft.AspNetCore.Http;
+    using Microsoft.Azure.WebJobs.Extensions.DurableTask;
+    using System.Collections.Generic;
+    using System.Net;
+
+    /// <summary>
+    /// A simple Http Trigger that is useful for testing whether the service has started correctly and can execute orchestrations.
+    /// </summary>
+    public static class Hello
+    {
+
+        [FunctionName(nameof(Hello))]
+        public async static Task<IActionResult> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", Route = "hello")] HttpRequest req,
+            [DurableClient] IDurableClient client)
+        {
+            try
+            {
+                string orchestrationInstanceId = await client.StartNewAsync(nameof(HelloSequence));
+                TimeSpan timeout = TimeSpan.FromSeconds(30);
+                return await client.WaitForCompletionOrCreateCheckStatusResponseAsync(req, orchestrationInstanceId, timeout);
+            }
+            catch (Exception e)
+            {
+                return new ObjectResult($"exception: {e}") { StatusCode = (int)HttpStatusCode.InternalServerError };
+            }         
+        }
+
+        [FunctionName(nameof(HelloSequence))]
+        public static async Task<List<string>> HelloSequence([OrchestrationTrigger] IDurableOrchestrationContext context)
+        {
+            var result = new List<string>
+            {
+                await context.CallActivityAsync<string>(nameof(SayHello), "Tokyo"),
+                await context.CallActivityAsync<string>(nameof(SayHello), "Seattle"),
+                await context.CallActivityAsync<string>(nameof(SayHello), "London")
+            };
+            return result;
+        }
+
+        [FunctionName(nameof(SayHello))]
+        public static Task<string> SayHello([ActivityTrigger] IDurableActivityContext context)
+        {
+            return Task.FromResult(context.GetInput<string>());
+        }
+    }
+}

samples/TokenCredentialDF/Ping.cs

@@ -0,0 +1,42 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace TokenCredentialDF
+{
+    using System;
+    using System.IO;
+    using System.Threading.Tasks;
+    using Microsoft.AspNetCore.Mvc;
+    using Microsoft.Azure.WebJobs;
+    using Microsoft.Azure.WebJobs.Extensions.Http;
+    using Microsoft.AspNetCore.Http;
+    using Microsoft.Extensions.Logging;
+    using Microsoft.Azure.WebJobs.Extensions.DurableTask;
+    using System.Net;
+
+    /// <summary>
+    /// A simple Http Trigger that is useful for testing whether the functions host has started correctly.
+    /// </summary>
+    public static class Ping
+    {
+        [FunctionName(nameof(Ping))]
+        public static async Task<IActionResult> Run(
+            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
+            [DurableClient(ConnectionName = "MyConnection")] IDurableClient client,
+            ILogger log)
+        {
+            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
+            log.LogInformation("C# HTTP trigger function processed a request.");
+            var is64bit = Environment.Is64BitProcess;
+
+            try
+            {
+                return new OkObjectResult($"Hello from {client} ({(is64bit ? "x64" : "x32")})\n");
+            }
+            catch (Exception e)
+            {
+                return new ObjectResult($"exception: {e}") { StatusCode = (int)HttpStatusCode.InternalServerError };
+            }
+        }
+    }
+}

samples/TokenCredentialDF/README.md

@@ -0,0 +1,24 @@
+# Token Credential Sample
+
+This sample demonstrates how to configure a custom connection resolver when using Netherite in an Azure Functions application.
+
+## Why you may want to use a custom resolver
+
+A custom connection resolver is appropriate if you want more control over how connection names are resolved to connection information. For example:
+
+- It allows you to construct your own Token Credential.
+- It allows you to use your own configuration logic for resolving connection names, as opposed to following the default mechanism defined by Azure Functions.
+
+For this sample, we use the default Azure Identity credential as provided by the Azure.Identity package.
+
+## Configuration Prerequisites
+
+Before running this sample, you must
+
+1. Create a new Azure Storage account, or reuse an existing one
+2. Create a new Azure Event Hubs namespace, or reuse an existing one (that is not currently in use)
+3. Make sure you have [Storage Blob Data Contributor](https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#storage-blob-data-contributor) and [Storage Table Data Contributor](https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#storage-table-data-contributor) permissions for the storage account.
+4. Make sure you have [Azure Event Hubs Data Owner](https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#azure-event-hubs-data-owner) permission for the event hubs namespace.
+5. Set `MyConnection__accountName` to contain the name of the storage account, using an environment variable or a function app configuration setting,
+6. Set `MyConnection__eventHubsNamespaceName` to contain the name of the Event Hubs namespace, using an environment variable or a function app configuration setting.
+

samples/TokenCredentialDF/TokenCredentialDF.csproj

@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="4.1.3" />
+	<PackageReference Include="Microsoft.Azure.Functions.Extensions" Version="1.1.0" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\DurableTask.Netherite.AzureFunctions\DurableTask.Netherite.AzureFunctions.csproj" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Update="host.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+</Project>

samples/TokenCredentialDF/host.json

@@ -0,0 +1,29 @@
+{
+  "version": "2.0",
+  "logging": {
+    "logLevel": {
+      "DurableTask.Netherite": "Information",
+      "DurableTask.Netherite.FasterStorage": "Information",
+      "DurableTask.Netherite.EventHubsTransport": "Information"
+    },
+    "applicationInsights": {
+      "sampling": {
+        "isEnabled": false
+      }
+    }
+  },
+  "extensions": {
+    "http": {
+      "routePrefix": ""
+    },
+    "durableTask": {
+      "hubName": "tokencredentialsample",
+      "UseGracefulShutdown": true,
+      "storageProvider": {
+        "type": "Netherite",
+        "StorageConnectionName": "MyConnection",
+        "EventHubsConnectionName": "MyConnection"
+      }
+    }
+  }
+}

samples/TokenCredentialDTFx/HelloCities.cs

@@ -0,0 +1,29 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using DurableTask.Core;
+
+public class HelloSequence : TaskOrchestration<List<string>, string>
+{
+    public override async Task<List<string>> RunTask(OrchestrationContext context, string input)
+    {
+        var result = new List<string>
+        {
+            await context.ScheduleTask<string>(typeof(SayHello), "Tokyo"),
+            await context.ScheduleTask<string>(typeof(SayHello), "Seattle"),
+            await context.ScheduleTask<string>(typeof(SayHello), "London"),
+        };
+
+        return result;
+    }
+}
+
+public class SayHello : TaskActivity<string, string>
+{
+    protected override string Execute(TaskContext context, string input)
+    {
+        return $"Hello, {input}!";
+    }
+}
+

samples/TokenCredentialDTFx/Program.cs

@@ -0,0 +1,76 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using Azure.Identity;
+using DurableTask.Core;
+using DurableTask.Netherite;
+using Microsoft.Extensions.Logging;
+using Newtonsoft.Json;
+
+// ----------- construct the Netherite orchestration service
+
+Console.WriteLine("Starting Netherite...");
+
+var netheriteSettings = new NetheriteOrchestrationServiceSettings()
+{
+    HubName = "myhub",
+    PartitionCount = 4,
+};
+
+netheriteSettings.Validate(ConnectionResolver.FromTokenCredential(
+    new DefaultAzureCredential(),
+    Environment.GetEnvironmentVariable("AccountName") ?? throw new Exception("missing env var: AccountName"),
+    Environment.GetEnvironmentVariable("NamespaceName") ?? throw new Exception("missing env var: NamespaceName")
+));
+
+var loggerFactory = LoggerFactory.Create(builder =>
+{
+    builder.AddSimpleConsole(options => options.SingleLine = true);
+});
+
+NetheriteOrchestrationService netherite = new NetheriteOrchestrationService(netheriteSettings, loggerFactory);
+
+
+// ----------  create the task hub in storage, if it does not already exist
+
+await ((IOrchestrationService) netherite).CreateIfNotExistsAsync();
+
+
+// ---------- configure and start the DTFx worker
+
+var worker = new TaskHubWorker(netherite, loggerFactory);
+
+worker.AddTaskOrchestrations(typeof(HelloSequence));
+worker.AddTaskActivities(typeof(SayHello));
+
+await worker.StartAsync();
+
+
+// ---------- configure the taskhub client
+
+var client = new TaskHubClient(netherite);
+
+
+// --------- start the orchestration, then wait for it to complete
+
+Console.WriteLine("Starting the orchestration...");
+
+OrchestrationInstance instance = await client.CreateOrchestrationInstanceAsync(typeof(HelloSequence), null);
+
+Console.WriteLine("Waiting for completion...");
+
+OrchestrationState taskResult = await client.WaitForOrchestrationAsync(instance, TimeSpan.FromSeconds(30), CancellationToken.None);
+
+Console.WriteLine($"Result:\n{JsonConvert.SerializeObject(taskResult, Formatting.Indented)}\n");
+
+
+// --------- shut down the service
+
+Console.WriteLine("Press any key to shut down...");
+Console.ReadKey();
+
+Console.WriteLine($"Shutting down...");
+
+await worker.StopAsync();
+
+Console.WriteLine("Done.");

samples/TokenCredentialDTFx/README.md

@@ -0,0 +1,19 @@
+# Token Credential Sample
+
+This sample demonstrates how to configure a connection resolver when using Netherite as the orchestration provider for a Durable Task project.
+
+The connection resolver allows you to supply a Azure Token Credential instead of a connection string, which means you can use identity-based authentication.
+
+For this sample, we use the default Azure Identity credential as provided by the Azure.Identity package.
+
+## Configuration Prerequisites
+
+Before running this sample, you must
+
+1. Create a new Azure Storage account, or reuse an existing one
+2. Create a new Azure Event Hubs namespace, or reuse an existing one (that is not currently in use)
+3. Make sure you have [Storage Blob Data Contributor](https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#storage-blob-data-contributor) and [Storage Table Data Contributor](https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#storage-table-data-contributor) permissions for the storage account.
+4. Make sure you have [Azure Event Hubs Data Owner](https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#azure-event-hubs-data-owner) permission for the event hubs namespace.
+5. Set `AccountName` to contain the name of the storage account, using an environment variable or a function app configuration setting,
+6. Set `NamespaceName` to contain the name of the Event Hubs namespace, using an environment variable or a function app configuration setting.
+

samples/TokenCredentialDTFx/TokenCredentialDTFx.csproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Azure.Identity" Version="1.7.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="6.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\DurableTask.Netherite\DurableTask.Netherite.csproj" />
+  </ItemGroup>
+
+</Project>

src/DurableTask.Netherite.AzureFunctions/BlobLogger.cs

@@ -8,6 +8,7 @@ namespace DurableTask.Netherite.AzureFunctions
     using System.Collections.Concurrent;
     using System.IO;
     using System.Threading;
+    using System.Threading.Tasks;
     using Microsoft.Azure.Storage;
     using Microsoft.Azure.Storage.Blob;
     using Microsoft.Extensions.Azure;
@@ -19,7 +20,7 @@ namespace DurableTask.Netherite.AzureFunctions
     class BlobLogger
     {
         readonly DateTime starttime;
-        readonly CloudAppendBlob blob;
+        readonly Task<CloudAppendBlob> blob;
         readonly object flushLock = new object();
         readonly object lineLock = new object();
         readonly ConcurrentQueue<MemoryStream> writebackQueue;
@@ -30,16 +31,21 @@ namespace DurableTask.Netherite.AzureFunctions
         readonly Timer timer;
 #pragma warning restore IDE0052 
 
-        public BlobLogger(string storageConnectionString, string hubName, string workerId)
+        public BlobLogger(ConnectionInfo storageConnection, string hubName, string workerId)
         {
             this.starttime = DateTime.UtcNow;
 
-            CloudStorageAccount storageAccount = CloudStorageAccount.Parse(storageConnectionString);
-            CloudBlobClient client = storageAccount.CreateCloudBlobClient();
-            CloudBlobContainer container = client.GetContainerReference("logs");
-            container.CreateIfNotExists();
-            this.blob = container.GetAppendBlobReference($"{hubName}.{workerId}.{this.starttime:o}.log");
-            this.blob.CreateOrReplace();
+            this.blob = GetBlobAsync();
+            async Task<CloudAppendBlob> GetBlobAsync()
+            {
+                CloudStorageAccount storageAccount = await storageConnection.GetAzureStorageV11AccountAsync();
+                CloudBlobClient client = storageAccount.CreateCloudBlobClient();
+                CloudBlobContainer container = client.GetContainerReference("logs");
+                container.CreateIfNotExists();
+                var blob = container.GetAppendBlobReference($"{hubName}.{workerId}.{this.starttime:o}.log");
+                await blob.CreateOrReplaceAsync();
+                return blob;
+            }
 
             this.memoryStream = new MemoryStream();
             this.writer = new StreamWriter(this.memoryStream);
@@ -89,7 +95,7 @@ namespace DurableTask.Netherite.AzureFunctions
                     {
                         // save to storage
                         toSave.Seek(0, SeekOrigin.Begin);
-                        this.blob.AppendFromStream(toSave);
+                        this.blob.GetAwaiter().GetResult().AppendFromStream(toSave);
                         toSave.Dispose();
                     }
                 }

src/DurableTask.Netherite.AzureFunctions/CredentialBasedConnectionNameResolver.cs

@@ -0,0 +1,80 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite.AzureFunctions
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+    using Azure.Identity;
+    using Microsoft.Extensions.Logging.Abstractions;
+
+#if !NETCOREAPP2_2
+
+    /// <summary>
+    /// Resolves connections using a token credential and a mapping from connection names to resource names.
+    /// </summary>
+    public abstract class CredentialBasedConnectionNameResolver : DurableTask.Netherite.ConnectionResolver
+    {
+        readonly Azure.Core.TokenCredential tokenCredential;
+
+        /// <summary>
+        /// Create a connection resolver that uses an Azure token credential.
+        /// </summary>
+        /// <param name="tokenCredential">The token credential to use.</param>
+        public CredentialBasedConnectionNameResolver(Azure.Core.TokenCredential tokenCredential)
+        {      
+            this.tokenCredential = tokenCredential;
+        }
+
+        public abstract string GetStorageAccountName(string connectionName);
+
+        public abstract string GetEventHubsNamespaceName(string connectionName);
+
+        /// <inheritdoc/>
+        public override ConnectionInfo ResolveConnectionInfo(string taskHub, string connectionName, ResourceType recourceType)
+        {
+            switch (recourceType)
+            {
+                case ResourceType.BlobStorage:
+                case ResourceType.TableStorage:
+                    string storageAccountName = this.GetStorageAccountName(connectionName);
+                    if (string.IsNullOrEmpty(storageAccountName))
+                    {
+                        throw new ArgumentException("GetStorageAccountName returned invalid result");
+                    }
+                    return ConnectionInfo.FromTokenCredential(this.tokenCredential, storageAccountName, recourceType);
+
+                case ResourceType.PageBlobStorage:
+                    return null; // same as blob storage
+
+                case ResourceType.EventHubsNamespace:
+                    string eventHubsNamespaceName = this.GetEventHubsNamespaceName(connectionName);
+                    if (string.IsNullOrEmpty(eventHubsNamespaceName))
+                    {
+                        throw new ArgumentException("GetEventHubsNamespaceName returned invalid result");
+                    }
+                    return ConnectionInfo.FromTokenCredential(this.tokenCredential, eventHubsNamespaceName, recourceType);
+
+                default:
+                    throw new NotSupportedException("unknown resource type");
+            }   
+        }
+
+        /// <inheritdoc/>
+        public override void ResolveLayerConfiguration(string connectionName, out StorageChoices storageChoice, out TransportChoices transportChoice)
+        {
+            if (TransportConnectionString.IsPseudoConnectionString(connectionName))
+            {
+                TransportConnectionString.Parse(connectionName, out storageChoice, out transportChoice);
+            }
+            else
+            {
+                storageChoice = StorageChoices.Faster;
+                transportChoice = TransportChoices.EventHubs;
+            }
+        }
+    }
+
+#endif
+}

src/DurableTask.Netherite.AzureFunctions/NameResolverBasedConnectionResolver.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite.AzureFunctions
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+    using Azure.Identity;
+    using Microsoft.Azure.WebJobs;
+    using Microsoft.Extensions.Logging.Abstractions;
+
+#if !NETCOREAPP2_2
+
+    /// <summary>
+    /// Resolves connections using a token credential and a mapping from connection names to resource names.
+    /// </summary>
+    class NameResolverBasedConnectionNameResolver : DurableTask.Netherite.ConnectionNameToConnectionStringResolver
+    {
+        public NameResolverBasedConnectionNameResolver(INameResolver nameResolver)
+            : base((string name) => nameResolver.Resolve(name))
+        {      
+        }
+    }
+
+#endif
+}

src/DurableTask.Netherite.AzureFunctions/NetheriteProviderFactory.cs

@@ -13,6 +13,7 @@ namespace DurableTask.Netherite.AzureFunctions
     using Microsoft.Azure.WebJobs;
     using Microsoft.Azure.WebJobs.Extensions.DurableTask;
     using Microsoft.Azure.WebJobs.Host.Executors;
+    using Microsoft.Extensions.DependencyInjection;
     using Microsoft.Extensions.Logging;
     using Microsoft.Extensions.Options;
     using Newtonsoft.Json;
@@ -28,6 +29,8 @@ namespace DurableTask.Netherite.AzureFunctions
         readonly DurableTaskOptions options;
         readonly INameResolver nameResolver;
         readonly IHostIdProvider hostIdProvider;
+        readonly IServiceProvider serviceProvider;
+        readonly DurableTask.Netherite.ConnectionResolver connectionResolver;
 
         readonly bool inConsumption;
         
@@ -44,7 +47,10 @@ namespace DurableTask.Netherite.AzureFunctions
         public const string ProviderName = "Netherite";
         public string Name => ProviderName;
 
-        // Called by the Azure Functions runtime dependency injection infrastructure
+        /// <summary>
+        /// This constructor should not be called directly. It is here only to avoid breaking changes.
+        /// </summary>
+        [Obsolete]
         public NetheriteProviderFactory(
             IOptions<DurableTaskOptions> extensionOptions,
             ILoggerFactory loggerFactory,
@@ -55,13 +61,34 @@ namespace DurableTask.Netherite.AzureFunctions
             INameResolver nameResolver,
 #pragma warning disable CS0612 // Type or member is obsolete
             IPlatformInformation platformInfo)
+#pragma warning restore CS0612 // Type or member is obsolete
+            : this(extensionOptions, loggerFactory, hostIdProvider, nameResolver, serviceProvider:null, ConnectionResolver.FromConnectionNameToConnectionStringResolver((s) => nameResolver.Resolve(s)), platformInfo)
+        {
+        }
+
+        /// <summary>
+        /// This constructor should not be called directly. The DI logic calls this when it constructs all the
+        /// durability provider factories for use by <see cref="Microsoft.Azure.WebJobs.Extensions.DurableTask.DurableTaskExtension"/>.
+        /// </summary>
+        [ActivatorUtilitiesConstructor]
+        public NetheriteProviderFactory(
+            IOptions<DurableTaskOptions> extensionOptions,
+            ILoggerFactory loggerFactory,
+            IHostIdProvider hostIdProvider,
+            INameResolver nameResolver,
+            IServiceProvider serviceProvider,
+            DurableTask.Netherite.ConnectionResolver connectionResolver,
+#pragma warning disable CS0612 // Type or member is obsolete
+            IPlatformInformation platformInfo)
 #pragma warning restore CS0612 // Type or member is obsolete
         {
             this.options = extensionOptions?.Value ?? throw new ArgumentNullException(nameof(extensionOptions));
             this.loggerFactory = loggerFactory ?? throw new ArgumentNullException(nameof(loggerFactory));
             this.nameResolver = nameResolver ?? throw new ArgumentNullException(nameof(nameResolver));
 
+            this.serviceProvider = serviceProvider;
             this.hostIdProvider = hostIdProvider;
+            this.connectionResolver = connectionResolver;
             this.inConsumption = platformInfo.IsInConsumptionPlan();
 
             bool ReadBooleanSetting(string name) => this.options.StorageProvider.TryGetValue(name, out object objValue)
@@ -114,15 +141,29 @@ namespace DurableTask.Netherite.AzureFunctions
                 netheriteSettings.HubName = taskHubNameOverride;
             }
 
+            // connections for Netherite are resolved either via an injected custom resolver, or otherwise by resolving connection names to connection strings
+            
             if (!string.IsNullOrEmpty(connectionName))
             {
-                int pos = connectionName.IndexOf(',');
-                if (pos == -1 || pos == 0 || pos == connectionName.Length - 1 || pos != connectionName.LastIndexOf(','))
+                if (this.connectionResolver is NameResolverBasedConnectionNameResolver)
                 {
-                    throw new ArgumentException("For Netherite, connection name must contain both StorageConnectionName and EventHubsConnectionName, separated by a comma", "connectionName");
+                    // the application does not define a custom connection resolver.
+                    // We split the connection name into two connection names, one for storage and one for event hubs
+                    int pos = connectionName.IndexOf(',');
+                    if (pos == -1 || pos == 0 || pos == connectionName.Length - 1 || pos != connectionName.LastIndexOf(','))
+                    {
+                        throw new ArgumentException("For Netherite, connection name must contain both StorageConnectionName and EventHubsConnectionName, separated by a comma", "connectionName");
+                    }
+                    netheriteSettings.StorageConnectionName = connectionName.Substring(0, pos).Trim();
+                    netheriteSettings.EventHubsConnectionName = connectionName.Substring(pos + 1).Trim();
+                }
+                else
+                {
+                    // the application resolves connection names using a custom resolver,
+                    // which can create connections for different resources as needed
+                    netheriteSettings.StorageConnectionName = connectionName;
+                    netheriteSettings.EventHubsConnectionName = connectionName;
                 }
-                netheriteSettings.StorageConnectionName = connectionName.Substring(0, pos).Trim();
-                netheriteSettings.EventHubsConnectionName = connectionName.Substring(pos + 1).Trim();
             }
 
             string runtimeLanguage = this.nameResolver.Resolve("FUNCTIONS_WORKER_RUNTIME");
@@ -131,7 +172,8 @@ namespace DurableTask.Netherite.AzureFunctions
                 netheriteSettings.CacheOrchestrationCursors = false; // cannot resume orchestrations in the middle
             }
 
-            netheriteSettings.Validate((name) => this.nameResolver.Resolve(name));
+            // validate the settings and resolve the connections
+            netheriteSettings.Validate(this.connectionResolver);
 
             int randomProbability = 0;
             bool attachFaultInjector =
@@ -186,10 +228,10 @@ namespace DurableTask.Netherite.AzureFunctions
             {
                 if (this.TraceToBlob && BlobLogger == null)
                 {
-                    BlobLogger = new BlobLogger(settings.ResolvedStorageConnectionString, settings.HubName, settings.WorkerId);
+                    BlobLogger = new BlobLogger(settings.BlobStorageConnection, settings.HubName, settings.WorkerId);
                 }
 
-                var service = new NetheriteOrchestrationService(settings, this.loggerFactory);
+                var service = new NetheriteOrchestrationService(settings, this.loggerFactory, this.serviceProvider);
 
                 service.OnStopping += () => CachedProviders.TryRemove(key, out var _);
 

src/DurableTask.Netherite.AzureFunctions/NetheriteProviderStartup.cs

@@ -9,6 +9,7 @@ namespace DurableTask.Netherite.AzureFunctions
     using Microsoft.Azure.WebJobs.Extensions.DurableTask;
     using Microsoft.Azure.WebJobs.Hosting;
     using Microsoft.Extensions.DependencyInjection;
+    using Microsoft.Extensions.DependencyInjection.Extensions;
 
     class NetheriteProviderStartup : IWebJobsStartup
     {
@@ -16,6 +17,7 @@ namespace DurableTask.Netherite.AzureFunctions
         {
 #if !NETCOREAPP2_2
             builder.Services.AddSingleton<IDurabilityProviderFactory, NetheriteProviderFactory>();
+            builder.Services.TryAddSingleton<ConnectionResolver, NameResolverBasedConnectionNameResolver>();
 #else
             builder.Services.AddSingleton<IDurabilityProviderFactory, NetheriteProviderPseudoFactory>();
 #endif

src/DurableTask.Netherite/AssemblyInfo.cs

@@ -1,6 +1,12 @@
 using System.Runtime.CompilerServices;
 
 [assembly: InternalsVisibleTo("DurableTask.Netherite.Tests, PublicKey="
+    + "0024000004800000940000000602000000240000525341310004000001000100e93024fd5f6737"
+    + "b5f408b39a97e746f673e7c62d690716c6022ee8871b2bc5efcbd8015dd02253302196ded0d9fc"
+    + "0c6bc0e84740f74ca828fed9aebf15272867019cf991484c06b00c7d7aacb34b40ed0ae633f043"
+    + "2df41db65caa4b03f9a0e6974c15aeaa7db2acd902914c0628f0b77d9b7839f530ba04584aed92"
+    + "87159ebd")]
+[assembly: InternalsVisibleTo("DurableTask.Netherite.AzureFunctions, PublicKey="
     + "0024000004800000940000000602000000240000525341310004000001000100e93024fd5f6737"
     + "b5f408b39a97e746f673e7c62d690716c6022ee8871b2bc5efcbd8015dd02253302196ded0d9fc"
     + "0c6bc0e84740f74ca828fed9aebf15272867019cf991484c06b00c7d7aacb34b40ed0ae633f043"

src/DurableTask.Netherite/Connections/CompatibilityConnectionResolver.cs

@@ -0,0 +1,92 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Data;
+    using System.Text;
+    using Microsoft.Azure.Storage;
+    using Microsoft.Extensions.Logging.Abstractions;
+
+
+    /// <summary>
+    /// Resolves connection names by using a mapping from connection names to connection strings,
+    /// or an already resolved connection string if specified inside the settings object.
+    /// Used for compatibility with old configuration scheme.
+    /// </summary>
+    class CompatibilityConnectionResolver : ConnectionNameToConnectionStringResolver
+    {
+        readonly NetheriteOrchestrationServiceSettings settings;
+
+        /// <summary>
+        /// Creates a connection string resolver for a given lookup function.
+        /// </summary>
+        /// <param name="connectionStringLookup">A function that maps connection names to connection strings.</param>
+        public CompatibilityConnectionResolver(NetheriteOrchestrationServiceSettings settings, Func<string, string> connectionStringLookup)
+            : base(connectionStringLookup)
+        {
+            this.settings = settings;
+        }
+
+#pragma warning disable CS0618 // Type or member is obsolete
+
+        /// <inheritdoc/>
+        public override ConnectionInfo ResolveConnectionInfo(string taskHub, string connectionName, ResourceType recourceType)
+        {
+            switch (recourceType)
+            {
+                case ResourceType.EventHubsNamespace:
+                    if (!string.IsNullOrEmpty(this.settings.ResolvedTransportConnectionString))
+                    {
+                        return ConnectionInfo.FromEventHubsConnectionString(this.settings.ResolvedTransportConnectionString);
+                    }
+                    else
+                    {
+                        break;
+                    }
+
+                case ResourceType.BlobStorage:
+                case ResourceType.TableStorage:
+                    if (!string.IsNullOrEmpty(this.settings.ResolvedStorageConnectionString))
+                    {
+                        return ConnectionInfo.FromStorageConnectionString(this.settings.ResolvedStorageConnectionString, recourceType);
+                    }
+                    else
+                    {
+                        break;
+                    }
+
+                case ResourceType.PageBlobStorage:
+                    var resolved = this.settings.ResolvedPageBlobStorageConnectionString ?? this.settings.ResolvedStorageConnectionString;
+                    if (!string.IsNullOrEmpty(resolved))
+                    {
+                        return ConnectionInfo.FromStorageConnectionString(resolved, recourceType);
+                    }
+                    else
+                    {
+                        break;
+                    }
+            }
+
+            return base.ResolveConnectionInfo(taskHub, connectionName, recourceType);
+        }
+
+        /// <inheritdoc/>
+        public override void ResolveLayerConfiguration(string connectionName, out StorageChoices storageChoice, out TransportChoices transportChoice)
+        {
+            if (TransportConnectionString.IsPseudoConnectionString(this.settings.ResolvedTransportConnectionString))
+            {
+                TransportConnectionString.Parse(this.settings.ResolvedTransportConnectionString, out storageChoice, out transportChoice);
+            }
+            else
+            {
+                base.ResolveLayerConfiguration(connectionName, out storageChoice, out transportChoice);
+            }
+        }
+
+#pragma warning restore CS0618 // Type or member is obsolete
+    }
+}
+

src/DurableTask.Netherite/Connections/ConnectionInfo.cs

@@ -0,0 +1,148 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Threading.Tasks;
+    using Microsoft.Azure.Storage;
+
+    /// <summary>
+    /// Internal abstraction used for capturing connection information and credentials.
+    /// Represents all different kinds of storage (blobs, tables, event hubs namespaces).
+    /// </summary>
+    public partial class ConnectionInfo
+    {
+        /// <summary>
+        ///  The name of the resource.
+        /// </summary>
+        public string ResourceName { get; set; }
+
+        /// <summary>
+        /// A connection string for accessing this resource.
+        /// (may be null if using a <see cref="TokenCredential"/>).
+        /// </summary>
+        public string ConnectionString { get; set; }
+
+        /// <summary>
+        /// A token credential for accessing this resource.
+        /// (may be null if using a <see cref="ConnectionString"/>).
+        /// </summary>
+        public Azure.Core.TokenCredential TokenCredential { get; set; }
+
+        /// <summary>
+        /// The fully qualified name for the resource. 
+        /// </summary>
+        public string HostName { get; set; }
+
+        /// <summary>
+        /// Scopes for the token.
+        /// </summary>
+        public string[] Scopes;
+
+        protected static readonly string[] s_storage_scopes = { "https://storage.azure.com/.default" };
+        protected static readonly string[] s_eventhubs_scopes = { "https://eventhubs.azure.net/.default" };
+
+        /// <summary>
+        /// Creates a connection info from an event hubs connection string
+        /// </summary>
+        /// <param name="connectionString">The connection string.</param>
+        /// <returns>The connection info.</returns>
+        public static ConnectionInfo FromEventHubsConnectionString(string connectionString)
+        {
+            var properties = Azure.Messaging.EventHubs.EventHubsConnectionStringProperties.Parse(connectionString);
+            string hostName = properties.FullyQualifiedNamespace;
+            string nameSpaceName = hostName.Split('.')[0];
+
+            return new ConnectionInfo()
+            {
+                ResourceName = nameSpaceName,
+                ConnectionString = connectionString,
+                TokenCredential = null,
+                HostName = hostName,
+                Scopes = s_eventhubs_scopes,
+            };
+        }
+
+        /// <summary>
+        /// Creates a connection info from a storage connection string
+        /// </summary>
+        /// <param name="connectionString">The connection string.</param>
+        /// <param name="resourceType">The resource type being accessed.</param>
+        /// <returns>The connection info.</returns>
+        public static ConnectionInfo FromStorageConnectionString(string connectionString, ConnectionResolver.ResourceType resourceType)
+        {
+            var cloudStorageAccount = CloudStorageAccount.Parse(connectionString);
+            return new ConnectionInfo()
+            {
+                ResourceName = cloudStorageAccount.Credentials.AccountName,
+                ConnectionString = connectionString,
+                TokenCredential = null,
+                HostName = GetEndpoint().Host,
+                Scopes = s_storage_scopes,
+            };
+
+            Uri GetEndpoint() => resourceType == ConnectionResolver.ResourceType.TableStorage 
+                ? cloudStorageAccount.TableEndpoint : cloudStorageAccount.BlobEndpoint;
+        }
+
+        /// <summary>
+        /// Creates a connection info from a token credential.
+        /// </summary>
+        /// <param name="tokenCredential">The token credential.</param>
+        /// <param name="name">The name of the resource (account name or namespace name).</param>
+        /// <param name="resourceType">The type of the resource.</param>
+        /// <returns></returns>
+        /// <returns>The connection info.</returns>
+        public static ConnectionInfo FromTokenCredential(Azure.Core.TokenCredential tokenCredential, string name, ConnectionResolver.ResourceType resourceType)
+        {
+            switch (resourceType)
+            {
+                case ConnectionResolver.ResourceType.EventHubsNamespace:
+                    {
+                        return new ConnectionInfo()
+                        {
+                            ResourceName = name,
+                            ConnectionString = null,
+                            TokenCredential = tokenCredential,
+                            HostName = $"{name}.servicebus.windows.net",
+                            Scopes = s_eventhubs_scopes,
+                        };
+                    }
+
+                case ConnectionResolver.ResourceType.BlobStorage:
+                case ConnectionResolver.ResourceType.PageBlobStorage:
+                    return new ConnectionInfo()
+                    {
+                        ResourceName = name,
+                        ConnectionString = null,
+                        TokenCredential = tokenCredential,
+                        HostName = $"{name}.blob.core.windows.net",
+                        Scopes = s_storage_scopes,
+                    };
+
+
+                case ConnectionResolver.ResourceType.TableStorage:
+                    {
+                        return new ConnectionInfo()
+                        {
+                            ResourceName = name,
+                            ConnectionString = null,
+                            TokenCredential = tokenCredential,
+                            HostName = $"{name}.table.core.windows.net",
+                            Scopes = s_storage_scopes,
+                        };
+                    }
+
+                default:
+                    return null;
+            }
+        }
+
+        /// <summary>
+        /// When converting to a classic storage account, a renewal timer is associated with each CloudStorageAccount instance. We therefore use
+        /// a single instance to be shared by all.
+        /// </summary>
+        internal Task<Microsoft.Azure.Storage.CloudStorageAccount> CachedStorageAccountTask;
+    }
+}

src/DurableTask.Netherite/Connections/ConnectionInfoExtensions.cs

@@ -0,0 +1,219 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+    using System.Threading.Tasks;
+    using System.Threading;
+    using System.Net.Cache;
+    using System.Net.Http;
+    using System.Globalization;
+    using System.Security.Cryptography;
+    using System.Web;
+    using DurableTask.Netherite.EventHubsTransport;
+    using Microsoft.Azure.EventHubs;
+    using Azure.Core;
+    using System.Runtime.CompilerServices;
+    using Microsoft.Azure.EventHubs.Processor;
+    using Newtonsoft.Json.Serialization;
+    using DurableTask.Netherite.Faster;
+
+    /// <summary>
+    /// Utilities for constructing various SDK objects from a connection information.
+    /// </summary>
+    static class ConnectionInfoExtensions
+    {
+        /// <summary>
+        /// Returns a classic (v11 SDK) storage account object.
+        /// </summary>
+        /// <param name="connectionInfo">The connection info.</param>
+        /// <returns>A task for the storage account object.</returns>
+        /// <exception cref="FormatException">Thrown if the host name of the connection info is not of the expected format {ResourceName}.{HostNameSuffix}.</exception>
+        public static Task<Microsoft.Azure.Storage.CloudStorageAccount> GetAzureStorageV11AccountAsync(this ConnectionInfo connectionInfo)
+        {
+            // storage accounts run a token renewal timer, so we want to share a single instance
+            if (connectionInfo.CachedStorageAccountTask == null)
+            {
+                connectionInfo.CachedStorageAccountTask = GetAsync();
+            }
+            return connectionInfo.CachedStorageAccountTask;
+
+            async Task<Microsoft.Azure.Storage.CloudStorageAccount> GetAsync()
+            {
+                if (connectionInfo.ConnectionString != null)
+                {
+                    return Microsoft.Azure.Storage.CloudStorageAccount.Parse(connectionInfo.ConnectionString);
+                }
+                else
+                {
+                    var credentials = new Microsoft.Azure.Storage.Auth.StorageCredentials(await connectionInfo.ToLegacyCredentialAsync(CancellationToken.None));
+
+                    // hostnames are generally structured like
+                    //    accountname.blob.core.windows.net
+                    //    accountname.table.core.windows.net
+                    //    databasename.table.cosmos.azure.com
+
+                    int firstDot = connectionInfo.HostName.IndexOf('.');
+                    int secondDot = connectionInfo.HostName.IndexOf('.', firstDot + 1);
+                    string hostNameSuffix = connectionInfo.HostName.Substring(secondDot + 1);
+
+                    return new Microsoft.Azure.Storage.CloudStorageAccount(
+                            storageCredentials: credentials,
+                            accountName: connectionInfo.ResourceName,
+                            endpointSuffix: hostNameSuffix,
+                            useHttps: true);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Creates an Azure Storage table client for the v12 SDK.
+        /// </summary>
+        /// <param name="connectionInfo">The connection info.</param>
+        /// <param name="tableName">The table name.</param>
+        /// <param name="cancellationToken">A cancellation token.</param>
+        /// <returns></returns>
+        public static Azure.Data.Tables.TableClient GetAzureStorageV12TableClientAsync(this ConnectionInfo connectionInfo, string tableName, CancellationToken cancellationToken = default)
+        {
+            if (connectionInfo.ConnectionString != null)
+            {
+                return new Azure.Data.Tables.TableClient(connectionInfo.ConnectionString, tableName);
+            }
+            else
+            {
+                return new Azure.Data.Tables.TableClient(new Uri($"https://{connectionInfo.HostName}/"), tableName, connectionInfo.TokenCredential);
+            }
+        }
+
+        /// <summary>
+        /// Creates an Event Hub client for the given connection info.
+        /// </summary>
+        /// <param name="connectionInfo">The connection info.</param>
+        /// <param name="eventHub">The event hub name.</param>
+        /// <returns></returns>
+        public static EventHubClient CreateEventHubClient(this ConnectionInfo connectionInfo, string eventHub)
+        {
+            if (connectionInfo.ConnectionString != null)
+            {
+                var connectionStringBuilder = new EventHubsConnectionStringBuilder(connectionInfo.ConnectionString)
+                {
+                    EntityPath = eventHub
+                };
+                return EventHubClient.CreateFromConnectionString(connectionStringBuilder.ToString());
+            }
+            else
+            {
+                Uri uri = new Uri($"sb://{connectionInfo.HostName}");
+                var tokenProvider = new EventHubsTokenProvider(connectionInfo);
+                return EventHubClient.CreateWithTokenProvider(uri, eventHub, tokenProvider);
+            }
+        }
+
+        /// <summary>
+        /// Creates an event processor host for the given connection info.
+        /// </summary>
+        /// <param name="connectionInfo">The connection info.</param>
+        /// <param name="hostName">The host name.</param>
+        /// <param name="eventHubPath">The event hub name.</param>
+        /// <param name="consumerGroupName">The consumer group name.</param>
+        /// <param name="checkpointStorage">A connection info for the checkpoint storage.</param>
+        /// <param name="leaseContainerName">The name of the lease container.</param>
+        /// <param name="storageBlobPrefix">A prefix for storing the blobs.</param>
+        /// <returns>An event processor host.</returns>
+        public static async Task<EventProcessorHost> GetEventProcessorHostAsync(
+            this ConnectionInfo connectionInfo, 
+            string hostName,
+            string eventHubPath,
+            string consumerGroupName,
+            ConnectionInfo checkpointStorage,
+            string leaseContainerName,
+            string storageBlobPrefix)
+        {
+            if (connectionInfo.ConnectionString != null)
+            {
+                return new EventProcessorHost(
+                       hostName,
+                       eventHubPath,
+                       consumerGroupName,
+                       connectionInfo.ConnectionString,
+                       checkpointStorage.ConnectionString,
+                       leaseContainerName,
+                       storageBlobPrefix);
+            }
+            else
+            {
+                var storageAccount = await checkpointStorage.GetAzureStorageV11AccountAsync();
+                return new EventProcessorHost(
+                      new Uri($"sb://{connectionInfo.HostName}"),
+                      eventHubPath,
+                      consumerGroupName,
+                      (ITokenProvider) (new EventHubsTokenProvider(connectionInfo)),
+                      storageAccount,
+                      leaseContainerName,
+                      storageBlobPrefix);
+            }
+        }
+
+        class EventHubsTokenProvider : Microsoft.Azure.EventHubs.ITokenProvider
+        {
+            readonly ConnectionInfo info;
+
+            public EventHubsTokenProvider(ConnectionInfo info)
+            {
+                this.info = info;
+            }
+
+            static TimeSpan NextRefresh(AccessToken token)
+            {
+                DateTimeOffset now = DateTimeOffset.UtcNow;
+                return token.ExpiresOn - now - TimeSpan.FromMinutes(1); // refresh it a bit early.
+            }
+
+            async Task<SecurityToken> ITokenProvider.GetTokenAsync(string appliesTo, TimeSpan timeout)
+            {
+                TokenRequestContext request = new(this.info.Scopes);
+                AccessToken accessToken = await this.info.TokenCredential.GetTokenAsync(request, CancellationToken.None);
+                return new JsonSecurityToken(accessToken.Token, appliesTo);
+            }
+        }
+
+        /// <summary>
+        /// Adds the necessary authorization headers to a REST http request.
+        /// </summary>
+        /// <param name="connectionInfo">The connection info.</param>
+        /// <param name="request">The request object.</param>
+        /// <param name="cancellationToken">A cancellation token.</param>
+        /// <returns></returns>
+        public static async Task AuthorizeHttpRequestMessage(this ConnectionInfo connectionInfo, HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            if (connectionInfo.ConnectionString != null)
+            {
+                // parse the eventhubs connection string to extract various parameters
+                var properties = Azure.Messaging.EventHubs.EventHubsConnectionStringProperties.Parse(connectionInfo.ConnectionString);
+                string resourceUri = properties.Endpoint.AbsoluteUri;
+                string keyName = properties.SharedAccessKeyName; 
+                string key = properties.SharedAccessKey;
+
+                // create a token (from https://docs.microsoft.com/en-us/rest/api/eventhub/generate-sas-token#c)
+                TimeSpan sinceEpoch = DateTime.UtcNow - new DateTime(1970, 1, 1);
+                var week = 60 * 60 * 24 * 7;
+                var expiry = Convert.ToString((int)sinceEpoch.TotalSeconds + week);
+                string stringToSign = HttpUtility.UrlEncode(resourceUri) + "\n" + expiry;
+                HMACSHA256 hmac = new HMACSHA256(Encoding.UTF8.GetBytes(key));
+                var signature = Convert.ToBase64String(hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign)));
+                var sasToken = String.Format(CultureInfo.InvariantCulture, "SharedAccessSignature sr={0}&sig={1}&se={2}&skn={3}", HttpUtility.UrlEncode(resourceUri), HttpUtility.UrlEncode(signature), expiry, keyName);
+               
+                //add it to the request
+                request.Headers.Add("Authorization", sasToken);
+            }
+            else
+            {
+                var bearerToken = (await connectionInfo.ToLegacyCredentialAsync(cancellationToken)).Token;
+                request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", bearerToken);
+            }
+        }
+    }
+}

src/DurableTask.Netherite/Connections/ConnectionNameToConnectionStringResolver.cs

@@ -0,0 +1,76 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Data;
+    using System.Text;
+    using Microsoft.Azure.Storage;
+    using Microsoft.Extensions.Logging.Abstractions;
+
+    /// <summary>
+    /// Resolves connection names by using a mapping from connection names to connection strings.
+    /// </summary>
+    class ConnectionNameToConnectionStringResolver : ConnectionResolver
+    {
+        readonly Func<string, string> connectionStringLookup;
+
+        /// <summary>
+        /// Creates a connection string resolver for a given lookup function.
+        /// </summary>
+        /// <param name="connectionStringLookup">A function that maps connection names to connection strings.</param>
+        public ConnectionNameToConnectionStringResolver(Func<string, string> connectionStringLookup)
+        {
+            this.connectionStringLookup = connectionStringLookup;
+        }
+
+        /// <inheritdoc/>
+        public override ConnectionInfo ResolveConnectionInfo(string taskHub, string connectionName, ResourceType recourceType)
+        {
+            var connectionString = this.connectionStringLookup?.Invoke(connectionName);
+
+            if (connectionString == null)
+            {
+                return null;
+            }
+            else if (recourceType == ResourceType.EventHubsNamespace)
+            {
+                return ConnectionInfo.FromEventHubsConnectionString(connectionString);
+            }
+            else if (recourceType == ResourceType.PageBlobStorage)
+            {
+                return null; // this resolver does not support using a separate page blob connection
+            }
+            else
+            {
+                return ConnectionInfo.FromStorageConnectionString(connectionString, recourceType);
+            }
+        }
+
+        /// <inheritdoc/>
+        public override void ResolveLayerConfiguration(string connectionName, out StorageChoices storageChoice, out TransportChoices transportChoice)
+        {
+            if (TransportConnectionString.IsPseudoConnectionString(connectionName))
+            {
+                TransportConnectionString.Parse(connectionName, out storageChoice, out transportChoice);
+            }
+            else
+            {
+                var connectionString = this.connectionStringLookup?.Invoke(connectionName);
+
+                if (TransportConnectionString.IsPseudoConnectionString(connectionString))
+                {
+                    TransportConnectionString.Parse(connectionString, out storageChoice, out transportChoice);
+                }
+                else
+                {
+                    // the default settings are Faster and EventHubs
+                    storageChoice = StorageChoices.Faster;
+                    transportChoice = TransportChoices.EventHubs;
+                }
+            }
+        }
+    }
+}

src/DurableTask.Netherite/Connections/ConnectionResolver.cs

@@ -0,0 +1,91 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+
+    /// <summary>
+    /// An abstract class that represents a method for resolving named connections into ConnectionInfo objects, which can then be used to connect.
+    /// </summary>
+    public abstract class ConnectionResolver
+    {
+        /// <summary>
+        /// The cloud resources for which Netherite may require connection information
+        /// </summary>
+        public enum ResourceType
+        {
+            /// <summary>
+            /// The event hubs namespace. Used for connecting various logical components (partitions, clients, and the load monitor).
+            /// Not required if the layer configuration uses <see cref="TransportChoices.SingleHost"/>.
+            /// </summary>
+            EventHubsNamespace,
+
+            /// <summary>
+            /// The blob storage account, used for task hub storage and event hub consumer checkpoints. 
+            /// Not required if the layer configuration uses <see cref="StorageChoices.Memory"/>.
+            /// </summary>
+            BlobStorage,
+
+            /// <summary>
+            /// The table storage account, used for publishing load information. 
+            /// Not required if <see cref="NetheriteOrchestrationServiceSettings.LoadInformationAzureTableName"/> is set to null, or if
+            /// the layer configuration uses <see cref="StorageChoices.Memory"/>.
+            /// </summary>
+            TableStorage,
+
+            /// <summary>
+            /// The page blob storage account. Optional, can be used for storing page blobs separately from other blobs. 
+            /// </summary>
+            PageBlobStorage,
+        }
+
+        /// <summary>
+        /// Attempts to resolves the given name to obtain connection information.
+        /// </summary>
+        /// <param name="taskHub">The name of the task hub.</param>
+        /// <param name="connectionName">The connection name.</param>
+        /// <param name="recourceType">The type of resource to which a connection is desired to be made.</param>
+        /// <returns>A ConnectionInfo with the required parameters to connect, or null if not found.</returns>
+        public abstract ConnectionInfo ResolveConnectionInfo(string taskHub, string connectionName, ResourceType recourceType);
+
+        /// <summary>
+        /// Determines the layers to use. For example, can configure full emulation by assigning <see cref="StorageChoices.Memory"/> and <see cref="TransportChoices.SingleHost"/>.
+        /// </summary>
+        /// <param name="connectionName">The connection name.</param>
+        /// <param name="storageChoice">The storage layer to use.</param>
+        /// <param name="transportChoice">The transport layer to use.</param>
+        public abstract void ResolveLayerConfiguration(string connectionName, out StorageChoices storageChoice, out TransportChoices transportChoice);
+
+        /// <summary>
+        /// Creates a connection resolver for a given connection string lookup function.
+        /// </summary>
+        /// <param name="connectionStringLookup">A function that maps connection names to connection strings.</param>
+        public static ConnectionResolver FromConnectionNameToConnectionStringResolver(Func<string, string> connectionStringLookup)
+        {
+            return new ConnectionNameToConnectionStringResolver(connectionStringLookup);
+        }
+
+        /// <summary>
+        /// Creates a connection resolver given a token credential, a storage account name, and an event hubs namespace name.
+        /// Applies the default suffixes (*.core.windows.net for storage accounts and *.servicebus.windows.net for event hubs).
+        /// </summary>
+        /// <param name="tokenCredential">The token credential to use.</param>
+        /// <param name="storageAccountName">The name of the storage account.</param>
+        /// <param name="eventHubNamespaceName">The name of the event hub namespace, or null if using the singlehost configuration.</param>   
+        public static ConnectionResolver FromTokenCredential(Azure.Core.TokenCredential tokenCredential, string storageAccountName, string eventHubNamespaceName = null)
+        {
+            return new SimpleCredentialResolver(tokenCredential, storageAccountName, eventHubNamespaceName);
+        }
+
+        /// <summary>
+        /// Creates a connection resolver to use exclusively for in-memory emulation.
+        /// </summary>
+        public static ConnectionResolver ForInMemoryEmulation()
+        {
+            return new SimpleCredentialResolver(null, null, null);
+        }
+    }
+}

src/DurableTask.Netherite/Connections/CredentialShim.cs

@@ -0,0 +1,52 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+    using Azure.Core;
+    using Microsoft.Azure.Storage.Auth;
+    using System.Threading.Tasks;
+    using System.Threading;
+
+    /// <summary>
+    /// A utility class for constructing a <see cref="Microsoft.Azure.Storage.Auth.TokenCredential"/> 
+    /// from a <see cref="Azure.Core.TokenCredential"/>.
+    /// </summary>
+    static class CredentialShim
+    {
+        /// <summary>
+        /// Creates a <see cref="Microsoft.Azure.Storage.Auth.TokenCredential"/> from the connection info. 
+        /// </summary>
+        /// <param name="connectionInfo">The connection info.</param>
+        /// <param name="cancellationToken">A cancellation token.</param>
+        /// <returns></returns>
+        public static async Task<Microsoft.Azure.Storage.Auth.TokenCredential> ToLegacyCredentialAsync(this ConnectionInfo connectionInfo, CancellationToken cancellationToken)
+        {
+            AccessToken token = await GetTokenAsync(connectionInfo.TokenCredential, connectionInfo.Scopes, cancellationToken);
+            return new Microsoft.Azure.Storage.Auth.TokenCredential(token.Token, RenewTokenAsync, connectionInfo, NextRefresh(token));
+        }
+
+        static ValueTask<AccessToken> GetTokenAsync(
+            Azure.Core.TokenCredential credential, string[] scopes, CancellationToken cancellation)
+        {
+            TokenRequestContext request = new(scopes);
+            return credential.GetTokenAsync(request, cancellation);
+        }
+
+        static async Task<NewTokenAndFrequency> RenewTokenAsync(object state, CancellationToken cancellationToken)
+        {
+            ConnectionInfo connectionInfo = (ConnectionInfo)state;
+            AccessToken token = await GetTokenAsync(connectionInfo.TokenCredential, connectionInfo.Scopes, cancellationToken);
+            return new(token.Token, NextRefresh(token));
+        }
+
+        static TimeSpan NextRefresh(AccessToken token)
+        {
+            DateTimeOffset now = DateTimeOffset.UtcNow;
+            return token.ExpiresOn - now - TimeSpan.FromMinutes(1); // refresh it a bit early.
+        }
+    }
+}

src/DurableTask.Netherite/Connections/EventHubsUtil.cs

@@ -24,9 +24,9 @@ namespace DurableTask.Netherite
         /// <param name="eventHubName">The name of the event hub.</param>
         /// <param name="partitionCount">The number of partitions to create, if the event hub does not already exist.</param>
         /// <returns>true if the event hub was created.</returns>
-        public static async Task<bool> EnsureEventHubExistsAsync(string connectionString, string eventHubName, int partitionCount)
+        public static async Task<bool> EnsureEventHubExistsAsync(ConnectionInfo info, string eventHubName, int partitionCount, CancellationToken cancellationToken)
         {
-            var response = await SendHttpRequest(connectionString, eventHubName, partitionCount);
+            var response = await SendHttpRequest(info, eventHubName, partitionCount, cancellationToken);
             if (response.StatusCode != System.Net.HttpStatusCode.Conflict)
             {
                 response.EnsureSuccessStatusCode();
@@ -40,9 +40,9 @@ namespace DurableTask.Netherite
         /// <param name="connectionString">The SAS connection string for the namespace.</param>
         /// <param name="eventHubName">The name of the event hub.</param>
         /// <returns>true if the event hub was deleted.</returns>
-        public static async Task<bool> DeleteEventHubIfExistsAsync(string connectionString, string eventHubName)
+        public static async Task<bool> DeleteEventHubIfExistsAsync(ConnectionInfo info, string eventHubName, CancellationToken cancellationToken)
         {
-            var response = await SendHttpRequest(connectionString, eventHubName, null);
+            var response = await SendHttpRequest(info, eventHubName, null, cancellationToken);
             if (response.StatusCode != System.Net.HttpStatusCode.NotFound)
             {
                 response.EnsureSuccessStatusCode();
@@ -50,35 +50,12 @@ namespace DurableTask.Netherite
             return response.StatusCode == System.Net.HttpStatusCode.OK;
         }
 
-        static Task<HttpResponseMessage> SendHttpRequest(string connectionString, string eventHubName, int? partitionCount)
+        static async Task<HttpResponseMessage> SendHttpRequest(ConnectionInfo info, string eventHubName, int? partitionCount, CancellationToken cancellationToken)
         {
-            // parse the eventhubs connection string to extract various parameters
-            var properties = Azure.Messaging.EventHubs.EventHubsConnectionStringProperties.Parse(connectionString);
-            string resource = properties.FullyQualifiedNamespace;
-            string resourceUri = properties.Endpoint.AbsoluteUri;
-            string name = properties.SharedAccessKeyName;
-            string key = properties.SharedAccessKey;
-
-            // create a token that allows us to create an eventhub
-            string sasToken = createToken(resourceUri, name, key);
-
-            // the following token creation code is taken from https://docs.microsoft.com/en-us/rest/api/eventhub/generate-sas-token#c
-            string createToken(string resourceUri, string name, string key)
-            {
-                TimeSpan sinceEpoch = DateTime.UtcNow - new DateTime(1970, 1, 1);
-                var week = 60 * 60 * 24 * 7;
-                var expiry = Convert.ToString((int)sinceEpoch.TotalSeconds + week);
-                string stringToSign = HttpUtility.UrlEncode(resourceUri) + "\n" + expiry;
-                HMACSHA256 hmac = new HMACSHA256(Encoding.UTF8.GetBytes(key));
-                var signature = Convert.ToBase64String(hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign)));
-                var sasToken = String.Format(CultureInfo.InvariantCulture, "SharedAccessSignature sr={0}&sig={1}&se={2}&skn={3}", HttpUtility.UrlEncode(resourceUri), HttpUtility.UrlEncode(signature), expiry, name);
-                return sasToken;
-            }
-
             // send an http request to create or delete the eventhub
             HttpClient client = new HttpClient();
             var request = new HttpRequestMessage();
-            request.RequestUri = new Uri($"https://{resource}/{eventHubName}?timeout=60&api-version=2014-01");
+            request.RequestUri = new Uri($"https://{info.HostName}/{eventHubName}?timeout=60&api-version=2014-01");
             request.Method = partitionCount.HasValue ? HttpMethod.Put : HttpMethod.Delete;
             if (partitionCount.HasValue)
             {
@@ -94,10 +71,12 @@ namespace DurableTask.Netherite
                                 Encoding.UTF8,
                                 "application/xml");
             }
-            request.Headers.Add("Authorization", sasToken);
-            request.Headers.Add("Host", resource);
+            request.Headers.Add("Host", info.HostName);
 
-            return client.SendAsync(request);
+            // add an authorization header to the request
+            await info.AuthorizeHttpRequestMessage(request, cancellationToken);
+
+            return await client.SendAsync(request);
         }
     }
 }

src/DurableTask.Netherite/Connections/SimpleCredentialResolver.cs

@@ -0,0 +1,74 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+    using Azure.Core;
+    using Microsoft.Extensions.Logging.Abstractions;
+
+    /// <summary>
+    /// Resolves connections using a token credential, a storage account name, and an eventhubs namespace name.
+    /// </summary>
+    class SimpleCredentialResolver : ConnectionResolver
+    {
+        readonly Azure.Core.TokenCredential tokenCredential;
+        readonly string storageAccountName;
+        readonly string eventHubNamespaceName;
+
+        /// <summary>
+        /// Create a connection resolver that uses an Azure token credential.
+        /// </summary>
+        /// <param name="tokenCredential">The token credential to use.</param>
+        /// <param name="storageAccountName">The name of the storage account, or null if using in-memory emulation.</param>
+        /// <param name="eventHubNamespaceName">The name of the event hub namespace, or null if using the singlehost configuration.</param>
+        public SimpleCredentialResolver(Azure.Core.TokenCredential tokenCredential, string storageAccountName = null, string eventHubNamespaceName = null)
+        {
+            this.tokenCredential = tokenCredential;
+            this.storageAccountName = storageAccountName;
+            this.eventHubNamespaceName = eventHubNamespaceName;
+        }
+
+        /// <inheritdoc/>
+        public override ConnectionInfo ResolveConnectionInfo(string taskHub, string connectionName, ResourceType recourceType)
+        {
+            switch (recourceType)
+            {
+                case ResourceType.BlobStorage:
+                case ResourceType.TableStorage:
+                    return ConnectionInfo.FromTokenCredential(this.tokenCredential, this.storageAccountName, recourceType);
+
+                case ResourceType.PageBlobStorage:
+                    return null; // same as blob storage
+
+                case ResourceType.EventHubsNamespace:
+                    return ConnectionInfo.FromTokenCredential(this.tokenCredential, this.eventHubNamespaceName, recourceType);
+
+                default:
+                    throw new NotImplementedException("unknown resource type");
+            }
+        }
+
+        /// <inheritdoc/>
+        public override void ResolveLayerConfiguration(string connectionName, out StorageChoices storageChoice, out TransportChoices transportChoice)
+        {
+            if (string.IsNullOrEmpty(this.storageAccountName))
+            {
+                storageChoice = StorageChoices.Memory;
+                transportChoice = TransportChoices.SingleHost;
+            }
+            else if (string.IsNullOrEmpty(this.eventHubNamespaceName))
+            {
+                storageChoice = StorageChoices.Faster;
+                transportChoice = TransportChoices.SingleHost;
+            }
+            else
+            {
+                storageChoice = StorageChoices.Faster;
+                transportChoice = TransportChoices.EventHubs;
+            }
+        }
+    }
+}

src/DurableTask.Netherite/DurableTask.Netherite.csproj

@@ -50,6 +50,7 @@
   </ItemGroup>
   
   <ItemGroup>
+    <PackageReference Include="Azure.Core" Version="1.25.0" />
     <PackageReference Include="Azure.Data.Tables" Version="12.6.1" />
     <PackageReference Include="Azure.Messaging.EventHubs" Version="5.7.2" />
     <PackageReference Include="Microsoft.Azure.EventHubs.Processor" Version="4.3.2" />

src/DurableTask.Netherite/Events/ClientEvents/ClientEvent.cs

@@ -15,6 +15,7 @@ namespace DurableTask.Netherite
         [DataMember]
         public long RequestId { get; set; }
 
+        [IgnoreDataMember]
         public override EventId EventId => EventId.MakeClientResponseEventId(this.ClientId, this.RequestId);
     }
 }

src/DurableTask.Netherite/OrchestrationService/NetheriteConfigurationException.cs

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+
+    /// <summary>
+    /// An exception that indicates configuration errors for Netherite.
+    /// </summary>
+    [Serializable()]
+    public class NetheriteConfigurationException : System.Exception
+    {
+        public NetheriteConfigurationException() : base() { }
+        public NetheriteConfigurationException(string message) : base(message) { }
+        public NetheriteConfigurationException(string message, System.Exception inner) : base(message, inner) { }
+
+        protected NetheriteConfigurationException(System.Runtime.Serialization.SerializationInfo info,
+         System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+    }
+}

src/DurableTask.Netherite/OrchestrationService/NetheriteOrchestrationService.cs

@@ -10,6 +10,7 @@ namespace DurableTask.Netherite
     using DurableTask.Netherite.Faster;
     using DurableTask.Netherite.Scaling;
     using Microsoft.Azure.Storage;
+    using Microsoft.Extensions.DependencyInjection;
     using Microsoft.Extensions.Logging;
     using Newtonsoft.Json;
     using System;
@@ -29,8 +30,17 @@ namespace DurableTask.Netherite
         DurableTask.Netherite.IOrchestrationServiceQueryClient,
         TransportAbstraction.IHost
     {
-        readonly TransportConnectionString.StorageChoices configuredStorage;
-        readonly TransportConnectionString.TransportChoices configuredTransport;
+        /// <summary>
+        /// The type of transport layer that was configured.
+        /// </summary>
+        public TransportChoices TransportChoice { get; }
+
+        /// <summary>
+        /// The type of storage layer that was configured.
+        /// </summary>
+        public StorageChoices StorageChoice { get; }
+
+
         readonly ITransportLayer transport;
         readonly IStorageLayer storage;
 
@@ -43,6 +53,11 @@ namespace DurableTask.Netherite
         /// </summary>
         public const string LoggerCategoryName = "DurableTask.Netherite";
 
+        public ITransportLayer TransportLayer => this.transport;
+        internal IStorageLayer StorageLayer => this.storage;
+
+        public IServiceProvider ServiceProvider { get; }
+
         CancellationTokenSource serviceShutdownSource;
         Exception startupException;
         Timer threadWatcher;
@@ -88,15 +103,24 @@ namespace DurableTask.Netherite
 #else
             string configuration = "Release";
 #endif
-            return $"NetheriteOrchestrationService on {this.configuredTransport}Transport and {this.configuredStorage}Storage, {configuration} build";
+            return $"NetheriteOrchestrationService on {this.Settings.TransportChoice}Transport and {this.Settings.StorageChoice}Storage, {configuration} build";
         }
 
         /// <summary>
         /// Creates a new instance of the OrchestrationService with default settings
         /// </summary>
         public NetheriteOrchestrationService(NetheriteOrchestrationServiceSettings settings, ILoggerFactory loggerFactory)
+            : this(settings, loggerFactory, null)
+        {
+        }
+        
+        /// <summary>
+        /// Creates a new instance of the OrchestrationService with default settings
+        /// </summary>
+        public NetheriteOrchestrationService(NetheriteOrchestrationServiceSettings settings, ILoggerFactory loggerFactory, IServiceProvider serviceProvider)
         {
             this.LoggerFactory = loggerFactory;
+            this.ServiceProvider = serviceProvider;
             this.Settings = settings;
             this.TraceHelper = new OrchestrationServiceTraceHelper(loggerFactory, settings.LogLevelLimit, settings.WorkerId, settings.HubName);
             this.workItemTraceHelper = new WorkItemTraceHelper(loggerFactory, settings.WorkItemLogLevelLimit, settings.HubName);
@@ -104,42 +128,57 @@ namespace DurableTask.Netherite
             try
             {
                 this.TraceHelper.TraceProgress("Reading configuration for transport and storage layers");
-                TransportConnectionString.Parse(this.Settings.ResolvedTransportConnectionString, out this.configuredStorage, out this.configuredTransport);
-                
-                // determine a storage account name to be used for tracing
-                this.StorageAccountName = this.configuredStorage == TransportConnectionString.StorageChoices.Memory
-                    ? "Memory"
-                    : CloudStorageAccount.Parse(this.Settings.ResolvedStorageConnectionString).Credentials.AccountName;
-                this.TraceHelper.StorageAccountName = this.workItemTraceHelper.StorageAccountName = this.StorageAccountName;
 
-                this.TraceHelper.TraceCreated(Environment.ProcessorCount, this.configuredTransport, this.configuredStorage);
-
-                switch (this.configuredStorage)
+                if (!settings.ResolutionComplete)
                 {
-                    case TransportConnectionString.StorageChoices.Memory:
+                    throw new NetheriteConfigurationException("settings must be validated before constructing orchestration service");
+                }
+
+                // determine a storage account name to be used for tracing
+                this.StorageAccountName = this.Settings.StorageAccountName;
+
+                this.TraceHelper.TraceCreated(Environment.ProcessorCount, this.Settings.TransportChoice, this.Settings.StorageChoice);
+
+                // construct the storage layer
+                switch (this.Settings.StorageChoice)
+                {
+                    case StorageChoices.Memory:
                         this.storage = new MemoryStorageLayer(this.Settings, this.TraceHelper.Logger);
                         break;
 
-                    case TransportConnectionString.StorageChoices.Faster:
+                    case StorageChoices.Faster:
                         this.storage = new FasterStorageLayer(this.Settings, this.TraceHelper, this.LoggerFactory);
                         break;
 
-                    default:
-                        throw new NotImplementedException("no such storage choice");
+                    case StorageChoices.Custom:
+                        var storageLayerFactory = this.ServiceProvider?.GetService<IStorageLayerFactory>();
+                        if (storageLayerFactory == null)
+                        {
+                            throw new NetheriteConfigurationException("could not find injected IStorageLayerFactory");
+                        }
+                        this.storage = storageLayerFactory.Create(this);
+                        break;
                 }
-
-                switch (this.configuredTransport)
+          
+                // construct the transport layer
+                switch (this.Settings.TransportChoice)
                 {
-                    case TransportConnectionString.TransportChoices.SingleHost:
+                    case TransportChoices.SingleHost:
                         this.transport = new SingleHostTransport.SingleHostTransportLayer(this, settings, this.storage, this.TraceHelper.Logger);
                         break;
 
-                    case TransportConnectionString.TransportChoices.EventHubs:
+                    case TransportChoices.EventHubs:
                         this.transport = new EventHubsTransport.EventHubsTransport(this, settings, this.storage, loggerFactory);
                         break;
 
-                    default:
-                        throw new NotImplementedException("no such transport choice");
+                    case TransportChoices.Custom:
+                        var transportLayerFactory = this.ServiceProvider?.GetService<ITransportLayerFactory>();
+                        if (transportLayerFactory == null)
+                        {
+                            throw new NetheriteConfigurationException("could not find injected ITransportLayerFactory");
+                        }
+                        this.transport = transportLayerFactory.Create(this);
+                        break;
                 }
 
                 this.workItemStopwatch.Start();
@@ -168,19 +207,24 @@ namespace DurableTask.Netherite
         /// <returns>true if autoscaling is supported, false otherwise</returns>
         public bool TryGetScalingMonitor(out ScalingMonitor monitor)
         {
-            if (this.configuredStorage == TransportConnectionString.StorageChoices.Faster
-                && this.configuredTransport == TransportConnectionString.TransportChoices.EventHubs)
+            if (this.Settings.StorageChoice == StorageChoices.Faster
+                && this.Settings.TransportChoice == TransportChoices.EventHubs)
             {
                 try
                 {
+                    ILoadPublisherService loadPublisher = string.IsNullOrEmpty(this.Settings.LoadInformationAzureTableName) ?
+                        new AzureBlobLoadPublisher(this.Settings.BlobStorageConnection, this.Settings.HubName)
+                        : new AzureTableLoadPublisher(this.Settings.TableStorageConnection, this.Settings.LoadInformationAzureTableName, this.Settings.HubName);
+
                     monitor = new ScalingMonitor(
-                        this.Settings.ResolvedStorageConnectionString,
-                        this.Settings.ResolvedTransportConnectionString,
+                        loadPublisher,
+                        this.Settings.EventHubsConnection,
                         this.Settings.LoadInformationAzureTableName,
                         this.Settings.HubName,
                         this.TraceHelper.TraceScaleRecommendation,
                         this.TraceHelper.TraceProgress,
                         this.TraceHelper.TraceError);
+
                     return true;
                 }
                 catch (Exception e)

src/DurableTask.Netherite/OrchestrationService/NetheriteOrchestrationServiceSettings.cs

@@ -4,6 +4,7 @@
 namespace DurableTask.Netherite
 {
     using System;
+    using System.Runtime;
     using DurableTask.Core;
     using FASTER.core;
     using Microsoft.Extensions.Logging;
@@ -28,22 +29,11 @@ namespace DurableTask.Netherite
 
         /// <summary>
         /// Gets or sets the name for resolving the Eventhubs namespace connection string.
-        /// Alternatively, may contain special strings specifying the use of the emulator.
+        /// Pseudo-connection-strings "Memory" or "SingleHost" can be used to configure
+        /// in-memory emulation, or single-host configuration, respectively.
         /// </summary>
         public string EventHubsConnectionName { get; set; } = "EventHubsConnection";
 
-        /// <summary>
-        /// The resolved storage connection string. Is never serialized or deserialized.
-        /// </summary>
-        [JsonIgnore]
-        public string ResolvedStorageConnectionString { get; set; }
-
-        /// <summary>
-        /// The resolved event hubs connection string. Is never serialized or deserialized.
-        /// </summary>
-        [JsonIgnore]
-        public string ResolvedTransportConnectionString { get; set; }
-
         /// <summary>
         /// Gets or sets the identifier for the current worker.
         /// </summary>
@@ -172,20 +162,6 @@ namespace DurableTask.Netherite
         /// </summary>
         public int PackPartitionTaskMessages { get; set; } = 100;
 
-        /// <summary>
-        /// A name for resolving a storage connection string to be used specifically for the page blobs, or null if page blobs are to be stored in the default account.
-        /// </summary>
-        public string PageBlobStorageConnectionName { get; set; } = null;
-
-        /// <summary>
-        /// The resolved page blob storage connection string, or null if page blobs are to be stored in the default account. Is never serialized or deserialized.
-        /// </summary>
-        [JsonIgnore]
-        public string ResolvedPageBlobStorageConnectionString { get; set; }
-
-        [JsonIgnore]
-        internal bool UseSeparatePageBlobStorage => !string.IsNullOrEmpty(this.ResolvedPageBlobStorageConnectionString);
-
         /// <summary>
         /// Allows attaching additional checkers and debuggers during testing.
         /// </summary>
@@ -241,67 +217,143 @@ namespace DurableTask.Netherite
         [JsonConverter(typeof(StringEnumConverter))]
         public LogLevel LogLevelLimit { get; set; } = LogLevel.Debug;
 
+        #region Compatibility Shim
+
+        /// <summary>
+        /// The resolved storage connection string. Is never serialized or deserialized.
+        /// </summary>
+        [JsonIgnore]
+        [Obsolete("connections should be resolved by calling settings.Validate(ConnectionResolver resolver)")]
+        public string ResolvedStorageConnectionString { get; set; }
+
+        /// <summary>
+        /// The resolved event hubs connection string. Is never serialized or deserialized.
+        /// </summary>
+        [JsonIgnore]
+        [Obsolete("connections should be resolved by calling settings.Validate(ConnectionResolver resolver)")]
+        public string ResolvedTransportConnectionString { get; set; }
+
+        /// <summary>
+        /// A name for resolving a storage connection string to be used specifically for the page blobs, or null if page blobs are to be stored in the default account.
+        /// </summary>
+        [JsonProperty(DefaultValueHandling = DefaultValueHandling.Ignore)]
+        [Obsolete("connections should be resolved by calling settings.Validate(ConnectionResolver resolver)")]
+        public string PageBlobStorageConnectionName { get; set; } = null;
+
+        /// <summary>
+        /// The resolved page blob storage connection string, or null if page blobs are to be stored in the default account. Is never serialized or deserialized.
+        /// </summary>
+        [JsonIgnore]
+        [Obsolete("connections should be resolved by calling settings.Validate(ConnectionResolver resolver)")]
+        public string ResolvedPageBlobStorageConnectionString { get; set; }
+
+        class CompatibilityResolver : ConnectionResolver
+        {
+            readonly Func<string, string> nameResolver;
+
+            CompatibilityResolver(Func<string, string> nameResolver)
+            {
+                this.nameResolver = nameResolver;
+            }
+
+            public override ConnectionInfo ResolveConnectionInfo(string taskHub, string connectionName, ResourceType recourceType)
+            {
+                throw new NotImplementedException();
+            }
+
+            public override void ResolveLayerConfiguration(string connectionName, out StorageChoices storageChoice, out TransportChoices transportChoice)
+            {
+                throw new NotImplementedException();
+            }
+        }
+
+        #endregion
+
+        #region Parameters that are set during resolution
+
+        /// <summary>
+        /// The type of storage layer to be used
+        /// </summary>
+        [JsonIgnore]
+        public StorageChoices StorageChoice { get; protected set; }
+
+        /// <summary>
+        /// The type of transport layer to be used
+        /// </summary>
+        [JsonIgnore]
+        public TransportChoices TransportChoice { get; protected set; }
+
+        /// <summary>
+        /// The connection information for Azure Storage blobs.
+        /// If not explicitly set, this is populated during validation by resolving <see cref="StorageConnectionName"/>.
+        /// </summary>
+        [JsonIgnore]
+        public ConnectionInfo BlobStorageConnection { get; protected set; }
+
+        /// <summary>
+        /// The connection information for Azure Storage tables.
+        /// If not explicitly set, this is populated during validation by resolving <see cref="StorageConnectionName"/>.
+        /// </summary>
+        [JsonIgnore]
+        public ConnectionInfo TableStorageConnection { get; protected set; }
+
+        /// <summary>
+        /// The connection information for the event hubs namespace.
+        /// If not explicitly set, this is populated during validation by resolving <see cref="EventHubsConnectionName"/>.
+        /// </summary>
+        [JsonIgnore]
+        public ConnectionInfo EventHubsConnection { get; protected set; }
+
+        /// <summary>
+        /// The connection information for Azure Storage page blobs. 
+        ///This is usually null, which means the same <see cref="BlobStorageConnection"/> should be used for page blobs also.
+        /// </summary>
+        [JsonIgnore]
+        public ConnectionInfo PageBlobStorageConnection { get; protected set; }
+
+        /// <summary>
+        /// Whether the storage layer was configured to use a different connection for page blobs than for other blobs
+        /// </summary>
+        [JsonIgnore]
+        internal bool UseSeparatePageBlobStorage => this.PageBlobStorageConnection != null;
+
+        [JsonIgnore]
+        public string StorageAccountName
+            => this.StorageChoice == StorageChoices.Memory ? "Memory" : this.BlobStorageConnection.ResourceName;
+
+        /// <summary>
+        /// Whether the settings have been validated and resolved
+        /// </summary>
+        [JsonIgnore]
+        public bool ResolutionComplete { get; protected set; }
+
+        #endregion
+
         /// <summary>
         /// Validates the settings, throwing exceptions if there are issues.
         /// </summary>
         /// <param name="nameResolver">Optionally, a resolver for connection names.</param>
-        public void Validate(Func<string, string> nameResolver = null)
+        public void Validate(Func<string, string> connectionNameToConnectionString = null)
+        {
+            this.Validate(new CompatibilityConnectionResolver(this, connectionNameToConnectionString));
+        }
+
+        /// <summary>
+        /// Validates the settings and resolves the connections, throwing exceptions if there are issues.
+        /// </summary>
+        /// <param name="resolver">A connection resolver.</param>
+        public void Validate(ConnectionResolver resolver)
         {
             if (string.IsNullOrEmpty(this.HubName))
             {
-                throw new InvalidOperationException($"Must specify {nameof(this.HubName)} for Netherite storage provider.");
-            }
-
-            if (this.PartitionCount < 1 || this.PartitionCount > 32)
-            {
-                throw new ArgumentOutOfRangeException(nameof(this.PartitionCount));
+                throw new NetheriteConfigurationException($"Must specify {nameof(this.HubName)} for Netherite storage provider.");
             }
 
             ValidateTaskhubName(this.HubName);
 
-            if (string.IsNullOrEmpty(this.ResolvedTransportConnectionString))
+            if (this.PartitionCount < 1 || this.PartitionCount > 32)
             {
-                if (string.IsNullOrEmpty(this.EventHubsConnectionName))
-                {
-                    throw new InvalidOperationException($"Must specify {nameof(this.EventHubsConnectionName)} for Netherite storage provider.");
-                }
-
-                if (TransportConnectionString.IsPseudoConnectionString(this.EventHubsConnectionName))
-                {
-                    this.ResolvedTransportConnectionString = this.EventHubsConnectionName;
-                }
-                else
-                {
-                    if (nameResolver == null)
-                    {
-                        throw new InvalidOperationException($"Must either specify {nameof(this.ResolvedTransportConnectionString)}, or specify {nameof(this.EventHubsConnectionName)} and provide a nameResolver, to construct Netherite storage provider.");
-                    }
-
-                    this.ResolvedTransportConnectionString = nameResolver(this.EventHubsConnectionName);
-
-                    if (string.IsNullOrEmpty(this.ResolvedTransportConnectionString))
-                    {
-                        throw new InvalidOperationException($"Could not resolve {nameof(this.EventHubsConnectionName)}:{this.EventHubsConnectionName} for Netherite storage provider.");
-                    }
-                }
-            }
-
-            TransportConnectionString.Parse(this.ResolvedTransportConnectionString, out var storage, out var transport);
-
-            if (transport == TransportConnectionString.TransportChoices.EventHubs)
-            {
-                // validates the connection string
-                TransportConnectionString.EventHubsNamespaceName(this.ResolvedTransportConnectionString);
-            }
-
-            if (storage == TransportConnectionString.StorageChoices.Memory)
-            {
-                this.ResolvedStorageConnectionString = null;
-                this.ResolvedPageBlobStorageConnectionString = null;
-            }
-            else
-            {
-                this.ValidateAzureStorageConnectionStrings(nameResolver);
+                throw new ArgumentOutOfRangeException(nameof(this.PartitionCount));
             }
 
             if (this.MaxConcurrentOrchestratorFunctions <= 0)
@@ -313,78 +365,90 @@ namespace DurableTask.Netherite
             {
                 throw new ArgumentOutOfRangeException(nameof(this.MaxConcurrentActivityFunctions));
             }
-        }
 
-        public void ValidateAzureStorageConnectionStrings(Func<string, string> nameResolver)
-        {
-            if (string.IsNullOrEmpty(this.ResolvedStorageConnectionString))
+            resolver.ResolveLayerConfiguration(this.EventHubsConnectionName, out var storage, out var transport);
+            this.StorageChoice = storage;
+            this.TransportChoice = transport;
+
+            if (this.TransportChoice == TransportChoices.EventHubs)
             {
-                if (nameResolver == null)
+                // we need a valid event hubs connection
+
+                if (string.IsNullOrEmpty(this.EventHubsConnectionName) && resolver is ConnectionNameToConnectionStringResolver)
                 {
-                    throw new InvalidOperationException($"Must either specify {nameof(this.ResolvedStorageConnectionString)}, or specify {nameof(this.StorageConnectionName)} and provide a nameResolver, to construct Netherite storage provider.");
+                    throw new NetheriteConfigurationException($"Must specify {nameof(this.EventHubsConnectionName)} for Netherite storage provider.");
                 }
-
-                if (string.IsNullOrEmpty(this.StorageConnectionName))
-                {
-                    throw new InvalidOperationException($"Must specify {nameof(this.StorageConnectionName)} for Netherite storage provider.");
-                }
-
-                this.ResolvedStorageConnectionString = nameResolver(this.StorageConnectionName);
-
-                if (string.IsNullOrEmpty(this.ResolvedStorageConnectionString))
-                {
-                    throw new InvalidOperationException($"Could not resolve {nameof(this.StorageConnectionName)}:{this.StorageConnectionName} for Netherite storage provider.");
-                }
-            }
-
-            if (string.IsNullOrEmpty(this.ResolvedPageBlobStorageConnectionString)
-                && !string.IsNullOrEmpty(this.PageBlobStorageConnectionName))
-            {
-                if (nameResolver == null)
-                {
-                    throw new InvalidOperationException($"Must either specify {nameof(this.ResolvedPageBlobStorageConnectionString)}, or specify {nameof(this.PageBlobStorageConnectionName)} and provide a nameResolver, to construct Netherite storage provider.");
-                }
-
-                this.ResolvedPageBlobStorageConnectionString = nameResolver(this.PageBlobStorageConnectionName);
-
-                if (string.IsNullOrEmpty(this.ResolvedPageBlobStorageConnectionString))
-                {
-                    throw new InvalidOperationException($"Could not resolve {nameof(this.PageBlobStorageConnectionName)}:{this.PageBlobStorageConnectionName} for Netherite storage provider.");
-                }
-            }
-
-            // make sure the connection string can be parsed correctly
-            try
-            {
-                Microsoft.Azure.Storage.CloudStorageAccount.Parse(this.ResolvedStorageConnectionString);
-            }
-            catch (Exception e)
-            {
-                throw new FormatException($"Could not parse the specified storage connection string for Netherite storage provider", e);
-            }
-
-            if (!string.IsNullOrEmpty(this.ResolvedPageBlobStorageConnectionString))
-            {
-                // make sure the connection string can be parsed correctly
                 try
                 {
-                    Microsoft.Azure.Storage.CloudStorageAccount.Parse(this.ResolvedPageBlobStorageConnectionString);
+                    this.EventHubsConnection = resolver.ResolveConnectionInfo(this.HubName, this.EventHubsConnectionName, ConnectionResolver.ResourceType.EventHubsNamespace);
                 }
                 catch (Exception e)
                 {
-                    throw new FormatException($"Could not parse the specified page blob storage connection string for Netherite storage provider", e);
+                    throw new NetheriteConfigurationException($"Could not resolve {nameof(this.EventHubsConnectionName)}={this.EventHubsConnectionName} to create an eventhubs connection for Netherite storage provider: {e.Message}", e);
+                }
+                if (this.EventHubsConnection == null)
+                {
+                    throw new NetheriteConfigurationException($"Could not resolve {nameof(this.EventHubsConnectionName)}={this.EventHubsConnectionName} to create an eventhubs connection for Netherite storage provider.");
                 }
             }
+
+            if (this.StorageChoice == StorageChoices.Faster || this.TransportChoice == TransportChoices.EventHubs)
+            {
+                // we need a valid blob storage connection
+
+                if (string.IsNullOrEmpty(this.StorageConnectionName) && resolver is ConnectionNameToConnectionStringResolver)
+                {
+                    throw new NetheriteConfigurationException($"Must specify {nameof(this.StorageConnectionName)} for Netherite storage provider.");
+                }
+                try
+                {
+                    this.BlobStorageConnection = resolver.ResolveConnectionInfo(this.HubName, this.StorageConnectionName, ConnectionResolver.ResourceType.BlobStorage);
+                }
+                catch (Exception e)
+                {
+                    throw new NetheriteConfigurationException($"Could not resolve {nameof(this.StorageConnectionName)}={this.StorageConnectionName} to create a blob storage connection for Netherite storage provider: {e.Message}", e);
+                }
+                if (this.BlobStorageConnection == null)
+                {
+                    throw new NetheriteConfigurationException($"Could not resolve {nameof(this.StorageConnectionName)}={this.StorageConnectionName} to create a blob storage connection for Netherite storage provider.");
+                }
+            }
+
+            if (this.StorageChoice == StorageChoices.Faster && this.LoadInformationAzureTableName != null)
+            {
+                // we need a valid table storage connection
+                try
+                {
+                    this.TableStorageConnection = resolver.ResolveConnectionInfo(this.HubName, this.StorageConnectionName, ConnectionResolver.ResourceType.TableStorage);
+                }
+                catch (Exception e)
+                {
+                    throw new NetheriteConfigurationException($"Could not resolve {nameof(this.StorageConnectionName)}={this.StorageConnectionName} to create a table storage connection for Netherite storage provider: {e.Message}", e);
+                }
+                if (this.TableStorageConnection == null)
+                {
+                    throw new NetheriteConfigurationException($"Could not resolve {nameof(this.StorageConnectionName)}={this.StorageConnectionName} to create a table storage connection for Netherite storage provider.");
+                }
+            }
+
+            if (this.StorageChoice == StorageChoices.Faster)
+            {
+                // some custom resolvers may specify a separate page blob connection, but usually this will be null
+                this.PageBlobStorageConnection = resolver.ResolveConnectionInfo(this.HubName, this.StorageConnectionName, ConnectionResolver.ResourceType.PageBlobStorage);
+            }
+
+            // we have completed validation and resolution
+            this.ResolutionComplete = true;
         }
 
-        const int MinTaskHubNameSize = 1;
+        const int MinTaskHubNameSize = 3;
         const int MaxTaskHubNameSize = 45;
 
         public static void ValidateTaskhubName(string taskhubName)
         {
             if (taskhubName.Length < MinTaskHubNameSize || taskhubName.Length > MaxTaskHubNameSize)
             {
-                throw new ArgumentException(GetTaskHubErrorString(taskhubName));
+                throw new NetheriteConfigurationException(GetTaskHubErrorString(taskhubName));
             }
 
             try
@@ -394,7 +458,7 @@ namespace DurableTask.Netherite
             }
             catch (ArgumentException e)
             {
-                throw new ArgumentException(GetTaskHubErrorString(taskhubName), e);
+                throw new NetheriteConfigurationException(GetTaskHubErrorString(taskhubName), e);
             }
         }
 

src/DurableTask.Netherite/OrchestrationService/TransportConnectionString.cs

@@ -14,48 +14,12 @@ namespace DurableTask.Netherite
     /// </summary>
     public static class TransportConnectionString
     {
-        /// <summary>
-        /// Configuration options for the storage component
-        /// </summary>
-        public enum StorageChoices
-        {
-            /// <summary>
-            /// Does not store any state to durable storage, just keeps it in memory. 
-            /// Intended for testing scenarios.
-            /// </summary>
-            Memory = 0,
-
-            /// <summary>
-            /// Uses the Faster key-value store.
-            /// </summary>
-            Faster = 1,
-        }
-
-        /// <summary>
-        /// Configuration options for the transport component
-        /// </summary>
-        public enum TransportChoices
-        {
-            /// <summary>
-            /// Passes messages through memory and puts all partitions on a single host
-            /// Intended for testing scenarios.
-            /// </summary>
-            SingleHost = 0,
-
-            /// <summary>
-            /// Passes messages through eventhubs; can distribute over multiple machines via
-            /// the eventhubs EventProcessor.
-            /// </summary>
-            EventHubs = 1,
-        }
-
-
         /// <summary>
         /// Determines the components to use given a transport connection string.
         /// </summary>
         public static bool IsPseudoConnectionString(string connectionString)
         {
-            switch (connectionString.ToLowerInvariant().Trim())
+            switch ((connectionString ?? "").ToLowerInvariant().Trim())
             {
                 case "memory":
                 case "singlehost":

src/DurableTask.Netherite/Scaling/AzureBlobLoadPublisher.cs

@@ -17,7 +17,7 @@ namespace DurableTask.Netherite.Scaling
     class AzureBlobLoadPublisher : ILoadPublisherService
     {
         readonly string taskHubName;
-        readonly CloudBlobContainer blobContainer;
+        readonly Task<CloudBlobContainer> blobContainer;
 
         readonly static JsonSerializerSettings serializerSettings = new JsonSerializerSettings() 
         {
@@ -27,13 +27,18 @@ namespace DurableTask.Netherite.Scaling
 
         int? numPartitions;
 
-        public AzureBlobLoadPublisher(string connectionString, string taskHubName)
+        public AzureBlobLoadPublisher(ConnectionInfo connectionInfo, string taskHubName)
         {
-            var cloudStorageAccount = CloudStorageAccount.Parse(connectionString);
+            this.blobContainer = this.GetBlobContainer(connectionInfo, taskHubName);
+            this.taskHubName = taskHubName;
+        }
+
+        async Task<CloudBlobContainer> GetBlobContainer(ConnectionInfo connectionInfo, string taskHubName)
+        {
+            var cloudStorageAccount = await connectionInfo.GetAzureStorageV11AccountAsync();
             CloudBlobClient serviceClient = cloudStorageAccount.CreateCloudBlobClient();
             string containerName = BlobManager.GetContainerName(taskHubName);
-            this.blobContainer = serviceClient.GetContainerReference(containerName);
-            this.taskHubName = taskHubName;
+            return serviceClient.GetContainerReference(containerName);
         }
 
         public TimeSpan PublishInterval => TimeSpan.FromSeconds(10);
@@ -46,12 +51,12 @@ namespace DurableTask.Netherite.Scaling
 
         public Task PublishAsync(Dictionary<uint, PartitionLoadInfo> info, CancellationToken cancellationToken)
         {
-            Task UploadPartitionInfo(uint partitionId, PartitionLoadInfo loadInfo)
+            async Task UploadPartitionInfo(uint partitionId, PartitionLoadInfo loadInfo)
             {
-                var blobDirectory = this.blobContainer.GetDirectoryReference($"p{partitionId:D2}");
+                var blobDirectory = (await this.blobContainer).GetDirectoryReference($"p{partitionId:D2}");
                 var blob = blobDirectory.GetBlockBlobReference("loadinfo.json");
                 var json = JsonConvert.SerializeObject(loadInfo, Formatting.Indented, serializerSettings);
-                return blob.UploadTextAsync(json, cancellationToken);
+                await blob.UploadTextAsync(json, cancellationToken);
             }
 
             List<Task> tasks = info.Select(kvp => UploadPartitionInfo(kvp.Key, kvp.Value)).ToList();
@@ -87,7 +92,7 @@ namespace DurableTask.Netherite.Scaling
             {
                 // determine number of partitions of taskhub
                 var info = await this.ReadJsonBlobAsync<Netherite.Abstractions.TaskhubParameters>(
-                    this.blobContainer.GetBlockBlobReference("taskhubparameters.json"),
+                    (await this.blobContainer).GetBlockBlobReference("taskhubparameters.json"),
                     throwIfNotFound: true,
                     throwOnParseError: true,
                     cancellationToken).ConfigureAwait(false);
@@ -98,7 +103,7 @@ namespace DurableTask.Netherite.Scaling
             async Task<(uint, PartitionLoadInfo)> DownloadPartitionInfo(uint partitionId)
             {
                 PartitionLoadInfo info = await this.ReadJsonBlobAsync<PartitionLoadInfo>(
-                    this.blobContainer.GetDirectoryReference($"p{partitionId:D2}").GetBlockBlobReference("loadinfo.json"), 
+                    (await this.blobContainer).GetDirectoryReference($"p{partitionId:D2}").GetBlockBlobReference("loadinfo.json"), 
                     throwIfNotFound: false, 
                     throwOnParseError: true,
                     cancellationToken).ConfigureAwait(false);
@@ -116,7 +121,7 @@ namespace DurableTask.Netherite.Scaling
             {
                 // determine number of partitions of taskhub
                 var info = await this.ReadJsonBlobAsync<Netherite.Abstractions.TaskhubParameters>(
-                    this.blobContainer.GetBlockBlobReference("taskhubparameters.json"),
+                    (await this.blobContainer).GetBlockBlobReference("taskhubparameters.json"),
                     throwIfNotFound: false,
                     throwOnParseError: false,
                     cancellationToken).ConfigureAwait(false);
@@ -133,7 +138,7 @@ namespace DurableTask.Netherite.Scaling
 
             async Task DeletePartitionInfo(uint partitionId)
             {
-                var blob = this.blobContainer.GetDirectoryReference($"p{partitionId:D2}").GetBlockBlobReference("loadinfo.json");
+                var blob = (await this.blobContainer).GetDirectoryReference($"p{partitionId:D2}").GetBlockBlobReference("loadinfo.json");
                 await BlobUtils.ForceDeleteAsync(blob).ConfigureAwait(false);
             }
 

src/DurableTask.Netherite/Scaling/AzureTableLoadPublisher.cs

@@ -19,9 +19,9 @@ namespace DurableTask.Netherite.Scaling
         readonly TableClient table;
         readonly string taskHubName;
 
-        public AzureTableLoadPublisher(string connectionString, string tableName, string taskHubName)
+        public AzureTableLoadPublisher(ConnectionInfo connectionInfo, string tableName, string taskHubName)
         {
-            this.table = new TableClient(connectionString, tableName); 
+            this.table = connectionInfo.GetAzureStorageV12TableClientAsync(tableName, CancellationToken.None); 
             this.taskHubName = taskHubName;
         }
 

src/DurableTask.Netherite/Scaling/ScalingMonitor.cs

@@ -18,19 +18,16 @@ namespace DurableTask.Netherite.Scaling
     /// </summary>
     public class ScalingMonitor
     {
-        readonly string storageConnectionString;
-        readonly string eventHubsConnectionString;
+        readonly ConnectionInfo eventHubsConnection;
         readonly string partitionLoadTableName;
         readonly string taskHubName;
-        readonly TransportConnectionString.TransportChoices configuredTransport;
+        readonly ILoadPublisherService loadPublisher;
 
         // public logging actions to enable collection of scale-monitor-related logging within the Netherite infrastructure
         public Action<string, int, string> RecommendationTracer { get; }
         public Action<string> InformationTracer { get; }
         public Action<string, Exception> ErrorTracer { get; }
 
-        readonly ILoadPublisherService loadPublisher;
-
         /// <summary>
         /// The name of the taskhub.
         /// </summary>
@@ -39,13 +36,13 @@ namespace DurableTask.Netherite.Scaling
         /// <summary>
         /// Creates an instance of the scaling monitor, with the given parameters.
         /// </summary>
-        /// <param name="storageConnectionString">The storage connection string.</param>
-        /// <param name="eventHubsConnectionString">The connection string for the transport layer.</param>
+        /// <param name="storageConnection">The storage connection info.</param>
+        /// <param name="eventHubsConnection">The connection info for event hubs.</param>
         /// <param name="partitionLoadTableName">The name of the storage table with the partition load information.</param>
         /// <param name="taskHubName">The name of the taskhub.</param>
         public ScalingMonitor(
-            string storageConnectionString,
-            string eventHubsConnectionString,
+            ILoadPublisherService loadPublisher,
+            ConnectionInfo eventHubsConnection,
             string partitionLoadTableName,
             string taskHubName,
             Action<string, int, string> recommendationTracer,
@@ -56,21 +53,10 @@ namespace DurableTask.Netherite.Scaling
             this.InformationTracer = informationTracer;
             this.ErrorTracer = errorTracer;
 
-            this.storageConnectionString = storageConnectionString;
-            this.eventHubsConnectionString = eventHubsConnectionString;
+            this.loadPublisher = loadPublisher;
+            this.eventHubsConnection = eventHubsConnection;
             this.partitionLoadTableName = partitionLoadTableName;
             this.taskHubName = taskHubName;
-
-            TransportConnectionString.Parse(eventHubsConnectionString, out _, out this.configuredTransport);
-
-            if (!string.IsNullOrEmpty(partitionLoadTableName))
-            {
-                this.loadPublisher = new AzureTableLoadPublisher(storageConnectionString, partitionLoadTableName, taskHubName);
-            }
-            else
-            {
-                this.loadPublisher = new AzureBlobLoadPublisher(storageConnectionString, taskHubName);
-            }
         }
 
         /// <summary>
@@ -230,25 +216,23 @@ namespace DurableTask.Netherite.Scaling
             // next, check if any of the entries are not current, in the sense that their input queue position
             // does not match the latest queue position
 
-            if (this.configuredTransport == TransportConnectionString.TransportChoices.EventHubs)
+           
+            List<long> positions = await Netherite.EventHubsTransport.EventHubsConnections.GetQueuePositionsAsync(this.eventHubsConnection, EventHubsTransport.PartitionHub).ConfigureAwait(false);
+
+            if (positions == null)
             {
-                List<long> positions = await Netherite.EventHubsTransport.EventHubsConnections.GetQueuePositionsAsync(this.eventHubsConnectionString, EventHubsTransport.PartitionHub).ConfigureAwait(false);
+                return "eventhubs is missing";
+            }
 
-                if (positions == null)
+            for (int i = 0; i < positions.Count; i++)
+            {
+                if (!loadInformation.TryGetValue((uint) i, out var loadInfo))
                 {
-                    return "eventhubs is missing";
+                    return $"P{i:D2} has no load information published yet";
                 }
-
-                for (int i = 0; i < positions.Count; i++)
+                if (positions[i] > loadInfo.InputQueuePosition)
                 {
-                    if (!loadInformation.TryGetValue((uint) i, out var loadInfo))
-                    {
-                        return $"P{i:D2} has no load information published yet";
-                    }
-                    if (positions[i] > loadInfo.InputQueuePosition)
-                    {
-                        return $"P{i:D2} has input queue position {loadInfo.InputQueuePosition} which is {positions[(int)i] - loadInfo.InputQueuePosition} behind latest position {positions[i]}";
-                    }
+                    return $"P{i:D2} has input queue position {loadInfo.InputQueuePosition} which is {positions[(int)i] - loadInfo.InputQueuePosition} behind latest position {positions[i]}";
                 }
             }
 
@@ -267,4 +251,4 @@ namespace DurableTask.Netherite.Scaling
             return null;
         }  
     }
-}
+}

src/DurableTask.Netherite/StorageLayer/Faster/AzureBlobs/BlobManager.cs

@@ -24,14 +24,15 @@ namespace DurableTask.Netherite.Faster
     /// </summary>
     partial class BlobManager : ICheckpointManager, ILogCommitManager
     {
+        readonly NetheriteOrchestrationServiceSettings settings;
         readonly uint partitionId;
         readonly CancellationTokenSource shutDownOrTermination;
-        readonly CloudStorageAccount cloudStorageAccount;
-        readonly CloudStorageAccount pageBlobAccount;
         readonly string taskHubPrefix;
 
-        readonly CloudBlobContainer blockBlobContainer;
-        readonly CloudBlobContainer pageBlobContainer;
+        CloudStorageAccount cloudStorageAccount;
+        CloudStorageAccount pageBlobAccount;
+        CloudBlobContainer blockBlobContainer;
+        CloudBlobContainer pageBlobContainer;
         CloudBlockBlob eventLogCommitBlob;
         CloudBlobDirectory pageBlobPartitionDirectory;
         CloudBlobDirectory blockBlobPartitionDirectory;
@@ -191,16 +192,16 @@ namespace DurableTask.Netherite.Faster
 
                 if (taskhubFormat.UseAlternateObjectStore != settings.UseAlternateObjectStore)
                 {
-                    throw new InvalidOperationException("The Netherite configuration setting 'UseAlternateObjectStore' is incompatible with the existing taskhub.");
+                    throw new NetheriteConfigurationException("The Netherite configuration setting 'UseAlternateObjectStore' is incompatible with the existing taskhub.");
                 }
                 if (taskhubFormat.FormatVersion != StorageFormatVersion.Last())
                 {
-                    throw new InvalidOperationException($"The current storage format version (={StorageFormatVersion.Last()}) is incompatible with the existing taskhub (={taskhubFormat.FormatVersion}).");
+                    throw new NetheriteConfigurationException($"The current storage format version (={StorageFormatVersion.Last()}) is incompatible with the existing taskhub (={taskhubFormat.FormatVersion}).");
                 }
             }
             catch (Exception e)
             {
-                throw new InvalidOperationException("The taskhub has an incompatible storage format", e);
+                throw new NetheriteConfigurationException("The taskhub has an incompatible storage format", e);
             }
         }
 
@@ -271,9 +272,7 @@ namespace DurableTask.Netherite.Faster
         /// <param name="errorHandler">A handler for errors encountered in this partition</param>
         /// <param name="psfGroupCount">Number of PSF groups to be created in FASTER</param>
         public BlobManager(
-            CloudStorageAccount storageAccount,
-            CloudStorageAccount pageBlobAccount,
-            string localFilePath,
+            NetheriteOrchestrationServiceSettings settings,
             string taskHubName,
             string taskHubPrefix,
             FaultInjector faultInjector,
@@ -284,10 +283,7 @@ namespace DurableTask.Netherite.Faster
             IPartitionErrorHandler errorHandler,
             int psfGroupCount)
         {
-            this.cloudStorageAccount = storageAccount;
-            this.pageBlobAccount = pageBlobAccount;
-            this.UseLocalFiles = (localFilePath != null);
-            this.LocalFileDirectoryForTestingAndDebugging = localFilePath;
+            this.settings = settings;
             this.ContainerName = GetContainerName(taskHubName);
             this.taskHubPrefix = taskHubPrefix;
             this.FaultInjector = faultInjector;
@@ -295,30 +291,20 @@ namespace DurableTask.Netherite.Faster
             this.CheckpointInfo = new CheckpointInfo();
             this.PsfCheckpointInfos = Enumerable.Range(0, psfGroupCount).Select(ii => new CheckpointInfo()).ToArray();
 
-            if (!this.UseLocalFiles)
+            if (!string.IsNullOrEmpty(settings.UseLocalDirectoryForPartitionStorage))
             {
-                CloudBlobClient serviceClient = this.cloudStorageAccount.CreateCloudBlobClient();
-                this.blockBlobContainer = serviceClient.GetContainerReference(this.ContainerName);
-
-                if (pageBlobAccount == storageAccount)
-                {
-                    this.pageBlobContainer = this.BlockBlobContainer;
-                }
-                else
-                {
-                    serviceClient = this.pageBlobAccount.CreateCloudBlobClient();
-                    this.pageBlobContainer = serviceClient.GetContainerReference(this.ContainerName);
-                }
+                this.UseLocalFiles = true;
+                this.LocalFileDirectoryForTestingAndDebugging = settings.UseLocalDirectoryForPartitionStorage;
+                this.LocalCheckpointManager = new LocalFileCheckpointManager(
+                   this.CheckpointInfo,
+                   this.LocalCheckpointDirectoryPath,
+                   this.GetCheckpointCompletedBlobName());
             }
             else
             {
-                this.LocalCheckpointManager = new LocalFileCheckpointManager(
-                    this.CheckpointInfo,
-                    this.LocalCheckpointDirectoryPath,
-                    this.GetCheckpointCompletedBlobName());
+                this.UseLocalFiles = false;
             }
-
-            this.TraceHelper = new FasterTraceHelper(logger, logLevelLimit, performanceLogger, this.partitionId, this.UseLocalFiles ? "none" : this.cloudStorageAccount.Credentials.AccountName, taskHubName);
+            this.TraceHelper = new FasterTraceHelper(logger, logLevelLimit, performanceLogger, this.partitionId, this.UseLocalFiles ? "none" : this.settings.StorageAccountName, taskHubName);
             this.PartitionErrorHandler = errorHandler;
             this.shutDownOrTermination = CancellationTokenSource.CreateLinkedTokenSource(errorHandler.Token);
         }
@@ -328,7 +314,7 @@ namespace DurableTask.Netherite.Faster
 
         // For testing and debugging with local files
         bool UseLocalFiles { get; }
-        LocalFileCheckpointManager LocalCheckpointManager { get; }
+        LocalFileCheckpointManager LocalCheckpointManager { get; set; }
         string LocalFileDirectoryForTestingAndDebugging { get; }
         string LocalDirectoryPath => $"{this.LocalFileDirectoryForTestingAndDebugging}\\{this.ContainerName}";
         string LocalCheckpointDirectoryPath => $"{this.LocalDirectoryPath}\\chkpts{this.partitionId:D2}";
@@ -351,6 +337,11 @@ namespace DurableTask.Netherite.Faster
         {
             if (this.UseLocalFiles)
             {
+                this.LocalCheckpointManager = new LocalFileCheckpointManager(
+                       this.CheckpointInfo,
+                       this.LocalCheckpointDirectoryPath,
+                       this.GetCheckpointCompletedBlobName());
+
                 Directory.CreateDirectory($"{this.LocalDirectoryPath}\\{this.PartitionFolderName}");
 
                 this.EventLogDevice = Devices.CreateLogDevice($"{this.LocalDirectoryPath}\\{this.PartitionFolderName}\\{EventLogBlobName}");
@@ -365,6 +356,30 @@ namespace DurableTask.Netherite.Faster
             }
             else
             {
+                this.cloudStorageAccount = await this.settings.BlobStorageConnection.GetAzureStorageV11AccountAsync();
+
+                if (this.settings.PageBlobStorageConnection != null)
+                {
+                    this.pageBlobAccount = await this.settings.PageBlobStorageConnection.GetAzureStorageV11AccountAsync();
+                }
+                else
+                {
+                    this.pageBlobAccount = this.cloudStorageAccount;
+                }
+
+                CloudBlobClient serviceClient = this.cloudStorageAccount.CreateCloudBlobClient();
+                this.blockBlobContainer = serviceClient.GetContainerReference(this.ContainerName);
+
+                if (this.pageBlobAccount == this.cloudStorageAccount)
+                {
+                    this.pageBlobContainer = this.BlockBlobContainer;
+                }
+                else
+                {
+                    serviceClient = this.pageBlobAccount.CreateCloudBlobClient();
+                    this.pageBlobContainer = serviceClient.GetContainerReference(this.ContainerName);
+                }
+
                 await this.blockBlobContainer.CreateIfNotExistsAsync();
                 this.blockBlobPartitionDirectory = this.blockBlobContainer.GetDirectoryReference(this.PartitionFolderName);
 
@@ -445,13 +460,13 @@ namespace DurableTask.Netherite.Faster
             await this.LeaseMaintenanceLoopTask; // wait for loop to terminate cleanly
         }
 
-        public static async Task DeleteTaskhubStorageAsync(CloudStorageAccount account, CloudStorageAccount pageBlobAccount, string localFileDirectoryPath, string taskHubName, string pathPrefix)
+        public static async Task DeleteTaskhubStorageAsync(NetheriteOrchestrationServiceSettings settings, string pathPrefix)
         {
-            var containerName = GetContainerName(taskHubName);
+            var containerName = GetContainerName(settings.HubName);
 
-            if (!string.IsNullOrEmpty(localFileDirectoryPath))
+            if (!string.IsNullOrEmpty(settings.UseLocalDirectoryForPartitionStorage))
             {
-                DirectoryInfo di = new DirectoryInfo($"{localFileDirectoryPath}\\{containerName}"); //TODO fine-grained deletion
+                DirectoryInfo di = new DirectoryInfo($"{settings.UseLocalDirectoryForPartitionStorage}\\{containerName}"); //TODO fine-grained deletion
                 if (di.Exists)
                 {
                     di.Delete(true);
@@ -459,8 +474,9 @@ namespace DurableTask.Netherite.Faster
             }
             else
             {
-                async Task DeleteContainerContents(CloudStorageAccount account)
+                async Task DeleteContainerContents(ConnectionInfo connectionInfo)
                 {
+                    var account = await connectionInfo.GetAzureStorageV11AccountAsync();
                     CloudBlobClient serviceClient = account.CreateCloudBlobClient();
                     var blobContainer = serviceClient.GetContainerReference(containerName);
 
@@ -495,11 +511,11 @@ namespace DurableTask.Netherite.Faster
                     // the same container.
                 }
 
-                await DeleteContainerContents(account);
+                await DeleteContainerContents(settings.BlobStorageConnection);
 
-                if (pageBlobAccount != account)
+                if (settings.PageBlobStorageConnection != null)
                 {
-                    await DeleteContainerContents(pageBlobAccount);
+                    await DeleteContainerContents(settings.PageBlobStorageConnection);
                 }
             }
         }

src/DurableTask.Netherite/StorageLayer/Faster/FasterStorageProvider.cs

@@ -22,15 +22,12 @@ namespace DurableTask.Netherite.Faster
         readonly NetheriteOrchestrationServiceSettings settings;
         readonly OrchestrationServiceTraceHelper traceHelper;
 
-        readonly CloudStorageAccount storageAccount;
-        readonly string localFileDirectory;
-        readonly CloudStorageAccount pageBlobStorageAccount;
-
         readonly ILogger logger;
         readonly ILogger performanceLogger;
         readonly MemoryTracker memoryTracker;
-        readonly CloudBlobContainer cloudBlobContainer;
-        readonly CloudBlockBlob taskhubParameters;
+
+        readonly Task<CloudBlobContainer> cloudBlobContainer;
+        readonly Task<CloudBlockBlob> taskhubParameters;
 
         public ILoadPublisherService LoadPublisher { get;}
 
@@ -52,27 +49,8 @@ namespace DurableTask.Netherite.Faster
             this.settings = settings;
             this.traceHelper = traceHelper;
 
-            string connectionString = settings.ResolvedStorageConnectionString;
-            string pageBlobConnectionString = settings.ResolvedPageBlobStorageConnectionString;
-
             this.TestRuntimeAndLoading();
-
-            if (!string.IsNullOrEmpty(settings.UseLocalDirectoryForPartitionStorage))
-            {
-                this.localFileDirectory = settings.UseLocalDirectoryForPartitionStorage;
-            }
-            else
-            {
-                this.storageAccount = CloudStorageAccount.Parse(connectionString);
-            }
-            if (pageBlobConnectionString != connectionString && !string.IsNullOrEmpty(pageBlobConnectionString))
-            {
-                this.pageBlobStorageAccount = CloudStorageAccount.Parse(pageBlobConnectionString);
-            }
-            else
-            {
-                this.pageBlobStorageAccount = this.storageAccount;
-            }
+            
             this.logger = loggerFactory.CreateLogger($"{NetheriteOrchestrationService.LoggerCategoryName}.FasterStorage");
             this.performanceLogger = loggerFactory.CreateLogger($"{NetheriteOrchestrationService.LoggerCategoryName}.FasterStorage.Performance");
 
@@ -83,19 +61,29 @@ namespace DurableTask.Netherite.Faster
                 settings.TestHooks.CacheDebugger.MemoryTracker = this.memoryTracker;
             }
 
-            var blobContainerName = GetContainerName(settings.HubName);
-            var cloudBlobClient = this.storageAccount.CreateCloudBlobClient();
-            this.cloudBlobContainer = cloudBlobClient.GetContainerReference(blobContainerName);
-            this.taskhubParameters = this.cloudBlobContainer.GetBlockBlobReference("taskhubparameters.json");
+            this.cloudBlobContainer = GetBlobContainerAsync();
+            async Task<CloudBlobContainer> GetBlobContainerAsync()
+            {
+                var blobContainerName = GetContainerName(settings.HubName);
+                var cloudBlobClient = (await settings.BlobStorageConnection.GetAzureStorageV11AccountAsync()).CreateCloudBlobClient();
+                return cloudBlobClient.GetContainerReference(blobContainerName);
+            }
+
+            this.taskhubParameters = GetTaskhubParametersAsync();
+            async Task<CloudBlockBlob> GetTaskhubParametersAsync()
+            {
+                var cloudBlobContainer = await this.cloudBlobContainer;
+                return cloudBlobContainer.GetBlockBlobReference("taskhubparameters.json");
+            }
 
             this.traceHelper.TraceProgress("Creating LoadMonitor Service");
             if (!string.IsNullOrEmpty(settings.LoadInformationAzureTableName))
             {
-                this.LoadPublisher = new AzureTableLoadPublisher(settings.ResolvedStorageConnectionString, settings.LoadInformationAzureTableName, settings.HubName);
+                this.LoadPublisher = new AzureTableLoadPublisher(settings.TableStorageConnection, settings.LoadInformationAzureTableName, settings.HubName);
             }
             else
             {
-                this.LoadPublisher = new AzureBlobLoadPublisher(settings.ResolvedStorageConnectionString, settings.HubName);
+                this.LoadPublisher = new AzureBlobLoadPublisher(settings.BlobStorageConnection, settings.HubName);
             }
         }
 
@@ -117,14 +105,15 @@ namespace DurableTask.Netherite.Faster
             // try load the taskhub parameters
             try
             {
-                var jsonText = await this.taskhubParameters.DownloadTextAsync();
+                var blob = await this.taskhubParameters;
+                var jsonText = await blob.DownloadTextAsync();
                 return JsonConvert.DeserializeObject<TaskhubParameters>(jsonText);
             }
             catch (StorageException ex) when (ex.RequestInformation.HttpStatusCode == (int)System.Net.HttpStatusCode.NotFound)
             {
                 if (throwIfNotFound)
                 {
-                    throw new InvalidOperationException($"The specified taskhub does not exist (TaskHub={this.settings.HubName}, StorageConnectionName={this.settings.StorageConnectionName}");
+                    throw new NetheriteConfigurationException($"The specified taskhub does not exist (TaskHub={this.settings.HubName}, StorageConnectionName={this.settings.StorageConnectionName}");
                 }
                 else
                 {
@@ -135,14 +124,14 @@ namespace DurableTask.Netherite.Faster
 
         async Task<bool> IStorageLayer.CreateTaskhubIfNotExistsAsync()
         {
-            bool containerCreated = await this.cloudBlobContainer.CreateIfNotExistsAsync();
+            bool containerCreated = await (await this.cloudBlobContainer).CreateIfNotExistsAsync();
             if (containerCreated)
             {
-                this.traceHelper.TraceProgress($"Created new blob container at {this.cloudBlobContainer.Uri}");
+                this.traceHelper.TraceProgress($"Created new blob container at {this.cloudBlobContainer.Result.Uri}");
             }
             else
             {
-                this.traceHelper.TraceProgress($"Using existing blob container at {this.cloudBlobContainer.Uri}");
+                this.traceHelper.TraceProgress($"Using existing blob container at {this.cloudBlobContainer.Result.Uri}");
             }
 
             var taskHubParameters = new TaskhubParameters()
@@ -166,13 +155,13 @@ namespace DurableTask.Netherite.Faster
                     new JsonSerializerSettings() { TypeNameHandling = TypeNameHandling.None });
 
                 var noOverwrite = AccessCondition.GenerateIfNoneMatchCondition("*");
-                await this.taskhubParameters.UploadTextAsync(jsonText, null, noOverwrite, null, null);
+                await (await this.taskhubParameters).UploadTextAsync(jsonText, null, noOverwrite, null, null);
                 this.traceHelper.TraceProgress("Created new taskhub");
 
                 // zap the partition hub so we start from zero queue positions
-                if (!TransportConnectionString.IsPseudoConnectionString(this.settings.ResolvedTransportConnectionString))
+                if (this.settings.TransportChoice == TransportChoices.EventHubs)
                 {
-                    await EventHubsUtil.DeleteEventHubIfExistsAsync(this.settings.ResolvedTransportConnectionString, EventHubsTransport.PartitionHub);
+                    await EventHubsUtil.DeleteEventHubIfExistsAsync(this.settings.EventHubsConnection, EventHubsTransport.PartitionHub, CancellationToken.None);
                 }
             }
             catch (StorageException e) when (BlobUtils.BlobAlreadyExists(e))
@@ -197,20 +186,20 @@ namespace DurableTask.Netherite.Faster
                 await this.LoadPublisher.DeleteIfExistsAsync(CancellationToken.None).ConfigureAwait(false);
 
                 // delete the parameters file which deletes the taskhub logically
-                await BlobUtils.ForceDeleteAsync(this.taskhubParameters);
+                await BlobUtils.ForceDeleteAsync(await this.taskhubParameters);
 
                 // delete all the files/blobs in the directory/container that represents this taskhub
                 // If this does not complete successfully, some garbage may be left behind.
-                await BlobManager.DeleteTaskhubStorageAsync(this.storageAccount, this.pageBlobStorageAccount, this.localFileDirectory, parameters.TaskhubName, TaskhubPathPrefix(parameters));
+                await BlobManager.DeleteTaskhubStorageAsync(this.settings, TaskhubPathPrefix(parameters));
             }
         }
 
-        public static Task DeleteTaskhubStorageAsync(string connectionString, string pageBlobConnectionString, string localFileDirectory, string taskHubName, string pathPrefix)
-        {
-            var storageAccount = string.IsNullOrEmpty(connectionString) ? null : CloudStorageAccount.Parse(connectionString);
-            var pageBlobAccount = string.IsNullOrEmpty(pageBlobConnectionString) ? storageAccount : CloudStorageAccount.Parse(pageBlobConnectionString);
-            return BlobManager.DeleteTaskhubStorageAsync(storageAccount, pageBlobAccount, localFileDirectory, taskHubName, pathPrefix);
-        }
+        //public static Task DeleteTaskhubStorageAsync(string connectionString, string pageBlobConnectionString, string localFileDirectory, string taskHubName, string pathPrefix)
+        //{
+        //    var storageAccount = string.IsNullOrEmpty(connectionString) ? null : CloudStorageAccount.Parse(connectionString);
+        //    var pageBlobAccount = string.IsNullOrEmpty(pageBlobConnectionString) ? storageAccount : CloudStorageAccount.Parse(pageBlobConnectionString);
+        //    return BlobManager.DeleteTaskhubStorageAsync(storageAccount, pageBlobAccount, localFileDirectory, taskHubName, pathPrefix);
+        //}
 
         IPartitionState IStorageLayer.CreatePartitionState(TaskhubParameters parameters)
         {

src/DurableTask.Netherite/StorageLayer/Faster/PartitionStorage.cs

@@ -14,15 +14,15 @@ namespace DurableTask.Netherite.Faster
 
     class PartitionStorage : IPartitionState
     {
+        readonly NetheriteOrchestrationServiceSettings settings;
         readonly string taskHubName;
         readonly string pathPrefix;
         readonly ILogger logger;
         readonly ILogger performanceLogger;
         readonly MemoryTracker memoryTracker;
-
-        readonly CloudStorageAccount storageAccount;
-        readonly string localFileDirectory;
-        readonly CloudStorageAccount pageBlobStorageAccount;
+        //readonly CloudStorageAccount storageAccount;
+        //readonly string localFileDirectory;
+        //readonly CloudStorageAccount pageBlobStorageAccount;
 
         Partition partition;
         BlobManager blobManager;
@@ -41,31 +41,14 @@ namespace DurableTask.Netherite.Faster
 
         public PartitionStorage(NetheriteOrchestrationServiceSettings settings, string pathPrefix, MemoryTracker memoryTracker, ILogger logger, ILogger performanceLogger)
         {
+            this.settings = settings;
             this.taskHubName = settings.HubName;
             this.pathPrefix = pathPrefix;
             this.logger = logger;
             this.performanceLogger = performanceLogger;
             this.memoryTracker = memoryTracker;
 
-            string connectionString = settings.ResolvedStorageConnectionString;
-            string pageBlobConnectionString = settings.ResolvedPageBlobStorageConnectionString;
-
-            if (!string.IsNullOrEmpty(settings.UseLocalDirectoryForPartitionStorage))
-            {
-                this.localFileDirectory = settings.UseLocalDirectoryForPartitionStorage;
-            }
-            else
-            { 
-                this.storageAccount = CloudStorageAccount.Parse(connectionString);
-            }
-            if (pageBlobConnectionString != connectionString && !string.IsNullOrEmpty(pageBlobConnectionString))
-            {
-                this.pageBlobStorageAccount = CloudStorageAccount.Parse(pageBlobConnectionString);
-            }
-            else
-            {
-                this.pageBlobStorageAccount = this.storageAccount;
-            }
+        
 
             if (settings.TestHooks?.CacheDebugger != null)
             {
@@ -98,9 +81,7 @@ namespace DurableTask.Netherite.Faster
             int psfCount = 0;
 
             this.blobManager = new BlobManager(
-                this.storageAccount,
-                this.pageBlobStorageAccount,
-                this.localFileDirectory,
+                this.settings,
                 this.taskHubName,
                 this.pathPrefix,
                 partition.Settings.TestHooks?.FaultInjector,

src/DurableTask.Netherite/StorageLayer/IStorageLayerFactory.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{ 
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+
+    interface IStorageLayerFactory
+    {
+        IStorageLayer Create(NetheriteOrchestrationService orchestrationService);
+    }
+}

src/DurableTask.Netherite/StorageLayer/Memory/MemoryStorageProvider.cs

@@ -48,7 +48,7 @@ namespace DurableTask.Netherite
                     TaskhubGuid = Guid.NewGuid(),
                     CreationTimestamp = DateTime.UtcNow,
                     StorageFormat = String.Empty,
-                    PartitionCount = 1,
+                    PartitionCount = this.settings.PartitionCount,
                 };
                 return true;
             }

src/DurableTask.Netherite/StorageLayer/StorageChoices.cs

@@ -0,0 +1,31 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+
+    /// <summary>
+    /// Configuration options for the storage layer
+    /// </summary>
+    public enum StorageChoices
+    {
+        /// <summary>
+        /// Does not store any state to durable storage, just keeps it in memory. 
+        /// Intended for testing scenarios.
+        /// </summary>
+        Memory = 0,
+
+        /// <summary>
+        /// Uses the Faster key-value store.
+        /// </summary>
+        Faster = 1,
+
+        /// <summary>
+        /// Uses a custom dependency-injected storage layer
+        /// </summary>
+        Custom = 2,
+    }
+}

src/DurableTask.Netherite/Tracing/OrchestrationServiceTraceHelper.cs

@@ -29,7 +29,7 @@ namespace DurableTask.Netherite
             this.serviceInstanceId = Guid.NewGuid();
         }
 
-        public void TraceCreated(int processorCount, TransportConnectionString.TransportChoices transport, TransportConnectionString.StorageChoices storage)
+        public void TraceCreated(int processorCount, TransportChoices transport, StorageChoices storage)
         {
             if (this.logLevelLimit <= LogLevel.Information)
             {

src/DurableTask.Netherite/TransportLayer/EventHubs/EventHubsConnections.cs

@@ -15,7 +15,7 @@ namespace DurableTask.Netherite.EventHubsTransport
 
     class EventHubsConnections
     {
-        readonly string connectionString;
+        readonly ConnectionInfo connectionInfo;
         readonly string[] clientHubs;
         readonly string partitionHub;
         readonly string loadMonitorHub;
@@ -29,7 +29,6 @@ namespace DurableTask.Netherite.EventHubsTransport
 
         public const int NumClientChannels = 2;
 
-        public string Endpoint { get; private set; }
         public DateTime CreationTimestamp { get; private set; }
 
         public ConcurrentDictionary<int, EventHubsSender<PartitionUpdateEvent>> _partitionSenders = new ConcurrentDictionary<int, EventHubsSender<PartitionUpdateEvent>>();
@@ -42,18 +41,18 @@ namespace DurableTask.Netherite.EventHubsTransport
         int GetClientBucket(Guid clientId, int index) => (int)((Fnv1aHashHelper.ComputeHash(clientId.ToByteArray()) + index) % (uint)this.clientPartitions.Count);
 
         public EventHubsConnections(
-            string connectionString, 
+            ConnectionInfo connectionInfo, 
             string partitionHub,
             string[] clientHubs,
             string loadMonitorHub)
         {
-            this.connectionString = connectionString;
+            this.connectionInfo = connectionInfo;
             this.partitionHub = partitionHub;
             this.clientHubs = clientHubs;
             this.loadMonitorHub = loadMonitorHub;
         }
 
-        public string Fingerprint => $"{this.Endpoint}{this.partitionHub}/{this.CreationTimestamp:o}";
+        public string Fingerprint => $"{this.connectionInfo.HostName}{this.partitionHub}/{this.CreationTimestamp:o}";
 
         public async Task StartAsync(TaskhubParameters parameters)
         {
@@ -94,30 +93,26 @@ namespace DurableTask.Netherite.EventHubsTransport
         async Task EnsureEventHubExistsAsync(string eventHubName, int partitionCount)
         {
             this.TraceHelper.LogDebug("Creating EventHub {name}", eventHubName);
-            bool success = await EventHubsUtil.EnsureEventHubExistsAsync(this.connectionString, eventHubName, partitionCount);
+            bool success = await EventHubsUtil.EnsureEventHubExistsAsync(this.connectionInfo, eventHubName, partitionCount, CancellationToken.None);
             if (success)
             {
-                this.TraceHelper.LogInformation("Created EventHub {name}", eventHubName);
+                this.TraceHelper.LogInformation("Created EventHub {name}", eventHubName, CancellationToken.None);
             }
             else
             {
-                this.TraceHelper.LogDebug("Conflict on EventHub {name}", eventHubName);
+                this.TraceHelper.LogDebug("Conflict on EventHub {name}", eventHubName, CancellationToken.None);
                 await Task.Delay(TimeSpan.FromSeconds(5));
             }
         }
 
         internal async Task DeletePartitions()
         {
-            await EventHubsUtil.DeleteEventHubIfExistsAsync(this.connectionString, this.partitionHub);
+            await EventHubsUtil.DeleteEventHubIfExistsAsync(this.connectionInfo, this.partitionHub, CancellationToken.None);
         }
 
         public async Task EnsurePartitionsAsync(int partitionCount, int retries = EventHubCreationRetries)
         {
-            var connectionStringBuilder = new EventHubsConnectionStringBuilder(this.connectionString)
-            {
-                EntityPath = this.partitionHub
-            };
-            var client = EventHubClient.CreateFromConnectionString(connectionStringBuilder.ToString());
+            var client = this.connectionInfo.CreateEventHubClient(this.partitionHub);
             try
             {
                 var runtimeInformation = await client.GetRuntimeInformationAsync();
@@ -126,7 +121,6 @@ namespace DurableTask.Netherite.EventHubsTransport
                 {
                     // we were successful. Record information and create a flat list of partition partitions
                     this.partitionClient = client;
-                    this.Endpoint = connectionStringBuilder.Endpoint.ToString();
                     this.CreationTimestamp = runtimeInformation.CreatedAt;
                     for (int i = 0; i < partitionCount; i++)
                     {
@@ -138,7 +132,7 @@ namespace DurableTask.Netherite.EventHubsTransport
                 {
                     // we have to create a fresh one
                     this.TraceHelper.LogWarning("Deleting existing partition EventHub because of partition count mismatch.");
-                    await EventHubsUtil.DeleteEventHubIfExistsAsync(this.connectionString, this.partitionHub);
+                    await EventHubsUtil.DeleteEventHubIfExistsAsync(this.connectionInfo, this.partitionHub, CancellationToken.None);
                     await Task.Delay(TimeSpan.FromSeconds(10));
                 }
             }
@@ -183,13 +177,9 @@ namespace DurableTask.Netherite.EventHubsTransport
 
         async Task<(EventHubClient, EventHubRuntimeInformation)> EnsureClientAsync(int i, int retries = EventHubCreationRetries)
         {
-            var connectionStringBuilder = new EventHubsConnectionStringBuilder(this.connectionString)
-            {
-                EntityPath = this.clientHubs[i]
-            };
             try
             {
-                var client = EventHubClient.CreateFromConnectionString(connectionStringBuilder.ToString());
+                var client = this.connectionInfo.CreateEventHubClient(this.clientHubs[i]);
                 var runtimeInformation = await client.GetRuntimeInformationAsync();
                 return (client, runtimeInformation);
             }
@@ -205,13 +195,9 @@ namespace DurableTask.Netherite.EventHubsTransport
         async Task EnsureLoadMonitorAsync(int retries = EventHubCreationRetries)
         {
             // create loadmonitor client
-            var connectionStringBuilder = new EventHubsConnectionStringBuilder(this.connectionString)
-            {
-                EntityPath = loadMonitorHub,
-            };
             try
             {
-                this.loadMonitorClient = EventHubClient.CreateFromConnectionString(connectionStringBuilder.ToString());
+                this.loadMonitorClient = this.connectionInfo.CreateEventHubClient(this.loadMonitorHub);
                 var runtimeInformation = await this.loadMonitorClient.GetRuntimeInformationAsync();
                 return;
             }
@@ -223,13 +209,9 @@ namespace DurableTask.Netherite.EventHubsTransport
             await this.EnsureLoadMonitorAsync(retries - 1);
         }
 
-        public static async Task<List<long>> GetQueuePositionsAsync(string connectionString, string partitionHub)
+        public static async Task<List<long>> GetQueuePositionsAsync(ConnectionInfo connectionInfo, string partitionHub)
         {
-            var connectionStringBuilder = new EventHubsConnectionStringBuilder(connectionString)
-            {
-                EntityPath = partitionHub,
-            };
-            var client = EventHubClient.CreateFromConnectionString(connectionStringBuilder.ToString());
+            var client = connectionInfo.CreateEventHubClient(partitionHub);
             try
             {
                 var runtimeInformation = await client.GetRuntimeInformationAsync();

src/DurableTask.Netherite/TransportLayer/EventHubs/EventHubsTransport.cs

@@ -28,7 +28,6 @@ namespace DurableTask.Netherite.EventHubsTransport
     {
         readonly TransportAbstraction.IHost host;
         readonly NetheriteOrchestrationServiceSettings settings;
-        readonly CloudStorageAccount cloudStorageAccount;
         readonly ILogger logger;
         readonly EventHubsTraceHelper traceHelper;
         readonly IStorageLayer storage;
@@ -59,16 +58,15 @@ namespace DurableTask.Netherite.EventHubsTransport
         {
             if (storage is MemoryStorageLayer)
             {
-                throw new InvalidOperationException($"Configuration error: in-memory storage cannot be used together with a real event hubs namespace");
+                throw new NetheriteConfigurationException($"Configuration error: in-memory storage cannot be used together with a real event hubs namespace");
             }
 
             this.host = host;
             this.settings = settings;
-            this.cloudStorageAccount = CloudStorageAccount.Parse(this.settings.ResolvedStorageConnectionString);
             this.storage = storage;
-            string namespaceName = TransportConnectionString.EventHubsNamespaceName(settings.ResolvedTransportConnectionString);
+            string namespaceName = settings.EventHubsConnection.ResourceName;
             this.logger = EventHubsTraceHelper.CreateLogger(loggerFactory);
-            this.traceHelper = new EventHubsTraceHelper(this.logger, settings.TransportLogLevelLimit, null, this.cloudStorageAccount.Credentials.AccountName, settings.HubName, namespaceName);
+            this.traceHelper = new EventHubsTraceHelper(this.logger, settings.TransportLogLevelLimit, null, settings.StorageAccountName, settings.HubName, namespaceName);
             this.ClientId = Guid.NewGuid();
         }
 
@@ -89,21 +87,22 @@ namespace DurableTask.Netherite.EventHubsTransport
             // check that we are the correct taskhub!
             if (this.parameters.TaskhubName != this.settings.HubName)
             {
-                throw new InvalidOperationException($"The specified taskhub name does not match the task hub name in storage");
+                throw new NetheriteConfigurationException($"The specified taskhub name does not match the task hub name in storage");
             }
 
             this.taskhubGuid = this.parameters.TaskhubGuid.ToByteArray();
             (string containerName, string path) = this.storage.GetTaskhubPathPrefix(this.parameters);
             this.pathPrefix = path;
 
-            var cloudBlobClient = this.cloudStorageAccount.CreateCloudBlobClient();
+            var cloudStorageAccount = await this.settings.BlobStorageConnection.GetAzureStorageV11AccountAsync();
+            var cloudBlobClient = cloudStorageAccount.CreateCloudBlobClient();
             this.cloudBlobContainer = cloudBlobClient.GetContainerReference(containerName);
             this.partitionScript = this.cloudBlobContainer.GetBlockBlobReference("partitionscript.json");
 
             // check that the storage format is supported
             BlobManager.CheckStorageFormat(this.parameters.StorageFormat, this.settings);
 
-            this.connections = new EventHubsConnections(this.settings.ResolvedTransportConnectionString, EventHubsTransport.PartitionHub, EventHubsTransport.ClientHubs, EventHubsTransport.LoadMonitorHub)
+            this.connections = new EventHubsConnections(this.settings.EventHubsConnection, EventHubsTransport.PartitionHub, EventHubsTransport.ClientHubs, EventHubsTransport.LoadMonitorHub)
             {
                 Host = host,
                 TraceHelper = this.traceHelper,
@@ -164,12 +163,11 @@ namespace DurableTask.Netherite.EventHubsTransport
 
                     string formattedCreationDate = this.connections.CreationTimestamp.ToString("o").Replace("/", "-");
 
-                    this.eventProcessorHost = new EventProcessorHost(
+                    this.eventProcessorHost = await this.settings.EventHubsConnection.GetEventProcessorHostAsync(
                         Guid.NewGuid().ToString(),
                         EventHubsTransport.PartitionHub,
                         EventHubsTransport.PartitionConsumerGroup,
-                        this.settings.ResolvedTransportConnectionString,
-                        this.settings.ResolvedStorageConnectionString,
+                        this.settings.BlobStorageConnection,
                         this.cloudBlobContainer.Name,
                         $"{this.pathPrefix}eh-checkpoints/{(EventHubsTransport.PartitionHub)}/{formattedCreationDate}");
 
@@ -191,8 +189,8 @@ namespace DurableTask.Netherite.EventHubsTransport
                     this.scriptedEventProcessorHost = new ScriptedEventProcessorHost(
                             EventHubsTransport.PartitionHub,
                             EventHubsTransport.PartitionConsumerGroup,
-                            this.settings.ResolvedTransportConnectionString,
-                            this.settings.ResolvedStorageConnectionString,
+                            this.settings.EventHubsConnection,
+                            this.settings.BlobStorageConnection,
                             this.cloudBlobContainer.Name,
                             this.host,
                             this,
@@ -211,12 +209,11 @@ namespace DurableTask.Netherite.EventHubsTransport
             {
                 this.traceHelper.LogInformation("Registering LoadMonitor Host with EventHubs");
 
-                this.loadMonitorHost = new EventProcessorHost(
+                this.loadMonitorHost = await this.settings.EventHubsConnection.GetEventProcessorHostAsync(
                         Guid.NewGuid().ToString(),
                         LoadMonitorHub,
                         LoadMonitorConsumerGroup,
-                        this.settings.ResolvedTransportConnectionString,
-                        this.settings.ResolvedStorageConnectionString,
+                        this.settings.BlobStorageConnection,
                         this.cloudBlobContainer.Name,
                         $"{this.pathPrefix}eh-checkpoints/{LoadMonitorHub}");
 
@@ -382,14 +379,36 @@ namespace DurableTask.Netherite.EventHubsTransport
             {
                 byte[] taskHubGuid = this.parameters.TaskhubGuid.ToByteArray();
                 TimeSpan longPollingInterval = TimeSpan.FromMinutes(1);
+                var backoffDelay = TimeSpan.Zero;
 
                 await this.clientConnectionsEstablished[index];
 
                 while (!this.shutdownSource.IsCancellationRequested)
                 {
-                    this.traceHelper.LogTrace("Client{clientId}.ch{index} waiting for new packets", Client.GetShortId(this.ClientId), index);
- 
-                    IEnumerable<EventData> eventData = await receiver.ReceiveAsync(1000, longPollingInterval);
+                    IEnumerable<EventData> eventData;
+
+                    try
+                    {
+                        this.traceHelper.LogTrace("Client{clientId}.ch{index} waiting for new packets", Client.GetShortId(this.ClientId), index);
+
+                        eventData = await receiver.ReceiveAsync(1000, longPollingInterval);
+
+                        backoffDelay = TimeSpan.Zero;
+                    }
+                    catch (Exception exception) when (!this.shutdownSource.IsCancellationRequested)
+                    {
+                        if (backoffDelay < TimeSpan.FromSeconds(30))
+                        {
+                            backoffDelay = backoffDelay + backoffDelay + TimeSpan.FromSeconds(2);
+                        }
+
+                        // if we lose access to storage temporarily, we back off, but don't quit
+                        this.traceHelper.LogError("Client{clientId}.ch{index} backing off for {backoffDelay} after error in receive loop: {exception}", Client.GetShortId(this.ClientId), index, backoffDelay, exception);
+
+                        await Task.Delay(backoffDelay);
+
+                        continue; // retry
+                    }
 
                     if (eventData != null)
                     {

src/DurableTask.Netherite/TransportLayer/EventHubs/ScriptedEventProcessorHost.cs

@@ -23,8 +23,8 @@ namespace DurableTask.Netherite.EventHubsTransport
     {
         readonly string eventHubPath;
         readonly string consumerGroupName;
-        readonly string eventHubConnectionString;
-        readonly string storageConnectionString;
+        readonly ConnectionInfo eventHubConnection;
+        readonly ConnectionInfo storageConnection;
         readonly string leaseContainerName;
         readonly string workerId;
         readonly TransportAbstraction.IHost host;
@@ -41,8 +41,8 @@ namespace DurableTask.Netherite.EventHubsTransport
         public ScriptedEventProcessorHost(
             string eventHubPath,
             string consumerGroupName,
-            string eventHubConnectionString,
-            string storageConnectionString,
+            ConnectionInfo eventHubConnection,
+            ConnectionInfo storageConnection,
             string leaseContainerName,
             TransportAbstraction.IHost host,
             TransportAbstraction.ISender sender,
@@ -54,8 +54,8 @@ namespace DurableTask.Netherite.EventHubsTransport
         {
             this.eventHubPath = eventHubPath;
             this.consumerGroupName = consumerGroupName;
-            this.eventHubConnectionString = eventHubConnectionString;
-            this.storageConnectionString = storageConnectionString;
+            this.eventHubConnection = eventHubConnection;
+            this.storageConnection = storageConnection;
             this.leaseContainerName = leaseContainerName;
             this.host = host;
             this.sender = sender;

src/DurableTask.Netherite/TransportLayer/ITransportLayerFactory.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{ 
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+
+    public interface ITransportLayerFactory
+    {
+        ITransportLayer Create(NetheriteOrchestrationService orchestrationService);
+    }
+}

src/DurableTask.Netherite/TransportLayer/SingleHost/SingleHostTransportProvider.cs

@@ -38,7 +38,6 @@ namespace DurableTask.Netherite.SingleHostTransport
             this.host = host;
             this.settings = settings;
             this.storage = storage;
-            TransportConnectionString.Parse(settings.ResolvedTransportConnectionString, out _, out _);
             this.numberPartitions = (uint) settings.PartitionCount;
             this.logger = logger;
             this.faultInjector = settings.TestHooks?.FaultInjector;

src/DurableTask.Netherite/TransportLayer/TransportChoices.cs

@@ -0,0 +1,33 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace DurableTask.Netherite
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Text;
+
+    /// <summary>
+    /// Configuration options for the transport layer
+    /// </summary>
+    public enum TransportChoices
+    {
+        /// <summary>
+        /// Passes messages through memory and puts all partitions on a single host
+        /// Intended primarily for testing scenarios, but can also provide a cheap and efficient option for
+        /// workloads whose CPU and memory load do not require more than one worker.
+        /// </summary>
+        SingleHost = 0,
+
+        /// <summary>
+        /// Passes messages through eventhubs; can distribute over multiple machines via
+        /// the eventhubs EventProcessor.
+        /// </summary>
+        EventHubs = 1,
+
+        /// <summary>
+        /// Uses a custom dependency-injected transport layer
+        /// </summary>
+        Custom = 2,
+    }
+}

test/DurableTask.Netherite.Tests/ConcurrentTestsFaster.cs

@@ -87,8 +87,8 @@ namespace DurableTask.Netherite.Tests
         public async Task EachScenarioOnce(bool restrictMemory)
         {
             var orchestrationTimeout = TimeSpan.FromMinutes(restrictMemory ? 10 : 5);
-            var startupTimeout = TimeSpan.FromMinutes(TransportConnectionString.IsPseudoConnectionString(this.settings.ResolvedTransportConnectionString) ? 1 : 3.5);
-            var shutDownTimeout = TimeSpan.FromMinutes(TransportConnectionString.IsPseudoConnectionString(this.settings.ResolvedTransportConnectionString) ? 0.1 : 3);
+            var startupTimeout = TimeSpan.FromMinutes(this.settings.UsesEmulation() ? 1 : 3.5);
+            var shutDownTimeout = TimeSpan.FromMinutes(this.settings.UsesEmulation() ? 0.1 : 3);
             var totalTimeout = startupTimeout + orchestrationTimeout + shutDownTimeout;
 
             using var _ = TestOrchestrationClient.WithExtraTime(TimeSpan.FromMinutes(restrictMemory ? 10 : 5));
@@ -141,9 +141,9 @@ namespace DurableTask.Netherite.Tests
         public async Task ScaleSmallScenarios(bool useReplayChecker, bool restrictMemory, int multiplicity)
         {
             var orchestrationTimeout = TimeSpan.FromMinutes((restrictMemory ? 10 : 5) + multiplicity * (restrictMemory ? 0.5 : 0.1));
-            var startupTimeout = TimeSpan.FromMinutes(TransportConnectionString.IsPseudoConnectionString(this.settings.ResolvedTransportConnectionString) ? 1 : 3.5);
+            var startupTimeout = TimeSpan.FromMinutes(this.settings.UsesEmulation() ? 1 : 3.5);
             var testTimeout = orchestrationTimeout + TimeSpan.FromMinutes(multiplicity * 0.2);
-            var shutDownTimeout = TimeSpan.FromMinutes(TransportConnectionString.IsPseudoConnectionString(this.settings.ResolvedTransportConnectionString) ? 0.1 : 3);
+            var shutDownTimeout = TimeSpan.FromMinutes(this.settings.UsesEmulation() ? 0.1 : 3);
             var totalTimeout = startupTimeout + testTimeout + shutDownTimeout;
 
             using var _ = TestOrchestrationClient.WithExtraTime(orchestrationTimeout);

test/DurableTask.Netherite.Tests/TestConstants.cs

@@ -17,11 +17,11 @@ namespace DurableTask.Netherite.Tests
         {
             if (string.IsNullOrEmpty(Environment.GetEnvironmentVariable(StorageConnectionName)))
             {
-                throw new InvalidOperationException($"To run tests, environment must define '{StorageConnectionName}'");
+                throw new NetheriteConfigurationException($"To run tests, environment must define '{StorageConnectionName}'");
             }
             if (requiresTransportSpec && string.IsNullOrEmpty(Environment.GetEnvironmentVariable(EventHubsConnectionName)))
             {
-                throw new InvalidOperationException($"To run tests, environment must define '{EventHubsConnectionName}'");
+                throw new NetheriteConfigurationException($"To run tests, environment must define '{EventHubsConnectionName}'");
             }
         }
 
@@ -53,7 +53,7 @@ namespace DurableTask.Netherite.Tests
             //settings.ResolvedStorageConnectionString = "";
             //settings.UseLocalDirectoryForPartitionStorage = $"{Environment.GetEnvironmentVariable("temp")}\\FasterTestStorage";
 
-            settings.Validate((name) => Environment.GetEnvironmentVariable(name));
+            settings.Validate(new ConnectionNameToConnectionStringResolver((name) => Environment.GetEnvironmentVariable(name)));
             settings.TestHooks = new TestHooks();
 
             return settings;
@@ -67,5 +67,9 @@ namespace DurableTask.Netherite.Tests
         internal static TestOrchestrationHost GetTestOrchestrationHost(ILoggerFactory loggerFactory)
             => new TestOrchestrationHost(GetNetheriteOrchestrationServiceSettings(), loggerFactory);
 
+        internal static bool UsesEmulation(this NetheriteOrchestrationServiceSettings settings)
+        {
+            return TransportConnectionString.IsPseudoConnectionString(settings.EventHubsConnectionName);
+        }
     }
 }

test/ScaleMonitor/Program.cs

@@ -27,7 +27,7 @@ namespace ScalingTests
                 ClientLogLevelLimit = LogLevel.Trace,
                 LoadMonitorLogLevelLimit = LogLevel.Trace,
             };
-            settings.Validate((string connectionName) => Environment.GetEnvironmentVariable(connectionName));
+            settings.Validate(ConnectionResolver.FromConnectionNameToConnectionStringResolver((string connectionName) => Environment.GetEnvironmentVariable(connectionName)));
             var loggerFactory = new LoggerFactory();
             loggerFactory.AddProvider(new ConsoleLoggerProvider());
             var logger = loggerFactory.CreateLogger("Main");