Azure WebJobs SDK Extensions

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This repo contains binding extensions for the Azure WebJobs SDK. See the Azure WebJobs SDK repo for more information. The binding extensions in this repo are available as the Microsoft.Azure.WebJobs.Extensions nuget package. Note: some of the extensions in this repo (like SendGrid, etc.) live in their own separate nuget packages following a standard naming scheme (e.g. Microsoft.Azure.WebJobs.Extensions.SendGrid). Also note that some of the features discussed here or in the wiki may still be in pre-release. To access those features you may need to pull the very latest pre-release packages from our "nightlies" package feed (instructions here).

The wiki contains information on how to author your own binding extensions. See the Binding Extensions Overview for more details. A sample project is also provided that demonstrates the bindings in action.

Extensions all follow the same "add" pattern for registration - after referencing the package the extension lives in, you call the corresponding "add" method to register the extension. These "add" methods are extension methods that often take optional configuration objects to customize the behavior of the extension. For example, the b.AddAzureStorage() call below registers the Azure Storage extension.

var builder = new HostBuilder();
builder.ConfigureWebJobs(b =>
{
    b.AddAzureStorageCoreServices();
    b.AddAzureStorage();
});
builder.ConfigureLogging((context, b) =>
{
    b.AddConsole();
});

var host = builder.Build();
using (host)
{
    await host.RunAsync();
}

Other Extension Repositories

Not all extensions for webjobs live here. Over time we expect them to move towards having their own ship cycle and repository. You can find other Azure owned extensions using this github query. Right now there are:

• https://github.com/Azure/azure-functions-durable-extension
• https://github.com/Azure/azure-functions-eventgrid-extension
• https://github.com/Azure/azure-functions-iothub-extension

Extensions

The extensions included in this repo include the following. This is not an exhaustive list - see the ExtensionsSample project in this repo for more information extension samples.

TimerTrigger

A fully featured Timer trigger for scheduled jobs that supports cron expressions, as well as other schedule expressions. A couple of examples:

// Runs once every 5 minutes
public static void CronJob([TimerTrigger("0 */5 * * * *")] TimerInfo timer)
{
    Console.WriteLine("Cron job fired!");
}

// Runs immediately on startup, then every two hours thereafter
public static void StartupJob(
    [TimerTrigger("0 0 */2 * * *", RunOnStartup = true)] TimerInfo timerInfo)
{
    Console.WriteLine("Timer job fired!");
}

// Runs once every 30 seconds
public static void TimerJob([TimerTrigger("00:00:30")] TimerInfo timer)
{
    Console.WriteLine("Timer job fired!");
}

// Runs on a custom schedule. You implement Type MySchedule which is called on to
// return the next occurrence time as needed
public static void CustomJob([TimerTrigger(typeof(MySchedule))] TimerInfo timer)
{
    Console.WriteLine("Custom job fired!");
}

The TimerTrigger also handles multi-instance scale out automatically - only a single instance of a particular timer function will be running across all instances (you don't want multiple instances to process the same timer event).

The first example above uses a cron expression to declare the schedule. Using these 6 fields {second} {minute} {hour} {day} {month} {day of the week} you can express arbitrarily complex schedules very concisely. Note: the 6 field format including seconds is less common, so in the various cron expression docs you find online you'll have to adjust for the extra field.

To register the Timer extensions, call config.UseTimers() in your startup code. For more information, see the TimerTrigger wiki page, and also the Timer samples.

FileTrigger / File

A trigger that monitors for file additions/changes to a particular directory, and triggers a job function when they occur. Here's an example that monitors for any *.dat files added to a particular directory, uploads them to blob storage, and deletes the files automatically after successful processing. The FileTrigger also handles multi-instance scale out automatically - only a single instance will process a particular file event. Also included is a non-trigger File binding allowing you to bind to input/output files.

public static void ImportFile(
    [FileTrigger(@"import\{name}", "*.dat", autoDelete: true)] Stream file,
    [Blob(@"processed/{name}")] CloudBlockBlob output,
    string name)
{
    output.UploadFromStream(file);
    file.Close();

    log.WriteLine(string.Format("Processed input file '{0}'!", name));
}

To register the File extensions, call config.UseFiles() in your startup code. For more information, see the File samples.

SendGrid

A SendGrid binding that allows you to easily send emails after your job functions complete. This extension lives in the Microsoft.Azure.WebJobs.Extensions.SendGrid package. Simply add your SendGrid ApiKey as an app setting or environment variable (use setting name AzureWebJobsSendGridApiKey), and you can write functions like the below which demonstrates full route binding for message fields. In this scenario, an email is sent each time a new order is successfully placed. The message fields are automatically bound to the CustomerEmail/CustomerName/OrderId properties of the Order object that triggered the function.

public static void ProcessOrder(
    [QueueTrigger(@"samples-orders")] Order order,
    [SendGrid(
        To = "{CustomerEmail}",
        Subject = "Thanks for your order (#{OrderId})!",
        Text = "{CustomerName}, we've received your order ({OrderId})!")]
    out Mail message)
{
    // You can set additional message properties here
}

Here's another example showing how you can easily send yourself notification mails to your own admin address when your jobs complete. In this case, the default To/From addresses come from the global SendGridConfiguration object specified on startup, so don't need to be specified.

public static void Purge(
    [QueueTrigger(@"purge-tasks")] PurgeTask task,
    [SendGrid(Subject = "Purge {Description} succeeded. Purged {Count} items")]
    out Mail message)
{
    // Purge logic here
}

The above messages are fully declarative, but you can also set the message properties in your job function code (e.g. add message attachments, etc.).

To register the SendGrid extensions, call config.UseSendGrid() in your startup code. For more information on the SendGrid binding, see the SendGrid samples.

Core Extensions

There are a set of triggers/bindings that can be registered by calling config.UseCore(). The Core extensions contain a set of general purpose bindings. For example, there is a binding for ExecutionContext which allows you to access invocation specific system information in your function. Here's an example showing how to access the function Invocation ID for the function:

public static void ProcessOrder(
    [QueueTrigger("orders")] Order order,
    TextWriter log,
    ExecutionContext context)
{
    log.WriteLine("InvocationId: {0}", context.InvocationId);
}

The invocation ID is used in the Dashboard logs, so having access to this programatically allows you to correlate an invocation to those logs. This might be useful if you're also logging to your own external system. To register the Core extensions, call config.Core() in your startup code.

DocumentDB

Use an Azure DocumentDB binding to easily create, read, and update JSON documents from a WebJob. This extension lives in Microsoft.Azure.WebJobs.Extensions.DocumentDB nuget package. To configure the binding, add the DocumentDB connection string as an app setting or environment variable using the setting name AzureWebJobsDocumentDBConnectionString.

By default, the collection and database must exist before the binding runs or it will throw an Exception. You can configure the binding to automatically create your datatabase and collection by setting CreateIfNotExists to true. This property only applies to out parameters. For input (lookup) scenarios, if the database or collection do not exist, the parameter is returned as null. To define a partition key for automatically-created collections, set the PartitionKey property. To control the throughput of the collection, set the CollectionThroughput property. For more information on partition keys and throughput, see Partitioning and scaling in Azure DocumentDB.

In this example, the newItem object is upserted into the ItemCollection collection of the ItemDb DocumentDB database. The collection will be automatically created if it does not exist, with a partition key of /mypartition and a throughput of 12000.

public static void InsertDocument(
    [QueueTrigger("sample")] QueueData trigger,
    [DocumentDB("ItemDb", "ItemCollection", CreateIfNotExists = true, PartitionKey = "/mypartition", CollectionThroughput = 12000)] out ItemDoc newItem)
{
    newItem = new ItemDoc()
    {
        Text = "sample text"
    };
}

The following sample performs a lookup based on the data in the queue trigger. The DocumentId and PartitionKey properties value of the QueueData object are used to query the ItemCollection document collection. The PartitionKey property is optional and does not need to be specified unless your collection has a partition key. If the document exists, it is provided in the item parameter. If not, the item parameter will be null. Inside the method, the item object is changed. This change is automatically sent back to the document collection when the method exits.

public static void ReadDocument(
    [QueueTrigger("sample")] QueueData trigger,
    [DocumentDB("ItemDb", "ItemCollection", Id = "{DocumentId}", PartitionKey = "{PartitionKey}")] JObject item)
{
    item["text"] = "Text changed!";
}

Sql Query Support

If you need to make a query to return many Documents from Document DB, use the SqlQuery property on the DocumentDBAttribute. This property supports runtime binding, so the example below will replace {QueueTrigger} with the value from the queue message. In order to prevent injection attacks, any binding string used in the SqlQuery property is replaced with a SqlParameter before being sent to your Document DB database. Queries must be of type JArray or IEnumerable<T>, where T is a type supported by Document DB (such as Document, JObject, or your own custom type). If you want to return all documents in a collection, you can remove the SqlQuery property and use JArray or IEnumerable<T> as your parameter type.

public static void ReadDocument(
    [QueueTrigger("sample")] string trigger,
    [DocumentDB("ItemDb", "ItemCollection", SqlQuery = "SELECT c.id, c.fullName, c.department FROM c where c.department = {QueueTrigger}")] IEnumerable<JObject> documents)
{
    foreach(JObject doc in documents)
    {
        // do something
    }
}

If you need more control, you can also specify a parameter of type DocumentClient. The following example uses DocumentClient to query for all documents in ItemCollection and log their ids.

public static void DocumentClient(
    [QueueTrigger("sample")] QueueData trigger,
    [DocumentDB] DocumentClient client,
    TraceWriter log)
{
    var collectionUri = UriFactory.CreateDocumentCollectionUri("ItemDb", "ItemCollection");
    var documents = client.CreateDocumentQuery(collectionUri);

    foreach (Document d in documents)
    {
        log.Info(d.Id);
    }
}

Azure Notification Hubs

An Azure Notification Hub binding allows you to easily send push notifications to any platform. This extension lives in Microsoft.Azure.WebJobs.Extensions.NotificationHubs nuget package. To configure the binding, add the NotificationHubs namespace connection string as an app setting or environment variable using the setting name AzureWebJobsNotificationHubsConnectionString and add the name of the NotificationHub as an app setting or environment variable using the setting name AzureWebJobsNotificationHubName.

Azure Notification Hub must be configured for the Platform Notifications Services (PNS) you want to use. For more information on configuring an Azure Notification Hub and developing a client applications that register for notifications, see [Getting started with Notification Hubs] (https://azure.microsoft.com/en-us/documentation/articles/notification-hubs-windows-store-dotnet-get-started/) and click your target client platform at the top.

The following sample sends windows toast notification when a new file is uploaded to a blob

 public static void SendNotification(
    [BlobTrigger("sample/{name}.{ext}")] Stream input, string name, string ext
    [NotificationHub] out Notification notification)
{
    string message = string.Format("File {0}.{1} uploaded to Blob container sample", name, ext);
    string toastPayload = string.Format("<toast><visual><binding template=\"ToastText01\"><text id=\"1\">{0}</text></binding></visual></toast>", message);
    notification = new WindowsNotification(toastPayload);
}

Here's an example for sending [template notification] (https://msdn.microsoft.com/en-us/library/azure/dn530748.aspx) to an userId [tag] (https://azure.microsoft.com/en-us/documentation/articles/notification-hubs-routing-tag-expressions/) in the queue trigger. The userId is a property value of the QueueData object.

public static void SendTemplateNotification(
    [QueueTrigger("queue")] QueueData queueData,
    [NotificationHub(TagExpression = "{userId}")] out string messageProperties)
{
    messageProperties = "{\"message\":\"Hello\",\"location\":\"Redmond\"}";
}

Twilio SMS

A Twilio binding that allows you to easily send SMS messages from your job functions. This extension lives in the Microsoft.Azure.WebJobs.Extensions.Twilio package. Simply add your Twilio Account SID and Auth Token as app settings or environment variables (with settings named AzureWebJobsTwilioAccountSid and AzureWebJobsTwilioAuthToken, respectively), and you can write functions like the below which demonstrates full route binding for message fields. In this scenario, an SMS message is sent each time a new order is successfully placed. The message fields are automatically bound to the CustomerPhoneNumber/StorePhoneNumber/CustomerName/OrderId properties of the Order object that triggered the function.

 public static void ProcessOrder(
    [QueueTrigger(@"samples-orders")] Order order,
    [TwilioSms(
        To = "{CustomerPhoneNumber}",
        From = "{StorePhoneNumber}",
        Body = "{CustomerName}, we've received your order ({OrderId}) and have begun processing it!")]
    out SMSMessage message)
{
    // You can set additional message properties here
    message = new SMSMessage();
}

Here's another example showing how you can easily send yourself notification mails to your own admin address when your jobs complete. In this case, the default To/From addresses come from the global TwilioSmsConfiguration object specified on startup, so don't need to be specified.

public static void Purge(
    [QueueTrigger(@"purge-tasks")] PurgeTask task,
    [TwilioSms(Body = "Purge {Description} succeeded. Purged {Count} items")]
    out SMSMessage message)
{
    // Purge logic here
}

The above messages are fully declarative, but you can also set the message properties in your job function code (e.g. From number, To number, Body, etc.).

To register the Twilio SMS extensions, call config.UseTwilioSms() in your startup code. For more information on the Twilio binding, see the Twilio samples.

License

This project is under the benevolent umbrella of the .NET Foundation and is licensed under the MIT License

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.