Bring back DomainNameRoleInstanceTelemetryInitializer as there is no other initializer or base sdk which can populate roleinstance and nodename for Linux. Fix 671

src/Microsoft.ApplicationInsights.AspNetCore/Extensions/ApplicationInsightsExtensions.cs

@@ -134,6 +134,7 @@ namespace Microsoft.Extensions.DependencyInjection
             {
                 services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
 
+                services.AddSingleton<ITelemetryInitializer, ApplicationInsights.AspNetCore.TelemetryInitializers.DomainNameRoleInstanceTelemetryInitializer>();
                 services.AddSingleton<ITelemetryInitializer, AzureWebAppRoleEnvironmentTelemetryInitializer>();                
                 services.AddSingleton<ITelemetryInitializer, ComponentVersionTelemetryInitializer>();
                 services.AddSingleton<ITelemetryInitializer, ClientIpHeaderTelemetryInitializer>();

src/Microsoft.ApplicationInsights.AspNetCore/TelemetryInitializers/DomainNameRoleInstanceTelemetryInitializer.cs

@@ -0,0 +1,65 @@
+namespace Microsoft.ApplicationInsights.AspNetCore.TelemetryInitializers
+{
+    using System;
+    using System.Globalization;
+    using System.Net;
+    using System.Net.NetworkInformation;
+    using System.Threading;
+    using Channel;
+    using Microsoft.ApplicationInsights.DataContracts;
+    using Microsoft.ApplicationInsights.Extensibility.Implementation;
+    using Microsoft.AspNetCore.Http;
+
+    /// <summary>
+    /// A telemetry initializer that populates cloud context role instance.
+    /// </summary>
+    public class DomainNameRoleInstanceTelemetryInitializer : TelemetryInitializerBase
+    {
+        private string roleInstanceName;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="DomainNameRoleInstanceTelemetryInitializer" /> class.
+        /// </summary>
+        /// <param name="httpContextAccessor">HTTP context accessor.</param>
+        public DomainNameRoleInstanceTelemetryInitializer(IHttpContextAccessor httpContextAccessor) : base(httpContextAccessor)
+        {
+        }
+
+        /// <summary>
+        /// Initializes role instance name and node name with the host name.
+        /// </summary>
+        /// <param name="platformContext">Platform context.</param>
+        /// <param name="requestTelemetry">Request telemetry.</param>
+        /// <param name="telemetry">Telemetry item.</param>
+        protected override void OnInitializeTelemetry(HttpContext platformContext, RequestTelemetry requestTelemetry, ITelemetry telemetry)
+        {
+            if (string.IsNullOrEmpty(telemetry.Context.Cloud.RoleInstance))
+            {
+                var name = LazyInitializer.EnsureInitialized(ref this.roleInstanceName, this.GetMachineName);
+                telemetry.Context.Cloud.RoleInstance = name;
+            }
+
+            InternalContext internalContext = telemetry.Context.GetInternalContext();
+            if (string.IsNullOrEmpty(internalContext.NodeName))
+            {
+                var name = LazyInitializer.EnsureInitialized(ref this.roleInstanceName, this.GetMachineName);
+                internalContext.NodeName = name;
+            }
+        }
+
+        private string GetMachineName()
+        {
+            string hostName = Dns.GetHostName();
+
+            // Issue #61: For dnxcore machine name does not have domain name like in full framework 
+#if !NETSTANDARD1_6
+            string domainName = IPGlobalProperties.GetIPGlobalProperties().DomainName;
+            if (!hostName.EndsWith(domainName, StringComparison.OrdinalIgnoreCase))
+            {
+                hostName = string.Format(CultureInfo.InvariantCulture, "{0}.{1}", hostName, domainName);
+            }
+#endif
+            return hostName;
+        }
+    }
+}

test/Microsoft.ApplicationInsights.AspNetCore.Tests/Extensions/ApplicationInsightsExtensionsTests.cs

@@ -52,6 +52,7 @@ namespace Microsoft.Extensions.DependencyInjection.Test
         public static class AddApplicationInsightsTelemetry
         {
             [Theory]
+            [InlineData(typeof(ITelemetryInitializer), typeof(ApplicationInsights.AspNetCore.TelemetryInitializers.DomainNameRoleInstanceTelemetryInitializer), ServiceLifetime.Singleton)]
             [InlineData(typeof(ITelemetryInitializer), typeof(AzureWebAppRoleEnvironmentTelemetryInitializer), ServiceLifetime.Singleton)]            
             [InlineData(typeof(ITelemetryInitializer), typeof(ComponentVersionTelemetryInitializer), ServiceLifetime.Singleton)]
             [InlineData(typeof(ITelemetryInitializer), typeof(ClientIpHeaderTelemetryInitializer), ServiceLifetime.Singleton)]
@@ -69,6 +70,7 @@ namespace Microsoft.Extensions.DependencyInjection.Test
             }
 
             [Theory]
+            [InlineData(typeof(ITelemetryInitializer), typeof(ApplicationInsights.AspNetCore.TelemetryInitializers.DomainNameRoleInstanceTelemetryInitializer), ServiceLifetime.Singleton)]
             [InlineData(typeof(ITelemetryInitializer), typeof(AzureWebAppRoleEnvironmentTelemetryInitializer), ServiceLifetime.Singleton)]            
             [InlineData(typeof(ITelemetryInitializer), typeof(ComponentVersionTelemetryInitializer), ServiceLifetime.Singleton)]
             [InlineData(typeof(ITelemetryInitializer), typeof(ClientIpHeaderTelemetryInitializer), ServiceLifetime.Singleton)]

test/Microsoft.ApplicationInsights.AspNetCore.Tests/TelemetryInitializers/DomainNameRoleInstanceTelemetryInitializerTests.cs

@@ -0,0 +1,84 @@
+namespace Microsoft.ApplicationInsights.AspNetCore.Tests.ContextInitializers
+{
+    using System;
+    using System.Globalization;
+    using System.Net;
+    using System.Net.NetworkInformation;
+    using Helpers;
+    using Microsoft.ApplicationInsights.AspNetCore.TelemetryInitializers;
+    using Microsoft.ApplicationInsights.DataContracts;
+    using Microsoft.ApplicationInsights.Extensibility.Implementation;
+    using Microsoft.AspNetCore.Http;
+    using Xunit;
+
+    public class DomainNameRoleInstanceTelemetryInitializerTests
+    {
+        private const string TestListenerName = "TestListener";
+
+        [Fact]
+        public void InitializeThrowIfHttpContextAccessorIsNull()
+        {
+            Assert.ThrowsAny<ArgumentNullException>(() =>
+            {
+                var initializer = new DomainNameRoleInstanceTelemetryInitializer(null);
+            });
+        }
+
+        [Fact]
+        public void InitializeDoesNotThrowIfHttpContextIsUnavailable()
+        {
+            var ac = new HttpContextAccessor() { HttpContext = null };
+
+            var initializer = new DomainNameRoleInstanceTelemetryInitializer(ac);
+
+            initializer.Initialize(new RequestTelemetry());
+        }
+
+        [Fact]
+        public void InitializeDoesNotThrowIfRequestTelemetryIsUnavailable()
+        {
+            var ac = new HttpContextAccessor() { HttpContext = new DefaultHttpContext() };
+
+            var initializer = new DomainNameRoleInstanceTelemetryInitializer(ac);
+
+            initializer.Initialize(new RequestTelemetry());
+        }
+
+        [Fact]
+        public void RoleInstanceNameIsSetToDomainAndHost()
+        {
+            var contextAccessor = HttpContextAccessorHelper.CreateHttpContextAccessor(new RequestTelemetry(), null);
+            var source = new DomainNameRoleInstanceTelemetryInitializer(contextAccessor);
+            var requestTelemetry = new RequestTelemetry();
+            source.Initialize(requestTelemetry);
+
+            string hostName = Dns.GetHostName();
+
+#if NET451 || NET46
+            string domainName = IPGlobalProperties.GetIPGlobalProperties().DomainName;
+            if (hostName.EndsWith(domainName, StringComparison.OrdinalIgnoreCase) == false)
+            {
+                hostName = string.Format(CultureInfo.InvariantCulture, "{0}.{1}", hostName, domainName);
+            }
+#endif
+
+            Assert.Equal(hostName, requestTelemetry.Context.Cloud.RoleInstance);
+            Assert.Equal(hostName, requestTelemetry.Context.GetInternalContext().NodeName);
+        }
+
+        [Fact]
+        public void ContextInitializerDoesNotOverrideMachineName()
+        {
+            var contextAccessor = HttpContextAccessorHelper.CreateHttpContextAccessor(new RequestTelemetry(), null);
+            var source = new DomainNameRoleInstanceTelemetryInitializer(contextAccessor);
+            var requestTelemetry = new RequestTelemetry();
+            requestTelemetry.Context.Cloud.RoleInstance = "Test";
+            requestTelemetry.Context.GetInternalContext().NodeName = "Test1";
+
+            source.Initialize(requestTelemetry);
+
+            Assert.Equal("Test", requestTelemetry.Context.Cloud.RoleInstance);
+            Assert.Equal("Test1", requestTelemetry.Context.GetInternalContext().NodeName);
+        }
+    }
+}