[AppInsights] changing RoleName calculation to work with Functions slots

src/Microsoft.Azure.WebJobs.Logging.ApplicationInsights/DefaultTelemetryClientFactory.cs

@@ -9,7 +9,6 @@
 using Microsoft.ApplicationInsights.Extensibility.Implementation;
 using Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector;
 using Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.QuickPulse;
-using Microsoft.ApplicationInsights.WindowsServer;
 using Microsoft.ApplicationInsights.WindowsServer.Channel.Implementation;
 using Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel;
 using Microsoft.Extensions.Logging;
@@ -142,7 +141,7 @@ protected virtual QuickPulseTelemetryModule CreateQuickPulseTelemetryModule()
         internal static void AddInitializers(TelemetryConfiguration config)
         {
             // This picks up the RoleName from the server
-            config.TelemetryInitializers.Add(new AzureWebAppRoleEnvironmentTelemetryInitializer());
+            config.TelemetryInitializers.Add(new WebJobsRoleEnvironmentTelemetryInitializer());
 
             // This applies our special scope properties and gets RoleInstance name
             config.TelemetryInitializers.Add(new WebJobsTelemetryInitializer());

src/Microsoft.Azure.WebJobs.Logging.ApplicationInsights/WebJobs.Logging.ApplicationInsights.csproj

@@ -147,6 +147,7 @@
     <Compile Include="GlobalSuppressions.cs" />
     <Compile Include="ITelemetryClientFactory.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="WebJobsRoleEnvironmentTelmetryInitializer.cs" />
     <Compile Include="WebJobsTelemetryInitializer.cs" />
   </ItemGroup>
   <ItemGroup>

src/Microsoft.Azure.WebJobs.Logging.ApplicationInsights/WebJobsRoleEnvironmentTelmetryInitializer.cs

@@ -0,0 +1,82 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.ApplicationInsights.Channel;
+using Microsoft.ApplicationInsights.Extensibility;
+using Microsoft.ApplicationInsights.Extensibility.Implementation;
+
+namespace Microsoft.Azure.WebJobs.Logging.ApplicationInsights
+{
+    // This class was taken largely from https://raw.githubusercontent.com/Microsoft/ApplicationInsights-dotnet-server/91016d62f3181e10d4cf589ef8fd64dadb6b54a2/Src/WindowsServer/WindowsServer.Shared/AzureWebAppRoleEnvironmentTelemetryInitializer.cs, 
+    // but refactored so that it did not use WEBSITE_HOSTNAME, which is determined to be unreliable for functions during slot swaps.
+
+    /// <summary>
+    /// A telemetry initializer that will gather Azure Web App Role Environment context information.
+    /// </summary>    
+    internal class WebJobsRoleEnvironmentTelemetryInitializer : ITelemetryInitializer
+    {
+        internal const string AzureWebsiteName = "WEBSITE_SITE_NAME";
+        internal const string AzureWebsiteSlotName = "WEBSITE_SLOT_NAME";
+        private const string DefaultProductionSlotName = "production";
+        private const string WebAppSuffix = ".azurewebsites.net";
+
+        /// <summary>
+        /// Initializes <see cref="ITelemetry" /> device context.
+        /// </summary>
+        /// <param name="telemetry">The telemetry to initialize.</param>
+        public void Initialize(ITelemetry telemetry)
+        {
+            if (telemetry == null)
+            {
+                return;
+            }
+
+            // We cannot cache these values as the environment variables can change on the fly.
+            if (string.IsNullOrEmpty(telemetry.Context.Cloud.RoleName))
+            {
+                telemetry.Context.Cloud.RoleName = GetRoleName();
+            }
+
+            if (string.IsNullOrEmpty(telemetry.Context.GetInternalContext().NodeName))
+            {
+                telemetry.Context.GetInternalContext().NodeName = GetNodeName();
+            }
+        }
+
+        private static string GetRoleName()
+        {
+            return GetAzureWebsiteUniqueSlotName();
+        }
+
+        private static string GetNodeName()
+        {
+            string name = GetAzureWebsiteUniqueSlotName();
+
+            if (!string.IsNullOrEmpty(name))
+            {
+                // maintain previous behavior of node having the full url
+                name = name + WebAppSuffix;
+            }
+
+            return name;
+        }
+
+        /// <summary>
+        /// Gets a value that uniquely identifies the site and slot.
+        /// </summary>
+        private static string GetAzureWebsiteUniqueSlotName()
+        {
+            string name = Environment.GetEnvironmentVariable(AzureWebsiteName);
+            string slotName = Environment.GetEnvironmentVariable(AzureWebsiteSlotName);
+
+            if (!string.IsNullOrEmpty(slotName) &&
+                !string.Equals(slotName, DefaultProductionSlotName, StringComparison.OrdinalIgnoreCase))
+            {
+                name += $"-{slotName}";
+            }
+
+            return name?.ToLowerInvariant();
+        }
+    }
+}

test/Microsoft.Azure.WebJobs.Host.UnitTests/Loggers/DefaultTelemetryClientFactoryTests.cs

@@ -2,7 +2,6 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System.Linq;
-using Microsoft.ApplicationInsights.WindowsServer;
 using Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel;
 using Microsoft.Azure.WebJobs.Logging.ApplicationInsights;
 using Xunit;
@@ -20,7 +19,7 @@ public void InitializeConfiguguration_Configures()
             // Verify Initializers
             Assert.Equal(2, config.TelemetryInitializers.Count);
             // These will throw if there are not exactly one
-            config.TelemetryInitializers.OfType<AzureWebAppRoleEnvironmentTelemetryInitializer>().Single();
+            config.TelemetryInitializers.OfType<WebJobsRoleEnvironmentTelemetryInitializer>().Single();
             config.TelemetryInitializers.OfType<WebJobsTelemetryInitializer>().Single();
 
             // Verify Channel

test/Microsoft.Azure.WebJobs.Host.UnitTests/Loggers/WebJobsRoleEnvironmentTelemetryInitializerTests.cs

@@ -0,0 +1,71 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.ApplicationInsights.DataContracts;
+using Microsoft.ApplicationInsights.Extensibility.Implementation;
+using Microsoft.Azure.WebJobs.Logging.ApplicationInsights;
+using Xunit;
+
+namespace Microsoft.Azure.WebJobs.Host.UnitTests.Loggers
+{
+    public class WebJobsRoleEnvironmentTelemetryInitializerTests : IDisposable
+    {
+        public WebJobsRoleEnvironmentTelemetryInitializerTests()
+        {
+            // make sure these are clear before each test
+            SetEnvironmentVariables(null, null);
+        }
+
+        [Fact]
+        public void Initialize_DoesNotThrow_WhenNoEnvironmentVariables()
+        {
+            var initializer = new WebJobsRoleEnvironmentTelemetryInitializer();
+
+            var telemetry = new TraceTelemetry();
+            initializer.Initialize(telemetry);
+
+            Assert.Null(telemetry.Context.Cloud.RoleName);
+            Assert.Null(telemetry.Context.GetInternalContext().NodeName);
+        }
+
+        [Fact]
+        public void Initialize_WithSlot()
+        {
+            SetEnvironmentVariables("mytestsite", "Staging");
+
+            var initializer = new WebJobsRoleEnvironmentTelemetryInitializer();
+
+            var telemetry = new TraceTelemetry();
+            initializer.Initialize(telemetry);
+
+            Assert.Equal("mytestsite-staging", telemetry.Context.Cloud.RoleName);
+            Assert.Equal("mytestsite-staging.azurewebsites.net", telemetry.Context.GetInternalContext().NodeName);
+        }
+
+        [Fact]
+        public void Initialize_WithProductionSlot()
+        {
+            SetEnvironmentVariables("mytestsite", "Production");
+
+            var initializer = new WebJobsRoleEnvironmentTelemetryInitializer();
+
+            var telemetry = new TraceTelemetry();
+            initializer.Initialize(telemetry);
+
+            Assert.Equal("mytestsite", telemetry.Context.Cloud.RoleName);
+            Assert.Equal("mytestsite.azurewebsites.net", telemetry.Context.GetInternalContext().NodeName);
+        }
+
+        private static void SetEnvironmentVariables(string websiteName, string slotName)
+        {
+            Environment.SetEnvironmentVariable(WebJobsRoleEnvironmentTelemetryInitializer.AzureWebsiteName, websiteName);
+            Environment.SetEnvironmentVariable(WebJobsRoleEnvironmentTelemetryInitializer.AzureWebsiteSlotName, slotName);
+        }
+
+        public void Dispose()
+        {
+            SetEnvironmentVariables(null, null);
+        }
+    }
+}

test/Microsoft.Azure.WebJobs.Host.UnitTests/WebJobs.Host.UnitTests.csproj

@@ -316,6 +316,7 @@
     <Compile Include="Loggers\LoggerExtensionsTests.cs" />
     <Compile Include="Loggers\TestTelemetryChannel.cs" />
     <Compile Include="Loggers\TraceWriterFunctionInstanceLoggerTests.cs" />
+    <Compile Include="Loggers\WebJobsRoleEnvironmentTelemetryInitializerTests.cs" />
     <Compile Include="NullExtensionTypeLocator.cs" />
     <Compile Include="Protocols\FunctionStartedMessageExtensionsTests.cs" />
     <Compile Include="Protocols\ProtocolSerializationTests.cs" />