Azure · TimothyMothra · Oct 3, 2023 · Aug 31, 2023 · Sep 5, 2023 · Sep 11, 2023
@@ -1,12 +1,13 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <Description>An OpenTelemetry .NET exporter that exports to Azure Monitor</Description>
     <AssemblyTitle>AzureMonitor OpenTelemetry Exporter</AssemblyTitle>
     <Version>1.1.0-beta.1</Version>
     <!--The ApiCompatVersion is managed automatically and should not generally be modified manually.-->
-    <ApiCompatVersion>1.0.0</ApiCompatVersion>
+    <ApiCompatVersion Condition="'$(TargetFramework)' == 'netstandard2.0'">1.0.0</ApiCompatVersion>
     <PackageTags>Azure Monitor OpenTelemetry Exporter ApplicationInsights</PackageTags>
-    <TargetFrameworks>$(RequiredTargetFrameworks)</TargetFrameworks>
+    <!--NET6 is added here for trimming compatibility. This includes necessary annotations and System.Text.Json's "Source Generation" feature.-->
+    <TargetFrameworks>net6.0;$(RequiredTargetFrameworks)</TargetFrameworks>
     <IncludeOperationsSharedSource>true</IncludeOperationsSharedSource>
   </PropertyGroup>
 

@@ -14,10 +14,13 @@ public StackFrame(System.Diagnostics.StackFrame stackFrame, int frameId)
         {
             string fullName, assemblyName;
 
-            var methodInfo = stackFrame.GetMethod();
+            var methodInfo = stackFrame.GetMethodWithoutWarning();
             if (methodInfo == null)
             {
-                fullName = "unknown";
+                // In an AOT scenario GetMethod() will return null. Note this can happen even in non AOT scenarios.
+                // Instead, call ToString() which gives a string like this:
+                // "MethodName + 0x00 at offset 000 in file:line:column <filename unknown>:0:0"
+                fullName = stackFrame.ToString();
                 assemblyName = "unknown";
             }
             else

@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Tracing;
 using System.Runtime.CompilerServices;
 using Azure.Monitor.OpenTelemetry.Exporter.Internals.ConnectionString;
@@ -87,7 +88,7 @@ public void TransmissionFailed(int statusCode, TelemetryItemOrigin origin, bool
                         isAadEnabled: isAadEnabled,
                         instrumentationKey: connectionVars.InstrumentationKey,
                         configuredEndpoint: connectionVars.IngestionEndpoint,
-                        actualEndpoint: requestEndpoint);
+                        actualEndpoint: requestEndpoint ?? "null");
                 }
                 else
                 {
@@ -101,7 +102,7 @@ public void TransmissionFailed(int statusCode, TelemetryItemOrigin origin, bool
                             isAadEnabled: isAadEnabled,
                             instrumentationKey: connectionVars.InstrumentationKey,
                             configuredEndpoint: connectionVars.IngestionEndpoint,
-                            actualEndpoint: requestEndpoint);
+                            actualEndpoint: requestEndpoint ?? "null");
                     }
                 }
             }
@@ -115,12 +116,13 @@ public void TransmissionFailed(int statusCode, TelemetryItemOrigin origin, bool
                     isAadEnabled: isAadEnabled,
                     instrumentationKey: connectionVars.InstrumentationKey,
                     configuredEndpoint: connectionVars.IngestionEndpoint,
-                    actualEndpoint: requestEndpoint);
+                    actualEndpoint: requestEndpoint ?? "null");
             }
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Parameters to this method are primitive and are trimmer safe.")]
         [Event(8, Message = "Transmission failed. StatusCode: {0}. Error from Ingestion: {1}. Action: {2}. Origin: {3}. AAD Enabled: {4}. Instrumentation Key: {5}. Configured Endpoint: {6}. Actual Endpoint: {7}", Level = EventLevel.Critical)]
-        public void TransmissionFailed(int statusCode, string errorMessage, string action, string origin, bool isAadEnabled, string instrumentationKey, string configuredEndpoint, string? actualEndpoint)
+        public void TransmissionFailed(int statusCode, string errorMessage, string action, string origin, bool isAadEnabled, string instrumentationKey, string configuredEndpoint, string actualEndpoint)
             => WriteEvent(8, statusCode, errorMessage, action, origin, isAadEnabled, instrumentationKey, configuredEndpoint, actualEndpoint);
 
         [Event(9, Message = "{0} has been disposed.", Level = EventLevel.Informational)]
@@ -213,6 +215,7 @@ public void FailedToExtractActivityEvent(string activitySourceName, string activ
         [Event(17, Message = "Failed to extract Activity Event due to an exception. This telemetry item will be lost. ActivitySource: {0}. Activity: {1}. {2}", Level = EventLevel.Error)]
         public void FailedToExtractActivityEvent(string activitySourceName, string activityDisplayName, string exceptionMessage) => WriteEvent(17, activitySourceName, activityDisplayName, exceptionMessage);
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Parameters to this method are primitive and are trimmer safe.")]
         [Event(18, Message = "Maximum count of {0} Activity Links reached. Excess Links are dropped. ActivitySource: {1}. Activity: {2}.", Level = EventLevel.Warning)]
         public void ActivityLinksIgnored(int maxLinksAllowed, string activitySourceName, string activityDisplayName) => WriteEvent(18, maxLinksAllowed, activitySourceName, activityDisplayName);
 
@@ -279,9 +282,11 @@ public void FailedToTransmitFromStorage(bool isAadEnabled, string instrumentatio
             }
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Parameters to this method are primitive and are trimmer safe.")]
         [Event(25, Message = "Failed to transmit from storage due to an exception. AAD Enabled: {0}. Instrumentation Key: {1}. {2}", Level = EventLevel.Error)]
         public void FailedToTransmitFromStorage(bool isAadEnabled, string instrumentationKey, string exceptionMessage) => WriteEvent(25, isAadEnabled, instrumentationKey, exceptionMessage);
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Parameters to this method are primitive and are trimmer safe.")]
         [Event(26, Message = "Successfully transmitted a blob from storage. AAD Enabled: {0}. Instrumentation Key: {1}", Level = EventLevel.Verbose)]
         public void TransmitFromStorageSuccess(bool isAadEnabled, string instrumentationKey) => WriteEvent(26, isAadEnabled, instrumentationKey);
 
@@ -327,6 +332,7 @@ public void TransmissionSuccess(TelemetryItemOrigin origin, bool isAadEnabled, s
             }
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Parameters to this method are primitive and are trimmer safe.")]
         [Event(32, Message = "Successfully transmitted a batch of telemetry Items. Origin: {0}. AAD: {1}. Instrumentation Key: {2}", Level = EventLevel.Verbose)]
         public void TransmissionSuccess(string origin, bool isAadEnabled, string instrumentationKey) => WriteEvent(32, origin, isAadEnabled, instrumentationKey);
 
@@ -339,9 +345,11 @@ public void TransmitterFailed(TelemetryItemOrigin origin, bool isAadEnabled, str
             }
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Parameters to this method are primitive and are trimmer safe.")]
         [Event(33, Message = "Transmitter failed due to an exception. Origin: {0}. AAD: {1}. Instrumentation Key: {2}. {3}", Level = EventLevel.Error)]
         public void TransmitterFailed(string origin, bool isAadEnabled, string instrumentationKey, string exceptionMessage) => WriteEvent(33, origin, isAadEnabled, instrumentationKey, exceptionMessage);
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Parameters to this method are primitive and are trimmer safe.")]
         [Event(34, Message = "Exporter encountered a transmission failure and will wait {0} milliseconds before transmitting again.", Level = EventLevel.Warning)]
         public void BackoffEnabled(double milliseconds) => WriteEvent(34, milliseconds);
 
@@ -372,6 +380,7 @@ public void PartialContentResponseInvalid(int totalTelemetryItems, TelemetryErro
             }
         }
 
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "Parameters to this method are primitive and are trimmer safe.")]
         [Event(38, Message = "Received a partial success from ingestion that does not match telemetry that was sent. Total telemetry items sent: {0}. Error Index: {1}. Error StatusCode: {2}. Error Message: {3}", Level = EventLevel.Warning)]
         public void PartialContentResponseInvalid(int totalTelemetryItems, string errorIndex, string errorStatusCode, string errorMessage) => WriteEvent(38, totalTelemetryItems, errorIndex, errorStatusCode, errorMessage);
 

@@ -23,7 +23,13 @@ internal static class IngestionResponseHelper
 
                 var responseContent = response.Content.ToString();
 
-                var responseObj = JsonSerializer.Deserialize<ResponseObject>(responseContent);
+                ResponseObject? responseObj;
+
+#if NET6_0_OR_GREATER
+                responseObj = JsonSerializer.Deserialize<ResponseObject>(responseContent, SourceGenerationContext.Default.ResponseObject);
+#else
+                responseObj = JsonSerializer.Deserialize<ResponseObject>(responseContent);
+#endif
 
                 if (responseObj == null || responseObj.Errors == null)
                 {
@@ -39,7 +45,8 @@ internal static class IngestionResponseHelper
             }
         }
 
-        private class ResponseObject
+        // This class needs to be internal rather than private so that it can be used by the System.Text.Json source generator
+        internal class ResponseObject
         {
             [JsonPropertyName("itemsReceived")]
             public int ItemsReceived { get; set; }
@@ -51,7 +58,8 @@ private class ResponseObject
             public List<ErrorObject>? Errors { get; set; }
         }
 
-        private class ErrorObject
+        // This class needs to be internal rather than private so that it can be used by the System.Text.Json source generator
+        internal class ErrorObject
         {
             [JsonPropertyName("index")]
             public int Index { get; set; }

@@ -140,9 +140,17 @@ internal static string GetProblemId(Exception exception)
 
             if (exceptionStackFrame != null)
             {
-                MethodBase? methodBase = exceptionStackFrame.GetMethod();
+                MethodBase? methodBase = exceptionStackFrame.GetMethodWithoutWarning();
 
-                if (methodBase != null)
+                if (methodBase == null)
+                {
+                    // In an AOT scenario GetMethod() will return null.
+                    // Instead, call ToString() which gives a string like this:
+                    // "MethodName + 0x00 at offset 000 in file:line:column <filename unknown>:0:0"
+                    methodName = exceptionStackFrame.ToString();
+                    methodOffset = System.Diagnostics.StackFrame.OFFSET_UNKNOWN;
+                }
+                else
                 {
                     methodName = (methodBase.DeclaringType?.FullName ?? "Global") + "." + methodBase.Name;
                     methodOffset = exceptionStackFrame.GetILOffset();

@@ -0,0 +1,24 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using Azure.Monitor.OpenTelemetry.Exporter.Internals.Statsbeat;
+using System.Text.Json.Serialization;
+
+namespace Azure.Monitor.OpenTelemetry.Exporter.Internals;
+
+#if NET6_0_OR_GREATER
+// "Source Generation" is feature added to System.Text.Json in .NET 6.0.
+// This is a performance optimization that avoids runtime reflection when performing serialization.
+// Serialization metadata will be computed at compile-time and included in the assembly.
+// https://learn.microsoft.com/dotnet/standard/serialization/system-text-json/source-generation-modes
+// https://learn.microsoft.com/dotnet/standard/serialization/system-text-json/source-generation
+// https://devblogs.microsoft.com/dotnet/try-the-new-system-text-json-source-generator/
+[JsonSerializable(typeof(VmMetadataResponse))]
+[JsonSerializable(typeof(string))]
+[JsonSerializable(typeof(IngestionResponseHelper.ResponseObject))]
+[JsonSerializable(typeof(IngestionResponseHelper.ErrorObject))]
+[JsonSerializable(typeof(int))]
+internal partial class SourceGenerationContext : JsonSerializerContext
+{
+}
+#endif
@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
+using System.Runtime.CompilerServices;
+
+namespace Azure.Monitor.OpenTelemetry.Exporter.Internals
+{
+    internal static class StackFrameExtensions
+    {
+        /// <summary>
+        /// Wrapper for <see cref="System.Diagnostics.StackFrame.GetMethod"/>.
+        /// This method disables the Trimmer warning "IL2026:RequiresUnreferencedCode".
+        /// Callers MUST handle the null condition.
+        /// </summary>
+        /// <remarks>
+        /// In an AOT scenario GetMethod() will return null. Note this can happen even in non AOT scenarios.
+        /// Instead, call ToString() which gives a string like this:
+        /// "MethodName + 0x00 at offset 000 in file:line:column filename unknown:0:0".
+        /// </remarks>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification = "We will handle the null condition and call ToString() instead.")]
+        public static MethodBase? GetMethodWithoutWarning(this System.Diagnostics.StackFrame stackFrame) => stackFrame.GetMethod();
+    }
+}
@@ -133,7 +133,12 @@ private Measurement<int> GetAttachStatsbeat()
                     {
                         httpClient.DefaultRequestHeaders.Add("Metadata", "True");
                         var responseString = httpClient.GetStringAsync(StatsbeatConstants.AMS_Url);
-                        var vmMetadata = JsonSerializer.Deserialize<VmMetadataResponse>(responseString.Result);
+                        VmMetadataResponse? vmMetadata;
+#if NET6_0_OR_GREATER
+                        vmMetadata = JsonSerializer.Deserialize<VmMetadataResponse>(responseString.Result, SourceGenerationContext.Default.VmMetadataResponse);
+#else
+                        vmMetadata = JsonSerializer.Deserialize<VmMetadataResponse>(responseString.Result);
+#endif
 
                         return vmMetadata;
                     }

@@ -3,6 +3,7 @@
 
 namespace Azure.Monitor.OpenTelemetry.Exporter.Internals.Statsbeat
 {
+    // This class needs to be internal rather than private so that it can be used by the System.Text.Json source generator
     internal class VmMetadataResponse
     {
         public string? osType { get; set; }

@@ -0,0 +1,34 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>net7.0;net6.0;net462</TargetFrameworks>
+    <IsTestSupportProject>true</IsTestSupportProject>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(TargetFramework)' == 'net7.0'">
+    <PublishAot>true</PublishAot>
+    <TrimmerSingleWarn>false</TrimmerSingleWarn>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\core\Azure.Core\src\Azure.Core.csproj" />
+    <ProjectReference Include="..\..\src\Azure.Monitor.OpenTelemetry.Exporter.csproj" />
+
+    <!-- Update this dependency to its latest, which has all the annotations -->
+    <PackageReference Include="Microsoft.Extensions.Logging.Configuration" VersionOverride="8.0.0-rc.1.23419.4" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net7.0'">
+    <TrimmerRootAssembly Include="Azure.Monitor.OpenTelemetry.Exporter" />
+  </ItemGroup>
+
+  <!--Temp fix for "error : No files matching ;NU5105;CA1812;"-->
+  <!--Real fix coming in .NET 8 RC2: https://github.com/dotnet/runtime/issues/91965-->
+  <ItemGroup>
+    <_NoWarn Include="$(NoWarn)" />
+  </ItemGroup>
+  <PropertyGroup>
+    <NoWarn>@(_NoWarn)</NoWarn>
+  </PropertyGroup>
+
+</Project>
@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+namespace Azure.Monitor.OpenTelemetry.Exporter.AotCompatibilityTestApp;
+
+internal class Program
+{
+    public static void Main(string[] args)
+    {
+        System.Console.WriteLine("Hello, World!");
+    }
+}
@@ -0,0 +1,40 @@
+param([string]$targetNetFramework)
+
+dotnet restore
+$publishOutput = dotnet publish --framework net7.0 -nodeReuse:false /p:UseSharedCompilation=false /p:ExposeExperimentalFeatures=true
+
+if ($LASTEXITCODE -ne 0)
+{
+    Write-Host "Publish failed."
+    Write-Host $publishOutput
+    Exit 2
+}
+
+$actualWarningCount = 0
+
+foreach ($line in $($publishOutput -split "`r`n"))
+{
+    if ($line -like "*analysis warning IL*")
+    {
+        Write-Host $line
+
+        $actualWarningCount += 1
+    }
+}
+
+Write-Host "Actual warning count is:", $actualWarningCount
+$expectedWarningCount = 7
+# Known warnings:
+# - Azure.Core.Serialization.DynamicData: Using member 'Azure.Core.Serialization.DynamicData.DynamicDataJsonConverter.DynamicDataJsonConverter()'
+# - 4x Azure.RequestFailedException.TryExtractErrorContent(): Using member 'System.Text.Json.JsonSerializer.Deserialize<>()' (https://github.com/Azure/azure-sdk-for-net/pull/38996)
+# - Azure.Core.Json.MutableJsonDocument: Using member 'Azure.Core.Json.MutableJsonDocument.MutableJsonDocumentConverter.MutableJsonDocumentConverter()'
+# - Microsoft.Extensions.DependencyInjection.ServiceLookup.IEnumerableCallSite.ServiceType.get: Using member 'System.Type.MakeGenericType(Type[])
+
+$testPassed = 0
+if ($actualWarningCount -ne $expectedWarningCount)
+{
+    $testPassed = 1
+    Write-Host "Actual warning count:", $actualWarningCount, "is not as expected. Expected warning count is:", $expectedWarningCount
+}
+
+Exit $testPassed
@@ -98,11 +98,15 @@ public void TestNullMethodInfoInStack()
 #pragma warning restore CS8600 // Converting null literal or possible null value to non-nullable type.
 #pragma warning restore CS8625 // Cannot convert null literal to non-nullable reference type.
 
+            // In AOT, StackFrame.GetMethod() can return null.
+            // In this instance, we fall back to StackFrame.ToString()
+            frameMock.Setup(x => x.ToString()).Returns("MethodName + 0x00 at offset 000 in file:line:column <filename unknown>:0:0");
+
             Models.StackFrame stackFrame = new Models.StackFrame(frameMock.Object, 0);
 
             Assert.Equal("unknown", stackFrame.Assembly);
             Assert.Null(stackFrame.FileName);
-            Assert.Equal("unknown", stackFrame.Method);
+            Assert.Equal("MethodName + 0x00 at offset 000 in file:line:column <filename unknown>:0:0", stackFrame.Method);
             Assert.Null(stackFrame.Line);
         }