OTLP exporter: use Grpc.Net.Client for netstandard2.1 (#1662)

* Use Grpc.Net.Client for netstandard2.1

* Fix AspNetCore example app

* Better comment for Http2UnencryptedSupport switch

* Update PublicAPI

* Update changelog

* Fix line endings

* Suppress instrumentation on export

Co-authored-by: Cijo Thomas <cithomas@microsoft.com>

build/Common.nonprod.props

@@ -28,7 +28,6 @@
     <GoogleProtobufPkgVer>[3.13.0,4.0)</GoogleProtobufPkgVer>
     <GrpcAspNetCorePkgVer>[2.27.0,3.0)</GrpcAspNetCorePkgVer>
     <GrpcAspNetCoreServerPkgVer>[2.30.0, 3.0)</GrpcAspNetCoreServerPkgVer>
-    <GrpcNetClientPkgVer>[2.32.0,3.0)</GrpcNetClientPkgVer>
     <GrpcToolsPkgVer>[2.25.0,3.0)</GrpcToolsPkgVer>
     <MicrosoftAspNetMvcPkgVer>[5.2.7,6.0)</MicrosoftAspNetMvcPkgVer>
     <MicrosoftAspNetWebApiWebHostPkgVer>[5.2.7,6.0)</MicrosoftAspNetWebApiWebHostPkgVer>

build/Common.props

@@ -24,6 +24,7 @@
     <MinVerPkgVer>[2.3.0,3.0)</MinVerPkgVer>
     <GoogleProtobufPkgVer>[3.6.1,4.0)</GoogleProtobufPkgVer>
     <GrpcPkgVer>[2.23.0,3.0)</GrpcPkgVer>
+    <GrpcNetClientPkgVer>[2.32.0,3.0)</GrpcNetClientPkgVer>
     <GrpcToolsPkgVer>[2.25.0,3.0)</GrpcToolsPkgVer>
     <MicrosoftAspNetCoreHttpAbstractionsPkgVer>[2.1.1,6.0)</MicrosoftAspNetCoreHttpAbstractionsPkgVer>
     <MicrosoftAspNetCoreHttpFeaturesPkgVer>[2.1.1,6.0)</MicrosoftAspNetCoreHttpFeaturesPkgVer>

examples/AspNetCore/Startup.cs

@@ -80,13 +80,18 @@ namespace Examples.AspNetCore
                         }));
                     break;
                 case "otlp":
+                    // Adding the OtlpExporter creates a GrpcChannel.
+                    // This switch must be set before creating a GrpcChannel/HttpClient when calling an insecure gRPC service.
+                    // See: https://docs.microsoft.com/aspnet/core/grpc/troubleshoot#call-insecure-grpc-services-with-net-core-client
+                    AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
+
                     services.AddOpenTelemetryTracing((builder) => builder
                         .SetResourceBuilder(ResourceBuilder.CreateDefault().AddService(this.Configuration.GetValue<string>("Otlp:ServiceName")))
                         .AddAspNetCoreInstrumentation()
                         .AddHttpClientInstrumentation()
                         .AddOtlpExporter(otlpOptions =>
                         {
-                            otlpOptions.Endpoint = this.Configuration.GetValue<string>("Otlp:Endpoint");
+                            otlpOptions.Endpoint = new Uri(this.Configuration.GetValue<string>("Otlp:Endpoint"));
                         }));
                     break;
                 default:

examples/Console/Program.cs

@@ -133,7 +133,7 @@ namespace Examples.Console
     [Verb("otlp", HelpText = "Specify the options required to test OpenTelemetry Protocol (OTLP)")]
     internal class OtlpOptions
     {
-        [Option('e', "endpoint", HelpText = "Target to which the exporter is going to send traces or metrics", Default = "localhost:55680")]
+        [Option('e', "endpoint", HelpText = "Target to which the exporter is going to send traces or metrics", Default = "http://localhost:55680")]
         public string Endpoint { get; set; }
     }
 

examples/Console/TestOtlpExporter.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry;
 using OpenTelemetry.Resources;
 using OpenTelemetry.Trace;
@@ -53,12 +54,17 @@ namespace Examples.Console
 
         private static object RunWithActivitySource(string endpoint)
         {
+            // Adding the OtlpExporter creates a GrpcChannel.
+            // This switch must be set before creating a GrpcChannel/HttpClient when calling an insecure gRPC service.
+            // See: https://docs.microsoft.com/aspnet/core/grpc/troubleshoot#call-insecure-grpc-services-with-net-core-client
+            AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
+
             // Enable OpenTelemetry for the sources "Samples.SampleServer" and "Samples.SampleClient"
             // and use OTLP exporter.
             using var openTelemetry = Sdk.CreateTracerProviderBuilder()
                     .AddSource("Samples.SampleClient", "Samples.SampleServer")
                     .SetResourceBuilder(ResourceBuilder.CreateDefault().AddService("otlp-test"))
-                    .AddOtlpExporter(opt => opt.Endpoint = endpoint)
+                    .AddOtlpExporter(opt => opt.Endpoint = new Uri(endpoint))
                     .Build();
 
             // The above line is required only in Applications

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/.publicApi/netstandard2.1/PublicAPI.Unshipped.txt

@@ -0,0 +1,18 @@
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporter
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporter.OtlpExporter(OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions options) -> void
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.BatchExportProcessorOptions.get -> OpenTelemetry.BatchExportProcessorOptions<System.Diagnostics.Activity>
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.BatchExportProcessorOptions.set -> void
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.GrpcChannelOptions.get -> Grpc.Net.Client.GrpcChannelOptions
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.GrpcChannelOptions.set -> void
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.Endpoint.get -> System.Uri
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.Endpoint.set -> void
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.ExportProcessorType.get -> OpenTelemetry.ExportProcessorType
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.ExportProcessorType.set -> void
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.Headers.get -> Grpc.Core.Metadata
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.Headers.set -> void
+OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions.OtlpExporterOptions() -> void
+OpenTelemetry.Trace.OtlpExporterHelperExtensions
+override OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporter.Export(in OpenTelemetry.Batch<System.Diagnostics.Activity> activityBatch) -> OpenTelemetry.ExportResult
+override OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporter.OnShutdown(int timeoutMilliseconds) -> bool
+static OpenTelemetry.Trace.OtlpExporterHelperExtensions.AddOtlpExporter(this OpenTelemetry.Trace.TracerProviderBuilder builder, System.Action<OpenTelemetry.Exporter.OpenTelemetryProtocol.OtlpExporterOptions> configure = null) -> OpenTelemetry.Trace.TracerProviderBuilder

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/CHANGELOG.md

@@ -8,6 +8,13 @@
 * In `OtlpExporterOptions.cs`: Exporter options now include a switch for
   Batch vs Simple exporter, and settings for batch exporting properties.
 
+* Introduce a `netstandard2.1` build enabling the exporter to use the
+  [gRPC for .NET](https://github.com/grpc/grpc-dotnet) library instead of the
+  [gRPC for C#](https://github.com/grpc/grpc/tree/master/src/csharp) library
+  for .NET Core 3.0+ applications. This required some breaking changes to the
+  `OtlpExporterOptions`.
+  ([#1662](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1662))
+
 ## 1.0.0-rc1.1
 
 Released 2020-Nov-17

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OpenTelemetry.Exporter.OpenTelemetryProtocol.csproj

@@ -1,14 +1,21 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net452;net46;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>net452;net46;netstandard2.0;netstandard2.1</TargetFrameworks>
     <Description>OpenTelemetry protocol exporter for OpenTelemetry .NET</Description>
     <PackageTags>$(PackageTags);OTLP</PackageTags>
   </PropertyGroup>
 
+  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.1'">
+    <PackageReference Include="Grpc.Net.Client" Version="$(GrpcNetClientPkgVer)" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' != 'netstandard2.1'">
+    <PackageReference Include="Grpc" Version="$(GrpcPkgVer)" />
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="$(RepoRoot)\src\OpenTelemetry\OpenTelemetry.csproj" />
     <PackageReference Include="Google.Protobuf" Version="$(GoogleProtobufPkgVer)" />
-    <PackageReference Include="Grpc" Version="$(GrpcPkgVer)" />
     <PackageReference Include="Grpc.Tools" Version="$(GrpcToolsPkgVer)" PrivateAssets="all" />
 
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Api\Internal\ExceptionExtensions.cs" Link="Includes\ExceptionExtensions.cs" />

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpExporter.cs

@@ -20,6 +20,9 @@ using System.Diagnostics;
 using System.Linq;
 using System.Threading.Tasks;
 using Grpc.Core;
+#if NETSTANDARD2_1
+using Grpc.Net.Client;
+#endif
 using OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation;
 using OpenTelemetry.Resources;
 using OtlpCollector = Opentelemetry.Proto.Collector.Trace.V1;
@@ -37,7 +40,11 @@ namespace OpenTelemetry.Exporter.OpenTelemetryProtocol
         private const string DefaultServiceName = "OpenTelemetry Exporter";
 
         private readonly OtlpExporterOptions options;
+#if NETSTANDARD2_1
+        private readonly GrpcChannel channel;
+#else
         private readonly Channel channel;
+#endif
         private readonly OtlpCollector.TraceService.ITraceServiceClient traceClient;
         private readonly Metadata headers;
 
@@ -65,7 +72,13 @@ namespace OpenTelemetry.Exporter.OpenTelemetryProtocol
             }
             else
             {
+#if NETSTANDARD2_1
+                this.channel = options.GrpcChannelOptions == default
+                    ? GrpcChannel.ForAddress(options.Endpoint)
+                    : GrpcChannel.ForAddress(options.Endpoint, options.GrpcChannelOptions);
+#else
                 this.channel = new Channel(options.Endpoint, options.Credentials, options.ChannelOptions);
+#endif
                 this.traceClient = new OtlpCollector.TraceService.TraceServiceClient(this.channel);
             }
         }
@@ -80,6 +93,9 @@ namespace OpenTelemetry.Exporter.OpenTelemetryProtocol
                 this.SetResource(this.ParentProvider.GetResource());
             }
 
+            // Prevents the exporter's gRPC and HTTP operations from being instrumented.
+            using var scope = SuppressInstrumentationScope.Begin();
+
             OtlpCollector.ExportTraceServiceRequest request = new OtlpCollector.ExportTraceServiceRequest();
 
             request.AddBatch(this.ProcessResource, activityBatch);

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpExporterOptions.cs

@@ -14,9 +14,13 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using Grpc.Core;
+#if NETSTANDARD2_1
+using Grpc.Net.Client;
+#endif
 
 namespace OpenTelemetry.Exporter.OpenTelemetryProtocol
 {
@@ -25,27 +29,42 @@ namespace OpenTelemetry.Exporter.OpenTelemetryProtocol
     /// </summary>
     public class OtlpExporterOptions
     {
+#if NETSTANDARD2_1
+        /// <summary>
+        /// Gets or sets the target to which the exporter is going to send traces or metrics.
+        /// The valid syntax is described at https://github.com/grpc/grpc/blob/master/doc/naming.md.
+        /// </summary>
+        public Uri Endpoint { get; set; } = new Uri("http://localhost:55680");
+#else
         /// <summary>
         /// Gets or sets the target to which the exporter is going to send traces or metrics.
         /// The valid syntax is described at https://github.com/grpc/grpc/blob/master/doc/naming.md.
         /// </summary>
         public string Endpoint { get; set; } = "localhost:55680";
+#endif
 
+#if NETSTANDARD2_1
+        /// <summary>
+        /// Gets or sets the gRPC channel options.
+        /// </summary>
+        public GrpcChannelOptions GrpcChannelOptions { get; set; }
+#else
         /// <summary>
         /// Gets or sets the client-side channel credentials. Used for creation of a secure channel.
         /// The default is "insecure". See detais at https://grpc.io/docs/guides/auth/#credential-types.
         /// </summary>
         public ChannelCredentials Credentials { get; set; } = ChannelCredentials.Insecure;
 
-        /// <summary>
-        /// Gets or sets optional headers for the connection.
-        /// </summary>
-        public Metadata Headers { get; set; } = new Metadata();
-
         /// <summary>
         /// Gets or sets the gRPC channel options.
         /// </summary>
         public IEnumerable<ChannelOption> ChannelOptions { get; set; }
+#endif
+
+        /// <summary>
+        /// Gets or sets optional headers for the connection.
+        /// </summary>
+        public Metadata Headers { get; set; } = new Metadata();
 
         /// <summary>
         /// Gets or sets the export processor type to be used with the OpenTelemetry Protocol Exporter.