Hosting: Support metrics registration via IServiceCollection & deferr…

…ed configuration (#2412)

* Add metrics support to hosting lib.

* Bug fixes and some public api additions.

* Added missing zipkin publicapi files.

* Unit tests.

* CHANGELOG updates

* Fixes

* Code review.

* Update src/OpenTelemetry.Extensions.Hosting/CHANGELOG.md

Co-authored-by: Reiley Yang <[email protected]>

* Code review.

* Warning fixup.

Co-authored-by: Reiley Yang <[email protected]>
Co-authored-by: Cijo Thomas <[email protected]>

docs/metrics/extending-the-sdk/Program.cs

@@ -29,10 +29,10 @@ public static void Main(string[] args)
     {
         using var meterProvider = Sdk.CreateMeterProviderBuilder()
             .AddSource("MyCompany.MyProduct.MyLibrary")
-            .AddMetricReader(new MyReader())
+            .AddReader(new MyReader())
             /** /
             TODO: revisit once this exception is removed "System.InvalidOperationException: Only one Metricreader is allowed.".
-            .AddMetricReader(new BaseExportingMetricReader(new MyExporter()))
+            .AddReader(new BaseExportingMetricReader(new MyExporter()))
             /**/
             .Build();
 

src/OpenTelemetry.Api/.publicApi/net461/PublicAPI.Unshipped.txt

@@ -7,6 +7,8 @@ OpenTelemetry.Context.RemotingRuntimeContextSlot<T>.Value.get -> object
 OpenTelemetry.Context.RemotingRuntimeContextSlot<T>.Value.set -> void
 OpenTelemetry.Context.ThreadLocalRuntimeContextSlot<T>.Value.get -> object
 OpenTelemetry.Context.ThreadLocalRuntimeContextSlot<T>.Value.set -> void
+OpenTelemetry.Metrics.IDeferredMeterProviderBuilder
+OpenTelemetry.Metrics.IDeferredMeterProviderBuilder.Configure(System.Action<System.IServiceProvider, OpenTelemetry.Metrics.MeterProviderBuilder> configure) -> OpenTelemetry.Metrics.MeterProviderBuilder
 override OpenTelemetry.Context.AsyncLocalRuntimeContextSlot<T>.Get() -> T
 override OpenTelemetry.Context.AsyncLocalRuntimeContextSlot<T>.Set(T value) -> void
 OpenTelemetry.Context.AsyncLocalRuntimeContextSlot<T>

src/OpenTelemetry.Api/.publicApi/netstandard2.0/PublicAPI.Unshipped.txt

@@ -5,6 +5,8 @@ OpenTelemetry.Context.IRuntimeContextSlotValueAccessor.Value.get -> object
 OpenTelemetry.Context.IRuntimeContextSlotValueAccessor.Value.set -> void
 OpenTelemetry.Context.ThreadLocalRuntimeContextSlot<T>.Value.get -> object
 OpenTelemetry.Context.ThreadLocalRuntimeContextSlot<T>.Value.set -> void
+OpenTelemetry.Metrics.IDeferredMeterProviderBuilder
+OpenTelemetry.Metrics.IDeferredMeterProviderBuilder.Configure(System.Action<System.IServiceProvider, OpenTelemetry.Metrics.MeterProviderBuilder> configure) -> OpenTelemetry.Metrics.MeterProviderBuilder
 static OpenTelemetry.Context.RuntimeContext.GetValue(string slotName) -> object
 static OpenTelemetry.Context.RuntimeContext.GetValue<T>(string slotName) -> T
 static OpenTelemetry.Context.RuntimeContext.SetValue(string slotName, object value) -> void

src/OpenTelemetry.Api/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+* Added `IDeferredMeterProviderBuilder`
+  ([#2412](https://github.com/open-telemetry/opentelemetry-dotnet/pull/2412))
+
 ## 1.2.0-alpha4
 
 Released 2021-Sep-23

src/OpenTelemetry.Api/Metrics/IDeferredMeterProviderBuilder.cs

@@ -0,0 +1,36 @@
+// <copyright file="IDeferredMeterProviderBuilder.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System;
+
+namespace OpenTelemetry.Metrics
+{
+    /// <summary>
+    /// Describes a meter provider builder that supports deferred initialization
+    /// using an <see cref="IServiceProvider"/> to perform dependency injection.
+    /// </summary>
+    public interface IDeferredMeterProviderBuilder
+    {
+        /// <summary>
+        /// Register a callback action to configure the <see
+        /// cref="MeterProviderBuilder"/> once the application <see
+        /// cref="IServiceProvider"/> is available.
+        /// </summary>
+        /// <param name="configure">Configuration callback.</param>
+        /// <returns>The supplied <see cref="MeterProviderBuilder"/> for chaining.</returns>
+        MeterProviderBuilder Configure(Action<IServiceProvider, MeterProviderBuilder> configure);
+    }
+}

src/OpenTelemetry.Exporter.Console/ConsoleExporterMetricsExtensions.cs

@@ -43,10 +43,10 @@ public static MeterProviderBuilder AddConsoleExporter(this MeterProviderBuilder
 
             if (options.MetricExportIntervalMilliseconds == Timeout.Infinite)
             {
-                return builder.AddMetricReader(new BaseExportingMetricReader(exporter));
+                return builder.AddReader(new BaseExportingMetricReader(exporter));
             }
 
-            return builder.AddMetricReader(new PeriodicExportingMetricReader(exporter, options.MetricExportIntervalMilliseconds));
+            return builder.AddReader(new PeriodicExportingMetricReader(exporter, options.MetricExportIntervalMilliseconds));
         }
     }
 }

src/OpenTelemetry.Exporter.InMemory/InMemoryExporterMetricsExtensions.cs

@@ -40,7 +40,7 @@ public static MeterProviderBuilder AddInMemoryExporter(this MeterProviderBuilder
                 throw new ArgumentNullException(nameof(exportedItems));
             }
 
-            return builder.AddMetricReader(new BaseExportingMetricReader(new InMemoryExporter<Metric>(exportedItems)));
+            return builder.AddReader(new BaseExportingMetricReader(new InMemoryExporter<Metric>(exportedItems)));
         }
     }
 }

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpMetricExporterExtensions.cs

@@ -42,7 +42,7 @@ public static MeterProviderBuilder AddOtlpExporter(this MeterProviderBuilder bui
 
             var metricExporter = new OtlpMetricsExporter(options);
             var metricReader = new PeriodicExportingMetricReader(metricExporter, options.MetricExportIntervalMilliseconds);
-            return builder.AddMetricReader(metricReader);
+            return builder.AddReader(metricReader);
         }
     }
 }

src/OpenTelemetry.Exporter.Prometheus/MeterProviderBuilderExtensions.cs

@@ -43,7 +43,7 @@ public static MeterProviderBuilder AddPrometheusExporter(this MeterProviderBuild
 
             var metricsHttpServer = new PrometheusExporterMetricsHttpServer(exporter);
             metricsHttpServer.Start();
-            return builder.AddMetricReader(reader);
+            return builder.AddReader(reader);
         }
     }
 }

src/OpenTelemetry.Exporter.Zipkin/.publicApi/net5.0/PublicAPI.Shipped.txt

@@ -0,0 +1,17 @@
+OpenTelemetry.Exporter.ZipkinExporter
+OpenTelemetry.Exporter.ZipkinExporter.ZipkinExporter(OpenTelemetry.Exporter.ZipkinExporterOptions options, System.Net.Http.HttpClient client = null) -> void
+OpenTelemetry.Exporter.ZipkinExporterOptions
+OpenTelemetry.Exporter.ZipkinExporterOptions.BatchExportProcessorOptions.get -> OpenTelemetry.BatchExportProcessorOptions<System.Diagnostics.Activity>
+OpenTelemetry.Exporter.ZipkinExporterOptions.BatchExportProcessorOptions.set -> void
+OpenTelemetry.Exporter.ZipkinExporterOptions.Endpoint.get -> System.Uri
+OpenTelemetry.Exporter.ZipkinExporterOptions.Endpoint.set -> void
+OpenTelemetry.Exporter.ZipkinExporterOptions.ExportProcessorType.get -> OpenTelemetry.ExportProcessorType
+OpenTelemetry.Exporter.ZipkinExporterOptions.ExportProcessorType.set -> void
+OpenTelemetry.Exporter.ZipkinExporterOptions.MaxPayloadSizeInBytes.get -> int?
+OpenTelemetry.Exporter.ZipkinExporterOptions.MaxPayloadSizeInBytes.set -> void
+OpenTelemetry.Exporter.ZipkinExporterOptions.UseShortTraceIds.get -> bool
+OpenTelemetry.Exporter.ZipkinExporterOptions.UseShortTraceIds.set -> void
+OpenTelemetry.Exporter.ZipkinExporterOptions.ZipkinExporterOptions() -> void
+OpenTelemetry.Trace.ZipkinExporterHelperExtensions
+override OpenTelemetry.Exporter.ZipkinExporter.Export(in OpenTelemetry.Batch<System.Diagnostics.Activity> batch) -> OpenTelemetry.ExportResult
+static OpenTelemetry.Trace.ZipkinExporterHelperExtensions.AddZipkinExporter(this OpenTelemetry.Trace.TracerProviderBuilder builder, System.Action<OpenTelemetry.Exporter.ZipkinExporterOptions> configure = null) -> OpenTelemetry.Trace.TracerProviderBuilder

src/OpenTelemetry.Extensions.Hosting/.publicApi/netstandard2.0/PublicAPI.Unshipped.txt

@@ -1,7 +1,15 @@
 Microsoft.Extensions.DependencyInjection.OpenTelemetryServicesExtensions
+OpenTelemetry.Metrics.MeterProviderBuilderExtensions
 OpenTelemetry.Trace.TracerProviderBuilderExtensions
+static Microsoft.Extensions.DependencyInjection.OpenTelemetryServicesExtensions.AddOpenTelemetryMetrics(this Microsoft.Extensions.DependencyInjection.IServiceCollection services) -> Microsoft.Extensions.DependencyInjection.IServiceCollection
+static Microsoft.Extensions.DependencyInjection.OpenTelemetryServicesExtensions.AddOpenTelemetryMetrics(this Microsoft.Extensions.DependencyInjection.IServiceCollection services, System.Action<OpenTelemetry.Metrics.MeterProviderBuilder> configure) -> Microsoft.Extensions.DependencyInjection.IServiceCollection
 static Microsoft.Extensions.DependencyInjection.OpenTelemetryServicesExtensions.AddOpenTelemetryTracing(this Microsoft.Extensions.DependencyInjection.IServiceCollection services) -> Microsoft.Extensions.DependencyInjection.IServiceCollection
 static Microsoft.Extensions.DependencyInjection.OpenTelemetryServicesExtensions.AddOpenTelemetryTracing(this Microsoft.Extensions.DependencyInjection.IServiceCollection services, System.Action<OpenTelemetry.Trace.TracerProviderBuilder> configure) -> Microsoft.Extensions.DependencyInjection.IServiceCollection
+static OpenTelemetry.Metrics.MeterProviderBuilderExtensions.AddInstrumentation<T>(this OpenTelemetry.Metrics.MeterProviderBuilder meterProviderBuilder) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static OpenTelemetry.Metrics.MeterProviderBuilderExtensions.AddReader<T>(this OpenTelemetry.Metrics.MeterProviderBuilder meterProviderBuilder) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static OpenTelemetry.Metrics.MeterProviderBuilderExtensions.Build(this OpenTelemetry.Metrics.MeterProviderBuilder meterProviderBuilder, System.IServiceProvider serviceProvider) -> OpenTelemetry.Metrics.MeterProvider
+static OpenTelemetry.Metrics.MeterProviderBuilderExtensions.Configure(this OpenTelemetry.Metrics.MeterProviderBuilder meterProviderBuilder, System.Action<System.IServiceProvider, OpenTelemetry.Metrics.MeterProviderBuilder> configure) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static OpenTelemetry.Metrics.MeterProviderBuilderExtensions.GetServices(this OpenTelemetry.Metrics.MeterProviderBuilder meterProviderBuilder) -> Microsoft.Extensions.DependencyInjection.IServiceCollection
 static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddInstrumentation<T>(this OpenTelemetry.Trace.TracerProviderBuilder tracerProviderBuilder) -> OpenTelemetry.Trace.TracerProviderBuilder
 static OpenTelemetry.Trace.TracerProviderBuilderExtensions.AddProcessor<T>(this OpenTelemetry.Trace.TracerProviderBuilder tracerProviderBuilder) -> OpenTelemetry.Trace.TracerProviderBuilder
 static OpenTelemetry.Trace.TracerProviderBuilderExtensions.Build(this OpenTelemetry.Trace.TracerProviderBuilder tracerProviderBuilder, System.IServiceProvider serviceProvider) -> OpenTelemetry.Trace.TracerProvider

src/OpenTelemetry.Extensions.Hosting/CHANGELOG.md

@@ -5,6 +5,12 @@
 * Removes upper constraint for Microsoft.Extensions.Hosting.Abstractions
   dependency. ([#2179](https://github.com/open-telemetry/opentelemetry-dotnet/pull/2179))
 
+* Added `AddOpenTelemetryMetrics` extensions on `IServiceCollection` to register
+  OpenTelemetry `MeterProvider` with application services. Added
+  `AddInstrumentation<T>`, `AddReader<T>`, and `Configure` extensions on
+  `MeterProviderBuilder` to support dependency injection scenarios.
+  ([#2412](https://github.com/open-telemetry/opentelemetry-dotnet/pull/2412))
+
 ## 1.0.0-rc7
 
 Released 2021-Jul-12

src/OpenTelemetry.Extensions.Hosting/Implementation/MeterProviderBuilderHosting.cs

@@ -0,0 +1,65 @@
+// <copyright file="MeterProviderBuilderHosting.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System;
+using System.Collections.Generic;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace OpenTelemetry.Metrics
+{
+    /// <summary>
+    /// A <see cref="MeterProviderBuilderBase"/> with support for deferred initialization using <see cref="IServiceProvider"/> for dependency injection.
+    /// </summary>
+    internal sealed class MeterProviderBuilderHosting : MeterProviderBuilderBase, IDeferredMeterProviderBuilder
+    {
+        private readonly List<Action<IServiceProvider, MeterProviderBuilder>> configurationActions = new List<Action<IServiceProvider, MeterProviderBuilder>>();
+
+        public MeterProviderBuilderHosting(IServiceCollection services)
+        {
+            this.Services = services ?? throw new ArgumentNullException(nameof(services));
+        }
+
+        public IServiceCollection Services { get; }
+
+        public MeterProviderBuilder Configure(Action<IServiceProvider, MeterProviderBuilder> configure)
+        {
+            if (configure == null)
+            {
+                throw new ArgumentNullException(nameof(configure));
+            }
+
+            this.configurationActions.Add(configure);
+            return this;
+        }
+
+        public MeterProvider Build(IServiceProvider serviceProvider)
+        {
+            if (serviceProvider == null)
+            {
+                throw new ArgumentNullException(nameof(serviceProvider));
+            }
+
+            // Note: Not using a foreach loop because additional actions can be
+            // added during each call.
+            for (int i = 0; i < this.configurationActions.Count; i++)
+            {
+                this.configurationActions[i](serviceProvider, this);
+            }
+
+            return this.Build();
+        }
+    }
+}

src/OpenTelemetry.Extensions.Hosting/Implementation/TelemetryHostedService.cs

@@ -19,6 +19,7 @@
 using System.Threading.Tasks;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
+using OpenTelemetry.Metrics;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Extensions.Hosting.Implementation
@@ -36,12 +37,15 @@ public Task StartAsync(CancellationToken cancellationToken)
         {
             try
             {
-                // The sole purpose of this HostedService is to ensure
-                // all instrumentations are created and started.
-                // This method is invoked when host starts, and
-                // by requesting the TracerProvider from DI
-                // it ensures all instrumentations gets started.
-                this.serviceProvider.GetRequiredService<TracerProvider>();
+                // The sole purpose of this HostedService is to ensure all
+                // instrumentations, exporters, etc., are created and started.
+                var meterProvider = this.serviceProvider.GetService<MeterProvider>();
+                var tracerProvider = this.serviceProvider.GetService<TracerProvider>();
+
+                if (meterProvider == null && tracerProvider == null)
+                {
+                    throw new InvalidOperationException("Could not resolve either MeterProvider or TracerProvider through application ServiceProvider, OpenTelemetry SDK has not been initialized.");
+                }
             }
             catch (Exception ex)
             {

src/OpenTelemetry.Extensions.Hosting/Implementation/TracerProviderBuilderHosting.cs

@@ -47,10 +47,16 @@ public TracerProviderBuilder Configure(Action<IServiceProvider, TracerProviderBu
 
         public TracerProvider Build(IServiceProvider serviceProvider)
         {
-            int i = 0;
-            while (i < this.configurationActions.Count)
+            if (serviceProvider == null)
             {
-                this.configurationActions[i++](serviceProvider, this);
+                throw new ArgumentNullException(nameof(serviceProvider));
+            }
+
+            // Note: Not using a foreach loop because additional actions can be
+            // added during each call.
+            for (int i = 0; i < this.configurationActions.Count; i++)
+            {
+                this.configurationActions[i](serviceProvider, this);
             }
 
             return this.Build();