[DRAFT] fixing InMemoryExporter & Metrics bug. new class: ExportableMetricCopy. new ctor: InMemoryExporter(Func)

src/OpenTelemetry.Exporter.InMemory/.publicApi/net462/PublicAPI.Unshipped.txt

@@ -1,3 +1,18 @@
+OpenTelemetry.Exporter.InMemoryExporter<T>.AdditionalExportAction.get -> System.Action<T>
+OpenTelemetry.Exporter.InMemoryExporter<T>.AdditionalExportAction.set -> void
+OpenTelemetry.Exporter.InMemoryMetricExporter
+OpenTelemetry.Exporter.InMemoryMetricExporter.InMemoryMetricExporter(System.Collections.Generic.ICollection<OpenTelemetry.Metrics.ExportedMetric> exportedItems) -> void
+OpenTelemetry.Metrics.ExportableMetricCopy
+OpenTelemetry.Metrics.ExportableMetricCopy.Description.get -> string
+OpenTelemetry.Metrics.ExportableMetricCopy.MeterName.get -> string
+OpenTelemetry.Metrics.ExportableMetricCopy.MeterVersion.get -> string
+OpenTelemetry.Metrics.ExportableMetricCopy.MetricPoints.get -> System.Collections.Generic.IReadOnlyList<OpenTelemetry.Metrics.MetricPoint>
+OpenTelemetry.Metrics.ExportableMetricCopy.MetricType.get -> OpenTelemetry.Metrics.MetricType
+OpenTelemetry.Metrics.ExportableMetricCopy.Name.get -> string
+OpenTelemetry.Metrics.ExportableMetricCopy.Unit.get -> string
 OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions
+override OpenTelemetry.Exporter.InMemoryMetricExporter.Export(in OpenTelemetry.Batch<OpenTelemetry.Metrics.Metric> batch) -> OpenTelemetry.ExportResult
+static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.ExportableMetricCopy> exportedItems) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.ExportableMetricCopy> exportedItems, System.Action<OpenTelemetry.Metrics.MetricReaderOptions> configureMetricReader) -> OpenTelemetry.Metrics.MeterProviderBuilder
 static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.Metric> exportedItems) -> OpenTelemetry.Metrics.MeterProviderBuilder
-static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.Metric> exportedItems, System.Action<OpenTelemetry.Metrics.MetricReaderOptions> configureMetricReader) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.Metric> exportedItems, System.Action<OpenTelemetry.Metrics.MetricReaderOptions> configureMetricReader) -> OpenTelemetry.Metrics.MeterProviderBuilder

src/OpenTelemetry.Exporter.InMemory/.publicApi/netstandard2.0/PublicAPI.Unshipped.txt

@@ -1,3 +1,18 @@
+OpenTelemetry.Exporter.InMemoryExporter<T>.AdditionalExportAction.get -> System.Action<T>
+OpenTelemetry.Exporter.InMemoryExporter<T>.AdditionalExportAction.set -> void
+OpenTelemetry.Exporter.InMemoryMetricExporter
+OpenTelemetry.Exporter.InMemoryMetricExporter.InMemoryMetricExporter(System.Collections.Generic.ICollection<OpenTelemetry.Metrics.ExportedMetric> exportedItems) -> void
+OpenTelemetry.Metrics.ExportableMetricCopy
+OpenTelemetry.Metrics.ExportableMetricCopy.Description.get -> string
+OpenTelemetry.Metrics.ExportableMetricCopy.MeterName.get -> string
+OpenTelemetry.Metrics.ExportableMetricCopy.MeterVersion.get -> string
+OpenTelemetry.Metrics.ExportableMetricCopy.MetricPoints.get -> System.Collections.Generic.IReadOnlyList<OpenTelemetry.Metrics.MetricPoint>
+OpenTelemetry.Metrics.ExportableMetricCopy.MetricType.get -> OpenTelemetry.Metrics.MetricType
+OpenTelemetry.Metrics.ExportableMetricCopy.Name.get -> string
+OpenTelemetry.Metrics.ExportableMetricCopy.Unit.get -> string
 OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions
+override OpenTelemetry.Exporter.InMemoryMetricExporter.Export(in OpenTelemetry.Batch<OpenTelemetry.Metrics.Metric> batch) -> OpenTelemetry.ExportResult
+static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.ExportableMetricCopy> exportedItems) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.ExportableMetricCopy> exportedItems, System.Action<OpenTelemetry.Metrics.MetricReaderOptions> configureMetricReader) -> OpenTelemetry.Metrics.MeterProviderBuilder
 static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.Metric> exportedItems) -> OpenTelemetry.Metrics.MeterProviderBuilder
-static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.Metric> exportedItems, System.Action<OpenTelemetry.Metrics.MetricReaderOptions> configureMetricReader) -> OpenTelemetry.Metrics.MeterProviderBuilder
+static OpenTelemetry.Metrics.InMemoryExporterMetricsExtensions.AddInMemoryExporter(this OpenTelemetry.Metrics.MeterProviderBuilder builder, System.Collections.Generic.ICollection<OpenTelemetry.Metrics.Metric> exportedItems, System.Action<OpenTelemetry.Metrics.MetricReaderOptions> configureMetricReader) -> OpenTelemetry.Metrics.MeterProviderBuilder

src/OpenTelemetry.Exporter.InMemory/ExportableMetricCopy.cs

@@ -0,0 +1,58 @@
+// <copyright file="ExportableMetricCopy.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.Collections.Generic;
+
+namespace OpenTelemetry.Metrics
+{
+    /// <summary>
+    /// This class represents a selective copy of <see cref="Metric"/>.
+    /// This contains the minimum fields and properties needed for most
+    /// unit testing scenarios.
+    /// </summary>
+    public class ExportableMetricCopy
+    {
+        private readonly MetricStreamIdentity instrumentIdentity;
+
+        internal ExportableMetricCopy(Metric metric)
+        {
+            this.instrumentIdentity = metric.InstrumentIdentity;
+            this.MetricType = metric.MetricType;
+
+            List<MetricPoint> metricPoints = new();
+            foreach (ref readonly var metricPoint in metric.GetMetricPoints())
+            {
+                metricPoints.Add(metricPoint.Copy());
+            }
+
+            this.MetricPoints = metricPoints;
+        }
+
+        public string Name => this.instrumentIdentity.InstrumentName;
+
+        public string Description => this.instrumentIdentity.Description;
+
+        public string Unit => this.instrumentIdentity.Unit;
+
+        public string MeterName => this.instrumentIdentity.MeterName;
+
+        public MetricType MetricType { get; }
+
+        public string MeterVersion => this.instrumentIdentity.MeterVersion;
+
+        public IReadOnlyList<MetricPoint> MetricPoints { get; }
+    }
+}

src/OpenTelemetry.Exporter.InMemory/InMemoryExporter.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Exporter
@@ -28,16 +29,20 @@ public InMemoryExporter(ICollection<T> exportedItems)
             this.exportedItems = exportedItems;
         }
 
+        public Action<T> AdditionalExportAction { get; set; }
+
         public override ExportResult Export(in Batch<T> batch)
         {
-            if (this.exportedItems == null)
+            if (this.exportedItems == null && this.AdditionalExportAction == null)
             {
                 return ExportResult.Failure;
             }
 
             foreach (var data in batch)
             {
-                this.exportedItems.Add(data);
+                this.exportedItems?.Add(data);
+
+                this.AdditionalExportAction?.Invoke(data);
             }
 
             return ExportResult.Success;

src/OpenTelemetry.Exporter.InMemory/InMemoryExporterMetricsExtensions.cs

@@ -36,6 +36,10 @@ public static class InMemoryExporterMetricsExtensions
         /// <param name="builder"><see cref="MeterProviderBuilder"/> builder to use.</param>
         /// <param name="exportedItems">Collection which will be populated with the exported MetricItem.</param>
         /// <returns>The instance of <see cref="MeterProviderBuilder"/> to chain the calls.</returns>
+        /// <remarks>Note that when working with <see cref="Metric"/> these objects are not deep-cloned,
+        /// and repeated flushes may introduce duplicates.
+        /// If you need deep-cloned it is recommended to use <see cref="ExportableMetricCopy"/>.
+        /// </remarks>
         public static MeterProviderBuilder AddInMemoryExporter(this MeterProviderBuilder builder, ICollection<Metric> exportedItems)
         {
             Guard.ThrowIfNull(builder);
@@ -59,7 +63,62 @@ public static MeterProviderBuilder AddInMemoryExporter(this MeterProviderBuilder
         /// <param name="exportedItems">Collection which will be populated with the exported MetricItem.</param>
         /// <param name="configureMetricReader"><see cref="MetricReader"/> configuration options.</param>
         /// <returns>The instance of <see cref="MeterProviderBuilder"/> to chain the calls.</returns>
-        public static MeterProviderBuilder AddInMemoryExporter(this MeterProviderBuilder builder, ICollection<Metric> exportedItems, Action<MetricReaderOptions> configureMetricReader)
+        /// <remarks>Note that when working with <see cref="Metric"/> these objects are not deep-cloned,
+        /// and repeated flushes may introduce duplicates.
+        /// If you need deep-cloned it is recommended to use <see cref="ExportableMetricCopy"/>.
+        /// </remarks>
+        public static MeterProviderBuilder AddInMemoryExporter(
+            this MeterProviderBuilder builder,
+            ICollection<Metric> exportedItems,
+            Action<MetricReaderOptions> configureMetricReader)
+        {
+            Guard.ThrowIfNull(builder);
+            Guard.ThrowIfNull(exportedItems);
+
+            if (builder is IDeferredMeterProviderBuilder deferredMeterProviderBuilder)
+            {
+                return deferredMeterProviderBuilder.Configure((sp, builder) =>
+                {
+                    AddInMemoryExporter(builder, exportedItems, sp.GetOptions<MetricReaderOptions>(), configureMetricReader);
+                });
+            }
+
+            return AddInMemoryExporter(builder, exportedItems, new MetricReaderOptions(), configureMetricReader);
+        }
+
+        /// <summary>
+        /// Adds InMemory metric exporter to the <see cref="MeterProviderBuilder"/> using default options.
+        /// </summary>
+        /// <param name="builder"><see cref="MeterProviderBuilder"/> builder to use.</param>
+        /// <param name="exportedItems">Collection which will be populated with the exported MetricItem represented as <see cref="ExportableMetricCopy"/>.</param>
+        /// <returns>The instance of <see cref="MeterProviderBuilder"/> to chain the calls.</returns>
+        public static MeterProviderBuilder AddInMemoryExporter(this MeterProviderBuilder builder, ICollection<ExportableMetricCopy> exportedItems)
+        {
+            Guard.ThrowIfNull(builder);
+            Guard.ThrowIfNull(exportedItems);
+
+            if (builder is IDeferredMeterProviderBuilder deferredMeterProviderBuilder)
+            {
+                return deferredMeterProviderBuilder.Configure((sp, builder) =>
+                {
+                    AddInMemoryExporter(builder, exportedItems, sp.GetOptions<MetricReaderOptions>(), null);
+                });
+            }
+
+            return AddInMemoryExporter(builder, exportedItems, new MetricReaderOptions(), null);
+        }
+
+        /// <summary>
+        /// Adds InMemory metric exporter to the <see cref="MeterProviderBuilder"/> using default options.
+        /// </summary>
+        /// <param name="builder"><see cref="MeterProviderBuilder"/> builder to use.</param>
+        /// <param name="exportedItems">Collection which will be populated with the exported MetricItem represented as <see cref="ExportableMetricCopy"/>.</param>
+        /// <param name="configureMetricReader"><see cref="MetricReader"/> configuration options.</param>
+        /// <returns>The instance of <see cref="MeterProviderBuilder"/> to chain the calls.</returns>
+        public static MeterProviderBuilder AddInMemoryExporter(
+            this MeterProviderBuilder builder,
+            ICollection<ExportableMetricCopy> exportedItems,
+            Action<MetricReaderOptions> configureMetricReader)
         {
             Guard.ThrowIfNull(builder);
             Guard.ThrowIfNull(exportedItems);
@@ -93,5 +152,27 @@ private static MeterProviderBuilder AddInMemoryExporter(
 
             return builder.AddReader(metricReader);
         }
+
+        private static MeterProviderBuilder AddInMemoryExporter(
+            MeterProviderBuilder builder,
+            ICollection<ExportableMetricCopy> exportedItems,
+            MetricReaderOptions metricReaderOptions,
+            Action<MetricReaderOptions> configureMetricReader)
+        {
+            configureMetricReader?.Invoke(metricReaderOptions);
+
+            var metricExporter = new InMemoryExporter<Metric>(null)
+            {
+                AdditionalExportAction = metric => exportedItems.Add(new ExportableMetricCopy(metric)),
+            };
+
+            var metricReader = PeriodicExportingMetricReaderHelper.CreatePeriodicExportingMetricReader(
+                metricExporter,
+                metricReaderOptions,
+                DefaultExportIntervalMilliseconds,
+                DefaultExportTimeoutMilliseconds);
+
+            return builder.AddReader(metricReader);
+        }
     }
 }

src/OpenTelemetry.Exporter.InMemory/OpenTelemetry.Exporter.InMemory.csproj

@@ -27,8 +27,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <Compile Include="$(RepoRoot)\src\OpenTelemetry\Internal\PeriodicExportingMetricReaderHelper.cs" Link="Includes\PeriodicExportingMetricReaderHelper.cs" />
-    <Compile Include="$(RepoRoot)\src\OpenTelemetry\Internal\ServiceProviderExtensions.cs" Link="Includes\ServiceProviderExtensions.cs" />
+    <!--<Compile Include="$(RepoRoot)\src\OpenTelemetry\Internal\PeriodicExportingMetricReaderHelper.cs" Link="Includes\PeriodicExportingMetricReaderHelper.cs" />
+    <Compile Remove="C:\REPOS\opentelemetry-dotnet-fork\src\OpenTelemetry\Internal\ServiceProviderExtensions.cs" />
+    <Compile Include="$(RepoRoot)\src\OpenTelemetry\Internal\ServiceProviderExtensions.cs" Link="Includes\ServiceProviderExtensions.cs" />-->
     <Compile Include="$(RepoRoot)\src\OpenTelemetry.Api\Internal\Guard.cs" Link="Includes\Guard.cs" />
   </ItemGroup>
 

src/OpenTelemetry/AssemblyInfo.cs

@@ -20,5 +20,6 @@
 [assembly: InternalsVisibleTo("OpenTelemetry.Exporter.Prometheus" + AssemblyInfo.PublicKey)]
 [assembly: InternalsVisibleTo("OpenTelemetry.Exporter.Prometheus.Tests" + AssemblyInfo.PublicKey)]
 [assembly: InternalsVisibleTo("OpenTelemetry.Extensions.Hosting.Tests" + AssemblyInfo.PublicKey)]
+[assembly: InternalsVisibleTo("OpenTelemetry.Exporter.InMemory" + AssemblyInfo.PublicKey)]
 [assembly: InternalsVisibleTo("DynamicProxyGenAssembly2" + AssemblyInfo.MoqPublicKey)]
 [assembly: InternalsVisibleTo("Benchmarks" + AssemblyInfo.PublicKey)]

test/Benchmarks/Metrics/HistogramBenchmarks.cs

@@ -83,7 +83,7 @@ public void Setup()
                 this.bounds[i] = i * MaxValue / this.bounds.Length;
             }
 
-            var exportedItems = new List<Metric>();
+            var exportedItems = new List<ExportableMetricCopy>();
 
             this.provider = Sdk.CreateMeterProviderBuilder()
                 .AddMeter(this.meter.Name)

test/Benchmarks/Metrics/MetricsBenchmarks.cs

@@ -68,7 +68,7 @@ public void Setup()
         {
             this.meter = new Meter(Utils.GetCurrentMethodName());
 
-            var exportedItems = new List<Metric>();
+            var exportedItems = new List<ExportableMetricCopy>();
             this.provider = Sdk.CreateMeterProviderBuilder()
                 .AddMeter(this.meter.Name) // All instruments from this meter are enabled.
                 .AddInMemoryExporter(exportedItems, metricReaderOptions =>

test/Benchmarks/Metrics/MetricsViewBenchmarks.cs

@@ -45,7 +45,7 @@ public class MetricsViewBenchmarks
         private static readonly ThreadLocal<Random> ThreadLocalRandom = new(() => new Random());
         private static readonly string[] DimensionValues = new string[] { "DimVal1", "DimVal2", "DimVal3", "DimVal4", "DimVal5", "DimVal6", "DimVal7", "DimVal8", "DimVal9", "DimVal10" };
         private static readonly int DimensionsValuesLength = DimensionValues.Length;
-        private List<Metric> metrics;
+        private List<ExportableMetricCopy> metrics;
         private Counter<long> counter;
         private MeterProvider provider;
         private Meter meter;
@@ -81,7 +81,7 @@ public void Setup()
         {
             this.meter = new Meter(Utils.GetCurrentMethodName());
             this.counter = this.meter.CreateCounter<long>("counter");
-            this.metrics = new List<Metric>();
+            this.metrics = new List<ExportableMetricCopy>();
 
             if (this.ViewConfig == ViewConfiguration.NoView)
             {

test/OpenTelemetry.Instrumentation.AspNet.Tests/HttpInMetricsListenerTests.cs

@@ -49,7 +49,7 @@ public void HttpDurationMetricIsEmitted()
                 })
                 .Build();
 
-            var exportedItems = new List<Metric>();
+            var exportedItems = new List<ExportableMetricCopy>();
             using var meterprovider = Sdk.CreateMeterProviderBuilder()
                 .AddAspNetInstrumentation()
                 .AddInMemoryExporter(exportedItems)
@@ -61,7 +61,7 @@ public void HttpDurationMetricIsEmitted()
             meterprovider.ForceFlush();
 
             var metricPoints = new List<MetricPoint>();
-            foreach (var p in exportedItems[0].GetMetricPoints())
+            foreach (var p in exportedItems[0].MetricPoints)
             {
                 metricPoints.Add(p);
             }

test/OpenTelemetry.Instrumentation.AspNetCore.Tests/MetricTests.cs

@@ -55,7 +55,7 @@ public void AddAspNetCoreInstrumentation_BadArgs()
         [Fact]
         public async Task RequestMetricIsCaptured()
         {
-            var metricItems = new List<Metric>();
+            var metricItems = new List<ExportableMetricCopy>();
 
             this.meterProvider = Sdk.CreateMeterProviderBuilder()
                 .AddAspNetCoreInstrumentation()
@@ -85,7 +85,7 @@ public async Task RequestMetricIsCaptured()
             Assert.NotNull(metric);
             Assert.True(metric.MetricType == MetricType.Histogram);
             var metricPoints = new List<MetricPoint>();
-            foreach (var p in metric.GetMetricPoints())
+            foreach (var p in metric.MetricPoints)
             {
                 metricPoints.Add(p);
             }

test/OpenTelemetry.Instrumentation.Http.Tests/HttpClientTests.netcore31.cs

@@ -54,7 +54,7 @@ public async Task HttpOutCallsAreCollectedSuccessfullyAsync(HttpTestData.HttpOut
             var processor = new Mock<BaseProcessor<Activity>>();
             tc.Url = HttpTestData.NormalizeValues(tc.Url, host, port);
 
-            var metrics = new List<Metric>();
+            var metrics = new List<ExportableMetricCopy>();
 
             var meterProvider = Sdk.CreateMeterProviderBuilder()
                 .AddHttpClientInstrumentation()
@@ -146,7 +146,7 @@ public async Task HttpOutCallsAreCollectedSuccessfullyAsync(HttpTestData.HttpOut
                 Assert.True(metric.MetricType == MetricType.Histogram);
 
                 var metricPoints = new List<MetricPoint>();
-                foreach (var p in metric.GetMetricPoints())
+                foreach (var p in metric.MetricPoints)
                 {
                     metricPoints.Add(p);
                 }