Implement the metrics dispose/shutdown logic (#2404)

OpenTelemetry.sln

@@ -218,7 +218,7 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "getting-started-observable-
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "getting-started-observable-counter", "docs\metrics\getting-started-observable-counter\getting-started-observable-counter.csproj", "{43005998-0247-4620-AF88-27DACD48712E}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "getting-started-counter", "docs\metrics\getting-started-counter\getting-started-counter.csproj", "{EA60B549-F712-4ABE-8E44-FCA83B78C06E}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "getting-started", "docs\metrics\getting-started\getting-started.csproj", "{EA60B549-F712-4ABE-8E44-FCA83B78C06E}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "extending-the-sdk", "docs\metrics\extending-the-sdk\extending-the-sdk.csproj", "{1F9D7748-D099-4E25-97F5-9C969D6FF969}"
 EndProject

README.md

@@ -24,7 +24,7 @@ Any exceptions to this are noted in the individual `README.md` files.
 If you are new here, please read the getting started docs:
 
 * [logs](./docs/logs/getting-started/README.md)
-* [metrics](./docs/metrics/README.md) (experimental)
+* [metrics](./docs/metrics/getting-started/README.md) (experimental)
 * [trace](./docs/trace/getting-started/README.md)
 
 This repository includes multiple installable components, available on

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

@@ -36,11 +36,12 @@ protected override bool ProcessMetrics(Batch<Metric> metrics, int timeoutMillise
     protected override bool OnShutdown(int timeoutMilliseconds)
     {
         Console.WriteLine($"{this.name}.OnShutdown(timeoutMilliseconds={timeoutMilliseconds})");
-        return true;
+        return base.OnShutdown(timeoutMilliseconds);
     }
 
     protected override void Dispose(bool disposing)
     {
         Console.WriteLine($"{this.name}.Dispose({disposing})");
+        base.Dispose(disposing);
     }
 }

docs/metrics/getting-started-counter/Program.cs → docs/metrics/getting-started/Program.cs

@@ -29,11 +29,13 @@ public static void Main(string[] args)
             .AddConsoleExporter()
             .Build();
 
-        var counter = MyMeter.CreateCounter<long>("MyCounter");
+        var counter = MyMeter.CreateCounter<long>("MyFruitCounter");
 
-        for (int i = 0; i < 20000000; i++)
-        {
-            counter.Add(1, new("tag1", "value1"), new("tag2", "value2"));
-        }
+        counter.Add(1, new("name", "apple"), new("color", "red"));
+        counter.Add(2, new("name", "lemon"), new("color", "yellow"));
+        counter.Add(1, new("name", "lemon"), new("color", "yellow"));
+        counter.Add(2, new("name", "apple"), new("color", "green"));
+        counter.Add(5, new("name", "apple"), new("color", "red"));
+        counter.Add(4, new("name", "lemon"), new("color", "yellow"));
     }
 }

docs/metrics/getting-started-counter/README.md → docs/metrics/getting-started/README.md

@@ -6,8 +6,8 @@ SDK](https://dotnet.microsoft.com/download) on your computer.
 Create a new console application and run it:
 
 ```sh
-dotnet new console --output getting-started-counter
-cd getting-started-counter
+dotnet new console --output getting-started
+cd getting-started
 dotnet run
 ```
 
@@ -32,29 +32,13 @@ output from the console, similar to shown below:
 
 <!-- markdownlint-disable MD013 -->
 ```text
-Export MyCounter, Meter: MyCompany.MyProduct.MyLibrary/1.0
-(2021-09-03T04:29:37.1096398Z, 2021-09-03T04:29:38.0649233Z] tag1:value1tag2:value2 LongSum
-Value: 460
-
-Export MyCounter, Meter: MyCompany.MyProduct.MyLibrary/1.0
-(2021-09-03T04:29:38.0649233Z, 2021-09-03T04:29:39.1483639Z] tag1:value1tag2:value2 LongSum
-Value: 640
-
-Export MyCounter, Meter: MyCompany.MyProduct.MyLibrary/1.0
-(2021-09-03T04:29:39.1483639Z, 2021-09-03T04:29:40.1679696Z] tag1:value1tag2:value2 LongSum
-Value: 420
-
-Export MyCounter, Meter: MyCompany.MyProduct.MyLibrary/1.0
-(2021-09-03T04:29:40.1679696Z, 2021-09-03T04:29:41.1774527Z] tag1:value1tag2:value2 LongSum
-Value: 560
-
-Export MyCounter, Meter: MyCompany.MyProduct.MyLibrary/1.0
-(2021-09-03T04:29:41.1774527Z, 2021-09-03T04:29:42.1791523Z] tag1:value1tag2:value2 LongSum
-Value: 650
-
-Export MyCounter, Meter: MyCompany.MyProduct.MyLibrary/1.0
-(2021-09-03T04:29:42.1791523Z, 2021-09-03T04:29:43.1875033Z] tag1:value1tag2:value2 LongSum
-Value: 620
+Export MyFruitCounter, Meter: MyCompany.MyProduct.MyLibrary/1.0
+2021-09-23T03:17:30.6198292Z, 2021-09-23T03:17:30.6356517Z] color:redname:apple LongSum
+Value: 6
+2021-09-23T03:17:30.6198292Z, 2021-09-23T03:17:30.6356517Z] color:yellowname:lemon LongSum
+Value: 7
+2021-09-23T03:17:30.6198292Z, 2021-09-23T03:17:30.6356517Z] color:greenname:apple LongSum
+Value: 2
 ```
 <!-- markdownlint-enable MD013 -->
 
@@ -66,12 +50,10 @@ The program creates a
 [Meter](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#meter)
 instance named "MyCompany.MyProduct.MyLibrary" and then creates a
 [Counter](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#counter)
-instrument from it. This counter is used to repeatedly report metric
-measurements until it reaches a certain number of loops.
+instrument from it. This counter is used to report several metric measurements.
 
 An OpenTelemetry
 [MeterProvider](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#meterprovider)
 is configured to subscribe to instruments from the Meter
 `MyCompany.MyProduct.MyLibrary`, and aggregate the measurements in-memory. The
-pre-aggregated metrics are exported every 1 second to a `ConsoleExporter`.
-`ConsoleExporter` simply displays it on the console.
+pre-aggregated metrics are exported to a `ConsoleExporter`.

src/OpenTelemetry/Metrics/BaseExportingMetricReader.cs

@@ -15,6 +15,8 @@
 // </copyright>
 
 using System;
+using System.Diagnostics;
+using System.Threading;
 
 namespace OpenTelemetry.Metrics
 {
@@ -97,7 +99,22 @@ protected override bool OnCollect(int timeoutMilliseconds)
         /// <inheritdoc />
         protected override bool OnShutdown(int timeoutMilliseconds)
         {
-            return this.exporter.Shutdown(timeoutMilliseconds);
+            var result = true;
+
+            if (timeoutMilliseconds == Timeout.Infinite)
+            {
+                result = this.Collect(Timeout.Infinite) && result;
+                result = this.exporter.Shutdown(Timeout.Infinite) && result;
+            }
+            else
+            {
+                var sw = Stopwatch.StartNew();
+                result = this.Collect(timeoutMilliseconds) && result;
+                var timeout = timeoutMilliseconds - sw.ElapsedMilliseconds;
+                result = this.exporter.Shutdown((int)Math.Max(timeout, 0)) && result;
+            }
+
+            return result;
         }
 
         /// <inheritdoc/>

src/OpenTelemetry/Metrics/MetricReader.cs

@@ -211,7 +211,7 @@ protected virtual bool OnCollect(int timeoutMilliseconds)
         /// </remarks>
         protected virtual bool OnShutdown(int timeoutMilliseconds)
         {
-            return true;
+            return this.Collect(timeoutMilliseconds);
         }
 
         /// <summary>

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

@@ -84,9 +84,6 @@ void ProcessExport(Batch<Metric> batch)
             // giving some breezing room for the End callback to complete
             await Task.Delay(TimeSpan.FromSeconds(1));
 
-            // Invokes the TestExporter which will invoke ProcessExport
-            metricReader.Collect();
-
             this.meterProvider.Dispose();
 
             var requestMetrics = metricItems

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

@@ -112,9 +112,6 @@ void ProcessExport(Batch<Metric> batch)
                 }
             }
 
-            // Invokes the TestExporter which will invoke ProcessExport
-            metricReader.Collect();
-
             meterProvider.Dispose();
 
             var requestMetrics = metricItems