Initial ideal how to refactor provider (#1008)

* initial ideal how to refactor provider

* dumping more ideas

* more improvements

* update example

* improve perf when no sampler is specified

* put more examples

* composite processor

* update the tutorial

* more check

* nit

* update tutorial

docs/trace/building-your-own-exporter/Program.cs

@@ -25,14 +25,18 @@ public class Program
 
     public static void Main()
     {
-        using var otel = Sdk.CreateTracerProvider(b => b
-            .AddActivitySource("MyCompany.MyProduct.MyLibrary")
-            .UseMyExporter());
+        using var tracerProvider = Sdk.CreateTracerProvider(
+            new string[]
+            {
+                "MyCompany.MyProduct.MyLibrary",
+            })
+            .AddMyExporter();
 
         using (var activity = MyActivitySource.StartActivity("SayHello"))
         {
             activity?.SetTag("foo", 1);
             activity?.SetTag("bar", "Hello, World!");
+            activity?.SetTag("baz", new int[] { 1, 2, 3 });
         }
     }
 }

docs/trace/building-your-own-exporter/TracerProviderBuilderExtensions.cs → docs/trace/building-your-own-exporter/TracerProviderExtensions.cs

@@ -1,4 +1,4 @@
-// <copyright file="TracerProviderBuilderExtensions.cs" company="OpenTelemetry Authors">
+// <copyright file="TracerProviderExtensions.cs" company="OpenTelemetry Authors">
 // Copyright The OpenTelemetry Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -17,15 +17,10 @@
 using System;
 using OpenTelemetry.Trace;
 
-internal static class TracerProviderBuilderExtensions
+internal static class TracerProviderExtensions
 {
-    public static TracerProviderBuilder UseMyExporter(this TracerProviderBuilder builder)
+    public static TracerProvider AddMyExporter(this TracerProvider provider)
     {
-        if (builder == null)
-        {
-            throw new ArgumentNullException(nameof(builder));
-        }
-
-        return builder.AddProcessorPipeline(p => p.SetExporter(new MyExporter()));
+        return provider?.AddProcessor(new SimpleActivityProcessor(new MyExporter()));
     }
 }

docs/trace/building-your-own-processor/Program.cs

@@ -25,20 +25,19 @@ public class Program
 
     public static void Main()
     {
-        using var otel = Sdk.CreateTracerProvider(b => b
-            .AddActivitySource("MyCompany.MyProduct.MyLibrary")
+        using var tracerProvider = Sdk.CreateTracerProvider(
+            new string[]
+            {
+                "MyCompany.MyProduct.MyLibrary",
+            })
+            .AddProcessor(new MyActivityProcessor("A"))
+            .AddProcessor(new MyActivityProcessor("B"));
 
-            // TODO: seems buggy as ShutdownAsync is called 6 times
-            // TODO: need to discuss the expectation, currently FlushAsync is not called by default
-            // TODO: should the dispose order be C, B, A or A, B C?
-            .AddProcessorPipeline(p => p.AddProcessor(current => new MyActivityProcessor("A")))
-            .AddProcessorPipeline(p => p.AddProcessor(current => new MyActivityProcessor("B")))
-            .AddProcessorPipeline(p => p.AddProcessor(current => new MyActivityProcessor("C"))));
-
-        using (var activity = MyActivitySource.StartActivity("SayHello"))
+        using (var activity = MyActivitySource.StartActivity("Foo"))
         {
             activity?.SetTag("foo", 1);
             activity?.SetTag("bar", "Hello, World!");
+            activity?.SetTag("baz", new int[] { 1, 2, 3 });
         }
     }
 }

docs/trace/building-your-own-sampler/Program.cs

@@ -16,6 +16,7 @@
 
 using System.Diagnostics;
 using OpenTelemetry;
+using OpenTelemetry.Exporter.Console;
 using OpenTelemetry.Trace;
 
 public class Program
@@ -25,10 +26,13 @@ public class Program
 
     public static void Main()
     {
-        using var otel = Sdk.CreateTracerProvider(b => b
-            .AddActivitySource("MyCompany.MyProduct.MyLibrary")
-            .SetSampler(new MySampler()) // TODO: it is NOT working at this moment
-            .UseConsoleExporter());
+        using var tracerProvider = Sdk.CreateTracerProvider(
+            new string[]
+            {
+                "MyCompany.MyProduct.MyLibrary",
+            },
+            new MySampler())
+            .AddProcessor(new SimpleActivityProcessor(new ConsoleExporter(new ConsoleExporterOptions())));
 
         using (var activity = MyActivitySource.StartActivity("SayHello"))
         {

docs/trace/getting-started/Program.cs

@@ -16,6 +16,7 @@
 
 using System.Diagnostics;
 using OpenTelemetry;
+using OpenTelemetry.Exporter.Console;
 using OpenTelemetry.Trace;
 
 public class Program
@@ -25,9 +26,13 @@ public class Program
 
     public static void Main()
     {
-        using var otel = Sdk.CreateTracerProvider(b => b
-            .AddActivitySource("MyCompany.MyProduct.MyLibrary")
-            .UseConsoleExporter());
+        using var tracerProvider = Sdk.CreateTracerProvider(
+            new string[]
+            {
+                "MyCompany.MyProduct.MyLibrary",
+            });
+
+        tracerProvider.AddProcessor(new SimpleActivityProcessor(new ConsoleExporter(new ConsoleExporterOptions())));
 
         using (var activity = MyActivitySource.StartActivity("SayHello"))
         {

src/OpenTelemetry/Sdk.cs

@@ -13,6 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 // </copyright>
+
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -22,6 +23,7 @@
 using OpenTelemetry.Context;
 using OpenTelemetry.Metrics;
 using OpenTelemetry.Metrics.Export;
+using OpenTelemetry.Resources;
 using OpenTelemetry.Trace;
 using OpenTelemetry.Trace.Internal;
 using OpenTelemetry.Trace.Samplers;
@@ -161,30 +163,85 @@ public static TracerProvider CreateTracerProvider(Action<TracerProviderBuilder>
             return tracerProviderSdk;
         }
 
+        public static TracerProvider CreateTracerProvider(IEnumerable<string> sources, Sampler sampler = null, Resource resource = null)
+        {
+            var activitySources = new Dictionary<string, bool>(StringComparer.OrdinalIgnoreCase);
+
+            foreach (var name in sources)
+            {
+                activitySources[name] = true;
+            }
+
+            var provider = new TracerProviderSdk
+            {
+                Resource = resource,
+                Sampler = sampler,
+            };
+
+            provider.ActivityListener = new ActivityListener
+            {
+                // Callback when Activity is started.
+                ActivityStarted = (activity) =>
+                {
+                    if (activity.IsAllDataRequested)
+                    {
+                        activity.SetResource(resource);
+                    }
+
+                    provider.ActivityProcessor?.OnStart(activity);
+                },
+
+                // Callback when Activity is stopped.
+                ActivityStopped = (activity) =>
+                {
+                    provider.ActivityProcessor?.OnEnd(activity);
+                },
+
+                // Function which takes ActivitySource and returns true/false to indicate if it should be subscribed to
+                // or not.
+                ShouldListenTo = (activitySource) => activitySources.ContainsKey(activitySource.Name),
+
+                // Setting this to true means TraceId will be always
+                // available in sampling callbacks and will be the actual
+                // traceid used, if activity ends up getting created.
+                AutoGenerateRootContextTraceId = true,
+
+                // This delegate informs ActivitySource about sampling decision when the parent context is an ActivityContext.
+                GetRequestedDataUsingContext = (ref ActivityCreationOptions<ActivityContext> options) => ComputeActivityDataRequest(options, sampler),
+            };
+
+            ActivitySource.AddActivityListener(provider.ActivityListener);
+
+            return provider;
+        }
+
         internal static ActivityDataRequest ComputeActivityDataRequest(
             in ActivityCreationOptions<ActivityContext> options,
             Sampler sampler)
         {
             var isRootSpan = /*TODO: Put back once AutoGenerateRootContextTraceId is removed.
                               options.Parent.TraceId == default ||*/ options.Parent.SpanId == default;
 
-            // As we set ActivityListener.AutoGenerateRootContextTraceId = true,
-            // Parent.TraceId will always be the TraceId of the to-be-created Activity,
-            // if it get created.
-            ActivityTraceId traceId = options.Parent.TraceId;
-
-            var samplingParameters = new SamplingParameters(
-                options.Parent,
-                traceId,
-                options.Name,
-                options.Kind,
-                options.Tags,
-                options.Links);
-
-            var shouldSample = sampler.ShouldSample(samplingParameters);
-            if (shouldSample.IsSampled)
+            if (sampler != null)
             {
-                return ActivityDataRequest.AllDataAndRecorded;
+                // As we set ActivityListener.AutoGenerateRootContextTraceId = true,
+                // Parent.TraceId will always be the TraceId of the to-be-created Activity,
+                // if it get created.
+                ActivityTraceId traceId = options.Parent.TraceId;
+
+                var samplingParameters = new SamplingParameters(
+                    options.Parent,
+                    traceId,
+                    options.Name,
+                    options.Kind,
+                    options.Tags,
+                    options.Links);
+
+                var shouldSample = sampler.ShouldSample(samplingParameters);
+                if (shouldSample.IsSampled)
+                {
+                    return ActivityDataRequest.AllDataAndRecorded;
+                }
             }
 
             // If it is the root span select PropagationData so the trace ID is preserved