[Sampler.AWS] Wrapped root sampler with ParentBasedSampler (open-telemetry#2188)

Co-authored-by: Piotr Kiełkowicz <[email protected]>

Author: AsakerMohd

src/OpenTelemetry.Sampler.AWS/.publicApi/PublicAPI.Unshipped.txt

@@ -2,7 +2,7 @@
 OpenTelemetry.Sampler.AWS.AWSXRayRemoteSampler
 OpenTelemetry.Sampler.AWS.AWSXRayRemoteSampler.Dispose() -> void
 OpenTelemetry.Sampler.AWS.AWSXRayRemoteSamplerBuilder
-OpenTelemetry.Sampler.AWS.AWSXRayRemoteSamplerBuilder.Build() -> OpenTelemetry.Sampler.AWS.AWSXRayRemoteSampler!
+OpenTelemetry.Sampler.AWS.AWSXRayRemoteSamplerBuilder.Build() -> OpenTelemetry.Trace.Sampler!
 OpenTelemetry.Sampler.AWS.AWSXRayRemoteSamplerBuilder.SetEndpoint(string! endpoint) -> OpenTelemetry.Sampler.AWS.AWSXRayRemoteSamplerBuilder!
 OpenTelemetry.Sampler.AWS.AWSXRayRemoteSamplerBuilder.SetPollingInterval(System.TimeSpan pollingInterval) -> OpenTelemetry.Sampler.AWS.AWSXRayRemoteSamplerBuilder!
 override OpenTelemetry.Sampler.AWS.AWSXRayRemoteSampler.ShouldSample(in OpenTelemetry.Trace.SamplingParameters samplingParameters) -> OpenTelemetry.Trace.SamplingResult

src/OpenTelemetry.Sampler.AWS/AWSXRayRemoteSamplerBuilder.cs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 using OpenTelemetry.Resources;
+using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Sampler.AWS;
 
@@ -66,10 +67,11 @@ public AWSXRayRemoteSamplerBuilder SetEndpoint(string endpoint)
     /// <summary>
     /// Returns a <see cref="AWSXRayRemoteSampler"/> with configuration of this builder.
     /// </summary>
-    /// <returns>an instance of <see cref="AWSXRayRemoteSampler"/>.</returns>
-    public AWSXRayRemoteSampler Build()
+    /// <returns>an instance of <see cref="Trace.Sampler"/>.</returns>
+    public Trace.Sampler Build()
     {
-        return new AWSXRayRemoteSampler(this.resource, this.pollingInterval, this.endpoint, this.clock);
+        var rootSampler = new AWSXRayRemoteSampler(this.resource, this.pollingInterval, this.endpoint, this.clock);
+        return new ParentBasedSampler(rootSampler);
     }
 
     // This is intended for testing with a mock clock.

src/OpenTelemetry.Sampler.AWS/CHANGELOG.md

@@ -17,6 +17,10 @@
 * Updated OpenTelemetry core component version(s) to `1.10.0`.
   ([#2317](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2317))
 
+* `AWSXRayRemoteSamplerBuilder.Build()` now returns `ParentBasedSampler` which
+  which is of type `Sampler` instead of `AWSXRayRemoteSampler`.
+  ([#2188](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2188))
+
 ## 0.1.0-alpha.2
 
 Released 2024-Sep-09

src/OpenTelemetry.Sampler.AWS/FallbackSampler.cs

@@ -12,8 +12,8 @@ internal class FallbackSampler : Trace.Sampler
 
     public FallbackSampler(Clock clock)
     {
-        this.reservoirSampler = new ParentBasedSampler(new RateLimitingSampler(1, clock));
-        this.fixedRateSampler = new ParentBasedSampler(new TraceIdRatioBasedSampler(0.05));
+        this.reservoirSampler = new RateLimitingSampler(1, clock);
+        this.fixedRateSampler = new TraceIdRatioBasedSampler(0.05);
     }
 
     public override SamplingResult ShouldSample(in SamplingParameters samplingParameters)

src/OpenTelemetry.Sampler.AWS/SamplingRuleApplier.cs

@@ -20,7 +20,7 @@ public SamplingRuleApplier(string clientId, Clock clock, SamplingRule rule, Stat
         {
             // Until calling GetSamplingTargets, the default is to borrow 1/s if reservoir size is
             // positive.
-            this.ReservoirSampler = new ParentBasedSampler(new RateLimitingSampler(1, this.Clock));
+            this.ReservoirSampler = new RateLimitingSampler(1, this.Clock);
             this.Borrowing = true;
         }
         else
@@ -30,7 +30,7 @@ public SamplingRuleApplier(string clientId, Clock clock, SamplingRule rule, Stat
             this.Borrowing = false;
         }
 
-        this.FixedRateSampler = new ParentBasedSampler(new TraceIdRatioBasedSampler(rule.FixedRate));
+        this.FixedRateSampler = new TraceIdRatioBasedSampler(rule.FixedRate);
 
         // We either have no reservoir sampling or borrow until we get a quota so have no end time.
         this.ReservoirEndTime = DateTimeOffset.MaxValue;
@@ -191,15 +191,15 @@ public SamplingStatisticsDocument Snapshot(DateTimeOffset now)
     public SamplingRuleApplier WithTarget(SamplingTargetDocument target, DateTimeOffset now)
     {
         var newFixedRateSampler = target.FixedRate != null
-            ? new ParentBasedSampler(new TraceIdRatioBasedSampler(target.FixedRate.Value))
+            ? new TraceIdRatioBasedSampler(target.FixedRate.Value)
             : this.FixedRateSampler;
 
         Trace.Sampler newReservoirSampler = new AlwaysOffSampler();
         var newReservoirEndTime = DateTimeOffset.MaxValue;
         if (target.ReservoirQuota != null && target.ReservoirQuotaTTL != null)
         {
             newReservoirSampler = target.ReservoirQuota > 0
-                ? new ParentBasedSampler(new RateLimitingSampler(target.ReservoirQuota.Value, this.Clock))
+                ? new RateLimitingSampler(target.ReservoirQuota.Value, this.Clock)
                 : new AlwaysOffSampler();
 
             newReservoirEndTime = this.Clock.ToDateTime(target.ReservoirQuotaTTL.Value);

test/OpenTelemetry.Sampler.AWS.Tests/TestAWSXRayRemoteSampler.cs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 using System.Diagnostics;
+using System.Reflection;
 using OpenTelemetry.Resources;
 using OpenTelemetry.Trace;
 using WireMock.RequestBuilders;
@@ -18,27 +19,34 @@ public void TestSamplerWithConfiguration()
     {
         var pollingInterval = TimeSpan.FromSeconds(5);
         var endpoint = "http://localhost:3000";
-
-        var sampler = AWSXRayRemoteSampler.Builder(ResourceBuilder.CreateEmpty().Build())
+        var parentBasedSampler = AWSXRayRemoteSampler.Builder(ResourceBuilder.CreateEmpty().Build())
             .SetPollingInterval(pollingInterval)
             .SetEndpoint(endpoint)
             .Build();
 
-        Assert.Equal(pollingInterval, sampler.PollingInterval);
-        Assert.Equal(endpoint, sampler.Endpoint);
-        Assert.NotNull(sampler.RulePollerTimer);
-        Assert.NotNull(sampler.Client);
+        FieldInfo? rootSamplerFieldInfo = typeof(ParentBasedSampler).GetField("rootSampler", BindingFlags.NonPublic | BindingFlags.Instance);
+
+        var xraySampler = (AWSXRayRemoteSampler?)rootSamplerFieldInfo?.GetValue(parentBasedSampler);
+
+        Assert.Equal(pollingInterval, xraySampler?.PollingInterval);
+        Assert.Equal(endpoint, xraySampler?.Endpoint);
+        Assert.NotNull(xraySampler?.RulePollerTimer);
+        Assert.NotNull(xraySampler?.Client);
     }
 
     [Fact]
     public void TestSamplerWithDefaults()
     {
-        var sampler = AWSXRayRemoteSampler.Builder(ResourceBuilder.CreateEmpty().Build()).Build();
+        var parentBasedSampler = AWSXRayRemoteSampler.Builder(ResourceBuilder.CreateEmpty().Build()).Build();
+
+        FieldInfo? rootSamplerFieldInfo = typeof(ParentBasedSampler).GetField("rootSampler", BindingFlags.NonPublic | BindingFlags.Instance);
+
+        var xraySampler = (AWSXRayRemoteSampler?)rootSamplerFieldInfo?.GetValue(parentBasedSampler);
 
-        Assert.Equal(TimeSpan.FromMinutes(5), sampler.PollingInterval);
-        Assert.Equal("http://localhost:2000", sampler.Endpoint);
-        Assert.NotNull(sampler.RulePollerTimer);
-        Assert.NotNull(sampler.Client);
+        Assert.Equal(TimeSpan.FromMinutes(5), xraySampler?.PollingInterval);
+        Assert.Equal("http://localhost:2000", xraySampler?.Endpoint);
+        Assert.NotNull(xraySampler?.RulePollerTimer);
+        Assert.NotNull(xraySampler?.Client);
     }
 
     [Fact(Skip = "Flaky test. Related issue: https://github.com/open-telemetry/opentelemetry-dotnet-contrib/issues/1219")]