[AzureMonitor] Change drop sampling result to recordOnly

src/OpenTelemetry.Extensions.AzureMonitor/ApplicationInsightsSampler.cs

@@ -26,7 +26,7 @@ namespace OpenTelemetry.Extensions.AzureMonitor;
 /// </summary>
 public class ApplicationInsightsSampler : Sampler
 {
-    private static readonly SamplingResult DropSamplingResult = new(false);
+    private static readonly SamplingResult RecordOnlySamplingResult = new(SamplingDecision.RecordOnly);
     private readonly SamplingResult recordAndSampleSamplingResult;
     private readonly float samplingRatio;
 
@@ -63,7 +63,7 @@ public override SamplingResult ShouldSample(in SamplingParameters samplingParame
     {
         if (this.samplingRatio == 0)
         {
-            return DropSamplingResult;
+            return RecordOnlySamplingResult;
         }
 
         if (this.samplingRatio == 1)
@@ -79,7 +79,7 @@ public override SamplingResult ShouldSample(in SamplingParameters samplingParame
         }
         else
         {
-            return DropSamplingResult;
+            return RecordOnlySamplingResult;
         }
     }
 

src/OpenTelemetry.Extensions.AzureMonitor/CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+* Sampler will now return `RecordOnly` SamplingResult when the telemetry is
+sampled out.
+([#933](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/933))
+
 ## 1.0.0-beta.2
 
 Released 2022-Sept-12

test/OpenTelemetry.Extensions.AzureMonitor.Tests/ApplicationInsightsSamplerTests.cs

@@ -50,8 +50,8 @@ public void VerifyHashAlgorithmCorrectness()
 
         // Verify sample ratio: 0
         ApplicationInsightsSampler zeroSampler = new ApplicationInsightsSampler(samplingRatio: 0);
-        Assert.Equal(SamplingDecision.Drop, zeroSampler.ShouldSample(testParams1).Decision);
-        Assert.Equal(SamplingDecision.Drop, zeroSampler.ShouldSample(testParams2).Decision);
+        Assert.Equal(SamplingDecision.RecordOnly, zeroSampler.ShouldSample(testParams1).Decision);
+        Assert.Equal(SamplingDecision.RecordOnly, zeroSampler.ShouldSample(testParams2).Decision);
 
         // Verify sample ratio: 1
         ApplicationInsightsSampler oneSampler = new ApplicationInsightsSampler(samplingRatio: 1);
@@ -61,7 +61,7 @@ public void VerifyHashAlgorithmCorrectness()
         // Verify sample ratio: 0.5.
         // This is below the sample score for testId2, but strict enough to drop testId1
         ApplicationInsightsSampler ratioSampler = new ApplicationInsightsSampler(samplingRatio: 0.5f);
-        Assert.Equal(SamplingDecision.Drop, ratioSampler.ShouldSample(testParams1).Decision);
+        Assert.Equal(SamplingDecision.RecordOnly, ratioSampler.ShouldSample(testParams1).Decision);
         Assert.Equal(SamplingDecision.RecordAndSample, ratioSampler.ShouldSample(testParams2).Decision);
     }