From 2dfc3ed4650285d3a848baffd1a571d9080097bc Mon Sep 17 00:00:00 2001
From: Andrew Kent <andrew.kent@datadoghq.com>
Date: Thu, 13 Dec 2018 08:17:19 -0800
Subject: [PATCH] Do not set the sampler rate for RateByServiceSampler

---
 .../datadog/trace/common/sampling/RateByServiceSampler.java    | 2 --
 .../src/test/groovy/datadog/opentracing/DDSpanTest.groovy      | 3 ---
 .../datadog/trace/api/sampling/RateByServiceSamplerTest.groovy | 3 ++-
 3 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/dd-trace-ot/src/main/java/datadog/trace/common/sampling/RateByServiceSampler.java b/dd-trace-ot/src/main/java/datadog/trace/common/sampling/RateByServiceSampler.java
index bad0b6f2f3..61e716efaa 100644
--- a/dd-trace-ot/src/main/java/datadog/trace/common/sampling/RateByServiceSampler.java
+++ b/dd-trace-ot/src/main/java/datadog/trace/common/sampling/RateByServiceSampler.java
@@ -2,7 +2,6 @@ package datadog.trace.common.sampling;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import datadog.opentracing.DDSpan;
-import datadog.opentracing.DDSpanContext;
 import datadog.trace.api.sampling.PrioritySampling;
 import datadog.trace.common.writer.DDApi.ResponseListener;
 import java.util.HashMap;
@@ -58,7 +57,6 @@ public class RateByServiceSampler implements Sampler, ResponseListener {
     } else {
       span.setSamplingPriority(PrioritySampling.SAMPLER_DROP);
     }
-    span.context().setMetric(DDSpanContext.SAMPLE_RATE_KEY, sampler.getSampleRate());
   }
 
   private static String getSpanEnv(DDSpan span) {
diff --git a/dd-trace-ot/src/test/groovy/datadog/opentracing/DDSpanTest.groovy b/dd-trace-ot/src/test/groovy/datadog/opentracing/DDSpanTest.groovy
index 3d2de7671b..548d4a0d5a 100644
--- a/dd-trace-ot/src/test/groovy/datadog/opentracing/DDSpanTest.groovy
+++ b/dd-trace-ot/src/test/groovy/datadog/opentracing/DDSpanTest.groovy
@@ -177,13 +177,10 @@ class DDSpanTest extends Specification {
     expect:
     parent.context().samplingPriority == PrioritySampling.SAMPLER_KEEP
     parent.getMetrics().get(DDSpanContext.PRIORITY_SAMPLING_KEY) == PrioritySampling.SAMPLER_KEEP
-    parent.getMetrics().get(DDSpanContext.SAMPLE_RATE_KEY) == 1.0
     child1.getSamplingPriority() == parent.getSamplingPriority()
     child1.getMetrics().get(DDSpanContext.PRIORITY_SAMPLING_KEY) == null
-    child1.getMetrics().get(DDSpanContext.SAMPLE_RATE_KEY) == null
     child2.getSamplingPriority() == parent.getSamplingPriority()
     child2.getMetrics().get(DDSpanContext.PRIORITY_SAMPLING_KEY) == null
-    child2.getMetrics().get(DDSpanContext.SAMPLE_RATE_KEY) == null
   }
 
   def "getRootSpan returns the root span"() {
diff --git a/dd-trace-ot/src/test/groovy/datadog/trace/api/sampling/RateByServiceSamplerTest.groovy b/dd-trace-ot/src/test/groovy/datadog/trace/api/sampling/RateByServiceSamplerTest.groovy
index 0b343b2997..dfa9faee30 100644
--- a/dd-trace-ot/src/test/groovy/datadog/trace/api/sampling/RateByServiceSamplerTest.groovy
+++ b/dd-trace-ot/src/test/groovy/datadog/trace/api/sampling/RateByServiceSamplerTest.groovy
@@ -65,6 +65,7 @@ class RateByServiceSamplerTest extends Specification {
     expect:
     // sets correctly on root span
     span.getSamplingPriority() == PrioritySampling.SAMPLER_KEEP
-    span.getMetrics().get("_sample_rate") == 1.0
+    // RateByServiceSamler must not set the sample rate
+    span.getMetrics().get("_sample_rate") == null
   }
 }