Merge pull request #1393 from DataDog/xgouchet/RUMM-3194/add_tracer_s…

…ampling_rate RUMM-3194 add tracer sampling rate
DataDog · Apr 18, 2023 · ef757a7 · ef757a7 · joshskeen · Apr 18, 2023
2 parents a3f9c38 + 2edc280
commit ef757a7
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Showing 7 changed files with 52 additions and 6 deletions.
diff --git a/buildSrc/src/main/kotlin/com/datadog/gradle/config/AndroidConfig.kt b/buildSrc/src/main/kotlin/com/datadog/gradle/config/AndroidConfig.kt
@@ -16,6 +16,7 @@ object AndroidConfig {
 
     // this is temporary, until we bump min sdk. Compose requires min sdk 21.
     const val MIN_SDK_FOR_COMPOSE = 21
+    const val MIN_SDK_FOR_WEAR = 23
     const val BUILD_TOOLS_VERSION = "33.0.0"
 
     val VERSION = Version(1, 19, 0, Version.Type.Snapshot)

diff --git a/dd-sdk-android/apiSurface b/dd-sdk-android/apiSurface
@@ -461,6 +461,7 @@ class com.datadog.android.tracing.AndroidTracer : com.datadog.opentracing.DDTrac
     fun setPartialFlushThreshold(Int): Builder
     fun addGlobalTag(String, String): Builder
     fun setBundleWithRumEnabled(Boolean): Builder
+    fun setSamplingRate(Double): Builder
   companion object 
     fun logThrowable(io.opentracing.Span, Throwable)
     fun logErrorMessage(io.opentracing.Span, String)

diff --git a/dd-sdk-android/src/main/java/com/datadog/trace/common/sampling/RateByServiceSampler.java b/dd-sdk-android/src/main/java/com/datadog/trace/common/sampling/RateByServiceSampler.java
@@ -26,8 +26,15 @@ public class RateByServiceSampler implements Sampler, PrioritySampler {
 
   private static final double DEFAULT_RATE = 1.0;
 
-  private volatile Map<String, RateSampler> serviceRates =
-      unmodifiableMap(singletonMap(DEFAULT_KEY, createRateSampler(DEFAULT_RATE)));
+  private volatile Map<String, RateSampler> serviceRates;
+
+  public RateByServiceSampler() {
+    this(DEFAULT_RATE);
+  }
+
+  public RateByServiceSampler(Double defaultSampleRate) {
+      this.serviceRates = singletonMap(DEFAULT_KEY, createRateSampler(defaultSampleRate));
+  }
 
   @Override
   public boolean sample(final DDSpan span) {
@@ -68,7 +75,6 @@ private static String getSpanEnv(final DDSpan span) {
     return null == span.getTags().get("env") ? "" : String.valueOf(span.getTags().get("env"));
   }
 
-
   private RateSampler createRateSampler(final double sampleRate) {
     final double sanitizedRate;
     if (sampleRate < 0) {

diff --git a/dd-sdk-android/src/main/java/com/datadog/trace/common/sampling/Sampler.java b/dd-sdk-android/src/main/java/com/datadog/trace/common/sampling/Sampler.java
@@ -26,9 +26,8 @@ final class Builder {
     public static Sampler forConfig(final Config config) {
       Sampler sampler;
       if (config != null) {
-
         if (config.isPrioritySamplingEnabled()) {
-          sampler = new RateByServiceSampler();
+          sampler = new RateByServiceSampler(config.getTraceSampleRate());
         } else {
           sampler = new AllSampler();
         }

diff --git a/dd-sdk-android/src/main/kotlin/com/datadog/android/tracing/AndroidTracer.kt b/dd-sdk-android/src/main/kotlin/com/datadog/android/tracing/AndroidTracer.kt
@@ -6,6 +6,7 @@
 
 package com.datadog.android.tracing
 
+import androidx.annotation.FloatRange
 import com.datadog.android.Datadog
 import com.datadog.android.core.internal.utils.internalLogger
 import com.datadog.android.log.LogAttributes
@@ -92,6 +93,7 @@ class AndroidTracer internal constructor(
 
         private var tracingHeaderTypes: Set<TracingHeaderType> = setOf(TracingHeaderType.DATADOG)
         private var bundleWithRumEnabled: Boolean = true
+        private var samplingRate: Double = DEFAULT_SAMPLING_RATE
 
         // TODO RUMM-0000 should have a nicer call chain
         private var serviceName: String? = (Datadog.globalSdkCore as? DatadogCore)
@@ -193,6 +195,17 @@ class AndroidTracer internal constructor(
             return this
         }
 
+        /**
+         * Sets the sampling rate of spans.
+         * @param samplingRate the sampling rate as a percentage between 0 and 100 (default is 100%)
+         */
+        fun setSamplingRate(
+            @FloatRange(from = 0.0, to = 100.0) samplingRate: Double
+        ): Builder {
+            this.samplingRate = samplingRate
+            return this
+        }
+
         // endregion
 
         // region Internal
@@ -216,6 +229,10 @@ class AndroidTracer internal constructor(
                 Config.TAGS,
                 globalTags.map { "${it.key}:${it.value}" }.joinToString(",")
             )
+            properties.setProperty(
+                Config.TRACE_SAMPLE_RATE,
+                (samplingRate / DEFAULT_SAMPLING_RATE).toString()
+            )
 
             val propagationStyles = tracingHeaderTypes.joinToString(",")
             properties.setProperty(Config.PROPAGATION_STYLE_EXTRACT, propagationStyles)
@@ -248,6 +265,8 @@ class AndroidTracer internal constructor(
     // endregion
 
     companion object {
+        internal const val DEFAULT_SAMPLING_RATE = 100.0
+
         internal const val TRACING_NOT_ENABLED_ERROR_MESSAGE =
             "You're trying to create an AndroidTracer instance, " +
                 "but either the SDK was not initialized or the Tracing feature was " +

diff --git a/dd-sdk-android/src/test/kotlin/com/datadog/android/tracing/internal/AndroidTracerTest.kt b/dd-sdk-android/src/test/kotlin/com/datadog/android/tracing/internal/AndroidTracerTest.kt
@@ -38,6 +38,7 @@ import com.nhaarman.mockitokotlin2.mock
 import com.nhaarman.mockitokotlin2.verify
 import com.nhaarman.mockitokotlin2.whenever
 import fr.xgouchet.elmyr.Forge
+import fr.xgouchet.elmyr.annotation.DoubleForgery
 import fr.xgouchet.elmyr.annotation.Forgery
 import fr.xgouchet.elmyr.annotation.LongForgery
 import fr.xgouchet.elmyr.annotation.StringForgery
@@ -48,6 +49,7 @@ import io.opentracing.Span
 import io.opentracing.log.Fields
 import io.opentracing.util.GlobalTracer
 import org.assertj.core.api.Assertions.assertThat
+import org.assertj.core.api.Assertions.offset
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
@@ -442,6 +444,24 @@ internal class AndroidTracerTest {
             .isEqualTo(threshold)
     }
 
+    @Test
+    fun `it will build a valid Tracer with sampling rate`(
+        @DoubleForgery(0.0, 1.0) samplingRate: Double
+    ) {
+        // Given
+
+        // When
+        val tracer = testedTracerBuilder
+            .setSamplingRate(samplingRate * 100.0)
+            .build()
+        val properties = testedTracerBuilder.properties()
+
+        // Then
+        assertThat(tracer).isNotNull()
+        assertThat(properties.getProperty(Config.TRACE_SAMPLE_RATE).toDouble())
+            .isCloseTo(samplingRate, offset(0.005))
+    }
+
     @Test
     fun `it will build a valid Tracer with global tags`(
         @StringForgery operation: String,

diff --git a/sample/wear/build.gradle.kts b/sample/wear/build.gradle.kts
@@ -18,7 +18,7 @@ android {
 
     defaultConfig {
         applicationId = "com.datadog.android.wear.sample"
-        minSdk = AndroidConfig.MIN_SDK_FOR_COMPOSE
+        minSdk = AndroidConfig.MIN_SDK_FOR_WEAR
         targetSdk = AndroidConfig.TARGET_SDK
         versionCode = AndroidConfig.VERSION.code
         versionName = AndroidConfig.VERSION.name