From 231abe6e0d33b9d080f61ef20c4abb1cb543e2e2 Mon Sep 17 00:00:00 2001 From: "opensearch-trigger-bot[bot]" <98922864+opensearch-trigger-bot[bot]@users.noreply.github.com> Date: Thu, 31 Aug 2023 13:49:49 -0400 Subject: [PATCH] Added sampler based on Blanket Probabilistic Sampling rate and Override for on demand (#9522) (#9668) (cherry picked from commit 082d425c21a77185f1ce303998ab343e3ce475c4) Signed-off-by: Dev Agarwal Signed-off-by: github-actions[bot] Co-authored-by: github-actions[bot] --- CHANGELOG.md | 1 + .../IntegrationTestOTelTelemetryPlugin.java | 6 +- .../telemetry/OTelTelemetryPlugin.java | 8 +- .../tracing/OTelResourceProvider.java | 8 +- .../tracing/sampler/ProbabilisticSampler.java | 82 +++++++++++++++++ .../tracing/sampler/RequestSampler.java | 67 ++++++++++++++ .../tracing/sampler/package-info.java | 12 +++ .../telemetry/OTelTelemetryPluginTests.java | 6 +- .../sampler/ProbabilisticSamplerTests.java | 64 +++++++++++++ .../tracing/sampler/RequestSamplerTests.java | 92 +++++++++++++++++++ .../common/settings/ClusterSettings.java | 2 +- .../opensearch/plugins/TelemetryPlugin.java | 2 +- .../telemetry/TelemetrySettings.java | 29 ++++++ 13 files changed, 367 insertions(+), 12 deletions(-) create mode 100644 plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSampler.java create mode 100644 plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/RequestSampler.java create mode 100644 plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/package-info.java create mode 100644 plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSamplerTests.java create mode 100644 plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/RequestSamplerTests.java diff --git a/CHANGELOG.md b/CHANGELOG.md index e8a0e84953b10..649cbca447b95 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -96,6 +96,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), - Add support to use trace propagated from client ([#9506](https://github.com/opensearch-project/OpenSearch/pull/9506)) - Separate request-based and settings-based concurrent segment search controls and introduce AggregatorFactory method to determine concurrent search support ([#9469](https://github.com/opensearch-project/OpenSearch/pull/9469)) - Use non-concurrent path for sort request on timeseries index and field([#9562](https://github.com/opensearch-project/OpenSearch/pull/9562)) +- Added sampler based on `Blanket Probabilistic Sampling rate` and `Override for on demand` ([#9621](https://github.com/opensearch-project/OpenSearch/issues/9621)) ### Deprecated diff --git a/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/IntegrationTestOTelTelemetryPlugin.java b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/IntegrationTestOTelTelemetryPlugin.java index 57dbf4e001be4..ed4d13f3abb7d 100644 --- a/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/IntegrationTestOTelTelemetryPlugin.java +++ b/plugins/telemetry-otel/src/internalClusterTest/java/org/opensearch/telemetry/tracing/IntegrationTestOTelTelemetryPlugin.java @@ -32,10 +32,10 @@ public IntegrationTestOTelTelemetryPlugin(Settings settings) { /** * This method overrides getTelemetry() method in OTel plugin class, so we create only one instance of global OpenTelemetry * resetForTest() will set OpenTelemetry to null again. - * @param settings cluster settings + * @param telemetrySettings telemetry settings */ - public Optional getTelemetry(TelemetrySettings settings) { + public Optional getTelemetry(TelemetrySettings telemetrySettings) { GlobalOpenTelemetry.resetForTest(); - return super.getTelemetry(settings); + return super.getTelemetry(telemetrySettings); } } diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetryPlugin.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetryPlugin.java index a1ca3adf4d2a2..1af88196e3727 100644 --- a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetryPlugin.java +++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/OTelTelemetryPlugin.java @@ -49,8 +49,8 @@ public List> getSettings() { } @Override - public Optional getTelemetry(TelemetrySettings settings) { - return Optional.of(telemetry()); + public Optional getTelemetry(TelemetrySettings telemetrySettings) { + return Optional.of(telemetry(telemetrySettings)); } @Override @@ -58,8 +58,8 @@ public String getName() { return OTEL_TRACER_NAME; } - private Telemetry telemetry() { - return new OTelTelemetry(new OTelTracingTelemetry(OTelResourceProvider.get(settings)), new MetricsTelemetry() { + private Telemetry telemetry(TelemetrySettings telemetrySettings) { + return new OTelTelemetry(new OTelTracingTelemetry(OTelResourceProvider.get(telemetrySettings, settings)), new MetricsTelemetry() { }); } diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelResourceProvider.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelResourceProvider.java index 1ec4818b8b73e..b395a335a4d83 100644 --- a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelResourceProvider.java +++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/OTelResourceProvider.java @@ -9,7 +9,10 @@ package org.opensearch.telemetry.tracing; import org.opensearch.common.settings.Settings; +import org.opensearch.telemetry.TelemetrySettings; import org.opensearch.telemetry.tracing.exporter.OTelSpanExporterFactory; +import org.opensearch.telemetry.tracing.sampler.ProbabilisticSampler; +import org.opensearch.telemetry.tracing.sampler.RequestSampler; import java.util.concurrent.TimeUnit; @@ -37,15 +40,16 @@ private OTelResourceProvider() {} /** * Creates OpenTelemetry instance with default configuration + * @param telemetrySettings telemetry settings * @param settings cluster settings * @return OpenTelemetry instance */ - public static OpenTelemetry get(Settings settings) { + public static OpenTelemetry get(TelemetrySettings telemetrySettings, Settings settings) { return get( settings, OTelSpanExporterFactory.create(settings), ContextPropagators.create(W3CTraceContextPropagator.getInstance()), - Sampler.alwaysOn() + Sampler.parentBased(new RequestSampler(new ProbabilisticSampler(telemetrySettings))) ); } diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSampler.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSampler.java new file mode 100644 index 0000000000000..cab7b1a4af2e6 --- /dev/null +++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSampler.java @@ -0,0 +1,82 @@ +/* + * SPDX-License-Identifier: Apache-2.0 + * + * The OpenSearch Contributors require contributions made to + * this file be licensed under the Apache-2.0 license or a + * compatible open source license. + */ + +package org.opensearch.telemetry.tracing.sampler; + +import org.opensearch.telemetry.TelemetrySettings; + +import java.util.List; +import java.util.Objects; + +import io.opentelemetry.api.common.Attributes; +import io.opentelemetry.api.trace.SpanKind; +import io.opentelemetry.context.Context; +import io.opentelemetry.sdk.trace.data.LinkData; +import io.opentelemetry.sdk.trace.samplers.Sampler; +import io.opentelemetry.sdk.trace.samplers.SamplingResult; + +/** + * ProbabilisticSampler implements a head-based sampling strategy based on provided settings. + */ +public class ProbabilisticSampler implements Sampler { + private Sampler defaultSampler; + private final TelemetrySettings telemetrySettings; + private double samplingRatio; + + /** + * Constructor + * + * @param telemetrySettings Telemetry settings. + */ + public ProbabilisticSampler(TelemetrySettings telemetrySettings) { + this.telemetrySettings = Objects.requireNonNull(telemetrySettings); + this.samplingRatio = telemetrySettings.getTracerHeadSamplerSamplingRatio(); + this.defaultSampler = Sampler.traceIdRatioBased(samplingRatio); + } + + Sampler getSampler() { + double newSamplingRatio = telemetrySettings.getTracerHeadSamplerSamplingRatio(); + if (isSamplingRatioChanged(newSamplingRatio)) { + synchronized (this) { + this.samplingRatio = newSamplingRatio; + defaultSampler = Sampler.traceIdRatioBased(samplingRatio); + } + } + return defaultSampler; + } + + private boolean isSamplingRatioChanged(double newSamplingRatio) { + return Double.compare(this.samplingRatio, newSamplingRatio) != 0; + } + + double getSamplingRatio() { + return samplingRatio; + } + + @Override + public SamplingResult shouldSample( + Context parentContext, + String traceId, + String name, + SpanKind spanKind, + Attributes attributes, + List parentLinks + ) { + return getSampler().shouldSample(parentContext, traceId, name, spanKind, attributes, parentLinks); + } + + @Override + public String getDescription() { + return "Probabilistic Sampler"; + } + + @Override + public String toString() { + return getDescription(); + } +} diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/RequestSampler.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/RequestSampler.java new file mode 100644 index 0000000000000..9ea681370a3ec --- /dev/null +++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/RequestSampler.java @@ -0,0 +1,67 @@ +/* + * SPDX-License-Identifier: Apache-2.0 + * + * The OpenSearch Contributors require contributions made to + * this file be licensed under the Apache-2.0 license or a + * compatible open source license. + */ + +package org.opensearch.telemetry.tracing.sampler; + +import java.util.List; + +import io.opentelemetry.api.common.AttributeKey; +import io.opentelemetry.api.common.Attributes; +import io.opentelemetry.api.trace.SpanKind; +import io.opentelemetry.context.Context; +import io.opentelemetry.sdk.trace.data.LinkData; +import io.opentelemetry.sdk.trace.samplers.Sampler; +import io.opentelemetry.sdk.trace.samplers.SamplingResult; + +/** + * HeadBased sampler + */ +public class RequestSampler implements Sampler { + private final Sampler defaultSampler; + + // TODO: Pick value of TRACE from PR #9415. + private static final String TRACE = "trace"; + + /** + * Creates Head based sampler + * @param defaultSampler defaultSampler + */ + public RequestSampler(Sampler defaultSampler) { + this.defaultSampler = defaultSampler; + } + + @Override + public SamplingResult shouldSample( + Context parentContext, + String traceId, + String name, + SpanKind spanKind, + Attributes attributes, + List parentLinks + ) { + + final String trace = attributes.get(AttributeKey.stringKey(TRACE)); + + if (trace != null) { + return (Boolean.parseBoolean(trace) == true) ? SamplingResult.recordAndSample() : SamplingResult.drop(); + } else { + return defaultSampler.shouldSample(parentContext, traceId, name, spanKind, attributes, parentLinks); + } + + } + + @Override + public String getDescription() { + return "Request Sampler"; + } + + @Override + public String toString() { + return getDescription(); + } +} diff --git a/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/package-info.java b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/package-info.java new file mode 100644 index 0000000000000..6534b33f6177c --- /dev/null +++ b/plugins/telemetry-otel/src/main/java/org/opensearch/telemetry/tracing/sampler/package-info.java @@ -0,0 +1,12 @@ +/* + * SPDX-License-Identifier: Apache-2.0 + * + * The OpenSearch Contributors require contributions made to + * this file be licensed under the Apache-2.0 license or a + * compatible open source license. + */ + +/** + * This package contains classes needed for sampler. + */ +package org.opensearch.telemetry.tracing.sampler; diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/OTelTelemetryPluginTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/OTelTelemetryPluginTests.java index 611656942860f..8c2b5d14733e2 100644 --- a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/OTelTelemetryPluginTests.java +++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/OTelTelemetryPluginTests.java @@ -29,6 +29,8 @@ import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_BATCH_SIZE_SETTING; import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_DELAY_SETTING; import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_MAX_QUEUE_SIZE_SETTING; +import static org.opensearch.telemetry.TelemetrySettings.TRACER_ENABLED_SETTING; +import static org.opensearch.telemetry.TelemetrySettings.TRACER_SAMPLER_PROBABILITY; public class OTelTelemetryPluginTests extends OpenSearchTestCase { @@ -42,7 +44,9 @@ public void setup() { // io.opentelemetry.sdk.OpenTelemetrySdk.close waits only for 10 seconds for shutdown to complete. Settings settings = Settings.builder().put(TRACER_EXPORTER_DELAY_SETTING.getKey(), "1s").build(); oTelTracerModulePlugin = new OTelTelemetryPlugin(settings); - telemetry = oTelTracerModulePlugin.getTelemetry(null); + telemetry = oTelTracerModulePlugin.getTelemetry( + new TelemetrySettings(Settings.EMPTY, new ClusterSettings(settings, Set.of(TRACER_ENABLED_SETTING, TRACER_SAMPLER_PROBABILITY))) + ); tracingTelemetry = telemetry.get().getTracingTelemetry(); } diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSamplerTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSamplerTests.java new file mode 100644 index 0000000000000..639dc341ef0db --- /dev/null +++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/ProbabilisticSamplerTests.java @@ -0,0 +1,64 @@ +/* + * SPDX-License-Identifier: Apache-2.0 + * + * The OpenSearch Contributors require contributions made to + * this file be licensed under the Apache-2.0 license or a + * compatible open source license. + */ + +package org.opensearch.telemetry.tracing.sampler; + +import org.opensearch.common.settings.ClusterSettings; +import org.opensearch.common.settings.Settings; +import org.opensearch.telemetry.TelemetrySettings; +import org.opensearch.test.OpenSearchTestCase; + +import java.util.Set; + +import io.opentelemetry.sdk.trace.samplers.Sampler; + +import static org.opensearch.telemetry.OTelTelemetrySettings.TRACER_EXPORTER_DELAY_SETTING; +import static org.opensearch.telemetry.TelemetrySettings.TRACER_ENABLED_SETTING; +import static org.opensearch.telemetry.TelemetrySettings.TRACER_SAMPLER_PROBABILITY; + +public class ProbabilisticSamplerTests extends OpenSearchTestCase { + + // When ProbabilisticSampler is created with OTelTelemetrySettings as null + public void testProbabilisticSamplerWithNullSettings() { + // Verify that the constructor throws IllegalArgumentException when given null settings + assertThrows(NullPointerException.class, () -> { new ProbabilisticSampler(null); }); + } + + public void testDefaultGetSampler() { + Settings settings = Settings.builder().put(TRACER_EXPORTER_DELAY_SETTING.getKey(), "1s").build(); + TelemetrySettings telemetrySettings = new TelemetrySettings( + Settings.EMPTY, + new ClusterSettings(settings, Set.of(TRACER_SAMPLER_PROBABILITY, TRACER_ENABLED_SETTING)) + ); + + // Probabilistic Sampler + ProbabilisticSampler probabilisticSampler = new ProbabilisticSampler(telemetrySettings); + + assertNotNull(probabilisticSampler.getSampler()); + assertEquals(0.01, probabilisticSampler.getSamplingRatio(), 0.0d); + } + + public void testGetSamplerWithUpdatedSamplingRatio() { + Settings settings = Settings.builder().put(TRACER_EXPORTER_DELAY_SETTING.getKey(), "1s").build(); + TelemetrySettings telemetrySettings = new TelemetrySettings( + Settings.EMPTY, + new ClusterSettings(settings, Set.of(TRACER_SAMPLER_PROBABILITY, TRACER_ENABLED_SETTING)) + ); + + // Probabilistic Sampler + ProbabilisticSampler probabilisticSampler = new ProbabilisticSampler(telemetrySettings); + assertEquals(0.01d, probabilisticSampler.getSamplingRatio(), 0.0d); + + telemetrySettings.setSamplingProbability(0.02); + + // Need to call getSampler() to update the value of tracerHeadSamplerSamplingRatio + Sampler updatedProbabilisticSampler = probabilisticSampler.getSampler(); + assertEquals(0.02, probabilisticSampler.getSamplingRatio(), 0.0d); + } + +} diff --git a/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/RequestSamplerTests.java b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/RequestSamplerTests.java new file mode 100644 index 0000000000000..facf04623ec46 --- /dev/null +++ b/plugins/telemetry-otel/src/test/java/org/opensearch/telemetry/tracing/sampler/RequestSamplerTests.java @@ -0,0 +1,92 @@ +/* + * SPDX-License-Identifier: Apache-2.0 + * + * The OpenSearch Contributors require contributions made to + * this file be licensed under the Apache-2.0 license or a + * compatible open source license. + */ + +package org.opensearch.telemetry.tracing.sampler; + +import org.opensearch.test.OpenSearchTestCase; + +import java.util.Collections; + +import io.opentelemetry.api.common.AttributeKey; +import io.opentelemetry.api.common.Attributes; +import io.opentelemetry.api.trace.SpanKind; +import io.opentelemetry.context.Context; +import io.opentelemetry.sdk.trace.samplers.Sampler; +import io.opentelemetry.sdk.trace.samplers.SamplingResult; + +import static org.mockito.ArgumentMatchers.any; +import static org.mockito.ArgumentMatchers.anyString; +import static org.mockito.Mockito.mock; +import static org.mockito.Mockito.never; +import static org.mockito.Mockito.verify; +import static org.mockito.Mockito.when; + +public class RequestSamplerTests extends OpenSearchTestCase { + + public void testShouldSampleWithTraceAttributeAsTrue() { + + // Create a mock default sampler + Sampler defaultSampler = mock(Sampler.class); + when(defaultSampler.shouldSample(any(), anyString(), anyString(), any(), any(), any())).thenReturn(SamplingResult.drop()); + + // Create an instance of HeadSampler with the mock default sampler + RequestSampler requestSampler = new RequestSampler(defaultSampler); + + // Create a mock Context and Attributes + Context parentContext = mock(Context.class); + Attributes attributes = Attributes.of(AttributeKey.stringKey("trace"), "true"); + + // Call shouldSample on HeadSampler + SamplingResult result = requestSampler.shouldSample( + parentContext, + "traceId", + "spanName", + SpanKind.INTERNAL, + attributes, + Collections.emptyList() + ); + + assertEquals(SamplingResult.recordAndSample(), result); + + // Verify that the default sampler's shouldSample method was not called + verify(defaultSampler, never()).shouldSample(any(), anyString(), anyString(), any(), any(), any()); + } + + public void testShouldSampleWithoutTraceAttribute() { + + // Create a mock default sampler + Sampler defaultSampler = mock(Sampler.class); + when(defaultSampler.shouldSample(any(), anyString(), anyString(), any(), any(), any())).thenReturn( + SamplingResult.recordAndSample() + ); + + // Create an instance of HeadSampler with the mock default sampler + RequestSampler requestSampler = new RequestSampler(defaultSampler); + + // Create a mock Context and Attributes + Context parentContext = mock(Context.class); + Attributes attributes = Attributes.empty(); + + // Call shouldSample on HeadSampler + SamplingResult result = requestSampler.shouldSample( + parentContext, + "traceId", + "spanName", + SpanKind.INTERNAL, + attributes, + Collections.emptyList() + ); + + // Verify that HeadSampler returned SamplingResult.recordAndSample() + assertEquals(SamplingResult.recordAndSample(), result); + + // Verify that the default sampler's shouldSample method was called + verify(defaultSampler).shouldSample(any(), anyString(), anyString(), any(), any(), any()); + } + +} diff --git a/server/src/main/java/org/opensearch/common/settings/ClusterSettings.java b/server/src/main/java/org/opensearch/common/settings/ClusterSettings.java index 237aabdfec73d..09c24c9b7805d 100644 --- a/server/src/main/java/org/opensearch/common/settings/ClusterSettings.java +++ b/server/src/main/java/org/opensearch/common/settings/ClusterSettings.java @@ -694,6 +694,6 @@ public void apply(Settings value, Settings current, Settings previous) { SearchBootstrapSettings.CONCURRENT_SEGMENT_SEARCH_TARGET_MAX_SLICE_COUNT_SETTING ), List.of(FeatureFlags.TELEMETRY), - List.of(TelemetrySettings.TRACER_ENABLED_SETTING) + List.of(TelemetrySettings.TRACER_ENABLED_SETTING, TelemetrySettings.TRACER_SAMPLER_PROBABILITY) ); } diff --git a/server/src/main/java/org/opensearch/plugins/TelemetryPlugin.java b/server/src/main/java/org/opensearch/plugins/TelemetryPlugin.java index 33dc9b7a0c843..66033df394d9f 100644 --- a/server/src/main/java/org/opensearch/plugins/TelemetryPlugin.java +++ b/server/src/main/java/org/opensearch/plugins/TelemetryPlugin.java @@ -18,7 +18,7 @@ */ public interface TelemetryPlugin { - Optional getTelemetry(TelemetrySettings settings); + Optional getTelemetry(TelemetrySettings telemetrySettings); String getName(); diff --git a/server/src/main/java/org/opensearch/telemetry/TelemetrySettings.java b/server/src/main/java/org/opensearch/telemetry/TelemetrySettings.java index 7c9e0d5ac8097..aa11a2879e4d7 100644 --- a/server/src/main/java/org/opensearch/telemetry/TelemetrySettings.java +++ b/server/src/main/java/org/opensearch/telemetry/TelemetrySettings.java @@ -23,12 +23,27 @@ public class TelemetrySettings { Setting.Property.Dynamic ); + /** + * Probability of sampler + */ + public static final Setting TRACER_SAMPLER_PROBABILITY = Setting.doubleSetting( + "telemetry.tracer.sampler.probability", + 0.01d, + 0.00d, + 1.00d, + Setting.Property.NodeScope, + Setting.Property.Dynamic + ); + private volatile boolean tracingEnabled; + private volatile double samplingProbability; public TelemetrySettings(Settings settings, ClusterSettings clusterSettings) { this.tracingEnabled = TRACER_ENABLED_SETTING.get(settings); + this.samplingProbability = TRACER_SAMPLER_PROBABILITY.get(settings); clusterSettings.addSettingsUpdateConsumer(TRACER_ENABLED_SETTING, this::setTracingEnabled); + clusterSettings.addSettingsUpdateConsumer(TRACER_SAMPLER_PROBABILITY, this::setSamplingProbability); } public void setTracingEnabled(boolean tracingEnabled) { @@ -39,4 +54,18 @@ public boolean isTracingEnabled() { return tracingEnabled; } + /** + * Set sampling ratio + * @param samplingProbability double + */ + public void setSamplingProbability(double samplingProbability) { + this.samplingProbability = samplingProbability; + } + + /** + * Get sampling ratio + */ + public double getTracerHeadSamplerSamplingRatio() { + return samplingProbability; + } }