add config support for BaggageSpanProcessor

baggage-processor/README.md

@@ -42,8 +42,18 @@ Pattern pattern = Pattern.compile("^key.+");
 new BaggageSpanProcessor(baggageKey -> pattern.matcher(baggageKey).matches())
 ```
 
+## Usage with SDK auto-configuration
+
+If you are using the OpenTelemetry SDK auto-configuration, you can add the span processor this
+library to configure the span processor.
+
+| Property                                  | Description                                                                                     |
+|-------------------------------------------|-------------------------------------------------------------------------------------------------|
+| otel.traces.baggage-to-attributes.include | Add baggage items to span attributes, e.g. `key1,key2` or `*` to add all baggage items as keys. |
+
 ## Component owners
 
 - [Mike Golsmith](https://github.com/MikeGoldsmith), Honeycomb
+- [Gregor Zeitlinger](https://github.com/zeitlinger), Grafana
 
 Learn more about component owners in [component_owners.yml](../.github/component_owners.yml).

baggage-processor/build.gradle.kts

@@ -10,6 +10,8 @@ otelJava.moduleName.set("io.opentelemetry.contrib.baggage.processor")
 dependencies {
   api("io.opentelemetry:opentelemetry-api")
   api("io.opentelemetry:opentelemetry-sdk")
+  implementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure-spi")
 
   testImplementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure")
+  testImplementation("org.mockito:mockito-inline")
 }

baggage-processor/src/main/java/io/opentelemetry/contrib/baggage/processor/BaggageSpanProcessorCustomizer.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.contrib.baggage.processor;
+
+import io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizer;
+import io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizerProvider;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.trace.SdkTracerProviderBuilder;
+import java.util.List;
+
+public class BaggageSpanProcessorCustomizer implements AutoConfigurationCustomizerProvider {
+  @Override
+  public void customize(AutoConfigurationCustomizer autoConfigurationCustomizer) {
+    autoConfigurationCustomizer.addTracerProviderCustomizer(
+        (sdkTracerProviderBuilder, config) -> {
+          addSpanProcessor(sdkTracerProviderBuilder, config);
+          return sdkTracerProviderBuilder;
+        });
+  }
+
+  private static void addSpanProcessor(
+      SdkTracerProviderBuilder sdkTracerProviderBuilder, ConfigProperties config) {
+    List<String> keys = config.getList("otel.traces.baggage-to-attributes.include");
+
+    if (keys.isEmpty()) {
+      return;
+    }
+
+    sdkTracerProviderBuilder.addSpanProcessor(createProcessor(keys));
+  }
+
+  static BaggageSpanProcessor createProcessor(List<String> keys) {
+    if (keys.size() == 1 && keys.get(0).equals("*")) {
+      return new BaggageSpanProcessor(BaggageSpanProcessor.allowAllBaggageKeys);
+    }
+    return new BaggageSpanProcessor(keys::contains);
+  }
+}

baggage-processor/src/main/resources/META-INF/services/io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizerProvider

@@ -0,0 +1 @@
+io.opentelemetry.contrib.baggage.processor.BaggageSpanProcessorCustomizer

baggage-processor/src/test/java/io/opentelemetry/contrib/baggage/processor/BaggageSpanProcessorCustomizerTest.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.contrib.baggage.processor;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import io.opentelemetry.api.baggage.Baggage;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.Scope;
+import io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizer;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.DefaultConfigProperties;
+import io.opentelemetry.sdk.trace.ReadWriteSpan;
+import io.opentelemetry.sdk.trace.SdkTracerProviderBuilder;
+import java.util.Collections;
+import java.util.Map;
+import java.util.function.BiFunction;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class BaggageSpanProcessorCustomizerTest {
+
+  @Test
+  void test_customizer() {
+    assertCustomizer(Collections.emptyMap(), 0);
+    assertCustomizer(
+        Collections.singletonMap("otel.traces.baggage-to-attributes.include", "key"), 1);
+  }
+
+  private static void assertCustomizer(
+      Map<String, String> properties, int addedSpanProcessorTimes) {
+    AutoConfigurationCustomizer customizer = Mockito.mock(AutoConfigurationCustomizer.class);
+    new BaggageSpanProcessorCustomizer().customize(customizer);
+    @SuppressWarnings("unchecked")
+    ArgumentCaptor<BiFunction<SdkTracerProviderBuilder, ConfigProperties, SdkTracerProviderBuilder>>
+        captor = ArgumentCaptor.forClass(BiFunction.class);
+    verify(customizer, times(1)).addTracerProviderCustomizer(captor.capture());
+
+    SdkTracerProviderBuilder builder = Mockito.mock(SdkTracerProviderBuilder.class);
+    SdkTracerProviderBuilder apply =
+        captor.getValue().apply(builder, DefaultConfigProperties.createFromMap(properties));
+    assertThat(apply).isSameAs(builder);
+
+    verify(builder, times(addedSpanProcessorTimes)).addSpanProcessor(Mockito.any());
+  }
+
+  @Test
+  public void test_baggageSpanProcessor_adds_attributes_to_spans(@Mock ReadWriteSpan span) {
+    try (BaggageSpanProcessor processor =
+        BaggageSpanProcessorCustomizer.createProcessor(Collections.singletonList("*"))) {
+      try (Scope ignore = Baggage.current().toBuilder().put("key", "value").build().makeCurrent()) {
+        processor.onStart(Context.current(), span);
+        verify(span).setAttribute("key", "value");
+      }
+    }
+  }
+
+  @Test
+  public void test_baggageSpanProcessor_adds_attributes_to_spans_when_key_filter_matches(
+      @Mock ReadWriteSpan span) {
+    try (BaggageSpanProcessor processor =
+        BaggageSpanProcessorCustomizer.createProcessor(Collections.singletonList("key"))) {
+      try (Scope ignore =
+          Baggage.current().toBuilder()
+              .put("key", "value")
+              .put("other", "value")
+              .build()
+              .makeCurrent()) {
+        processor.onStart(Context.current(), span);
+        verify(span).setAttribute("key", "value");
+        verify(span, Mockito.never()).setAttribute("other", "value");
+      }
+    }
+  }
+}