add SdkTracerProvider.setScopeConfigurator() and support

sdk/trace/src/main/java/io/opentelemetry/sdk/trace/ExtendedSdkTracer.java

@@ -12,16 +12,12 @@
 
 /** {@link ExtendedSdkTracer} is SDK implementation of {@link ExtendedTracer}. */
 final class ExtendedSdkTracer extends SdkTracer implements ExtendedTracer {
-  // TODO: add dedicated API for updating scope config.
-  @SuppressWarnings("FieldCanBeFinal") // For now, allow updating reflectively.
-  private boolean tracerEnabled;
 
   ExtendedSdkTracer(
       TracerSharedState sharedState,
       InstrumentationScopeInfo instrumentationScopeInfo,
       TracerConfig tracerConfig) {
     super(sharedState, instrumentationScopeInfo, tracerConfig);
-    this.tracerEnabled = tracerConfig.isEnabled();
   }
 
   @Override

sdk/trace/src/main/java/io/opentelemetry/sdk/trace/SdkTracer.java

@@ -30,10 +30,9 @@ class SdkTracer implements Tracer {
 
   private final TracerSharedState sharedState;
   private final InstrumentationScopeInfo instrumentationScopeInfo;
-
-  // TODO: add dedicated API for updating scope config.
-  @SuppressWarnings("FieldCanBeFinal") // For now, allow updating reflectively.
-  private boolean tracerEnabled;
+  // deliberately not volatile because of performance concerns
+  // - which means its eventually consistent
+  protected boolean tracerEnabled;
 
   SdkTracer(
       TracerSharedState sharedState,
@@ -79,4 +78,13 @@ public SpanBuilder spanBuilder(String spanName) {
   InstrumentationScopeInfo getInstrumentationScopeInfo() {
     return instrumentationScopeInfo;
   }
+
+  // Visible for testing
+  boolean isEnabled() {
+    return tracerEnabled;
+  }
+
+  void updateTracerConfig(TracerConfig tracerConfig) {
+    this.tracerEnabled = tracerConfig.isEnabled();
+  }
 }

sdk/trace/src/main/java/io/opentelemetry/sdk/trace/SdkTracerProvider.java

@@ -14,6 +14,7 @@
 import io.opentelemetry.sdk.internal.ComponentRegistry;
 import io.opentelemetry.sdk.internal.ScopeConfigurator;
 import io.opentelemetry.sdk.resources.Resource;
+import io.opentelemetry.sdk.trace.internal.SdkTracerProviderUtil;
 import io.opentelemetry.sdk.trace.internal.TracerConfig;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 import java.io.Closeable;
@@ -30,7 +31,9 @@ public final class SdkTracerProvider implements TracerProvider, Closeable {
   static final String DEFAULT_TRACER_NAME = "";
   private final TracerSharedState sharedState;
   private final ComponentRegistry<SdkTracer> tracerSdkComponentRegistry;
-  private final ScopeConfigurator<TracerConfig> tracerConfigurator;
+  // deliberately not volatile because of performance concerns
+  // - which means its eventually consistent
+  private ScopeConfigurator<TracerConfig> tracerConfigurator;
 
   /**
    * Returns a new {@link SdkTracerProviderBuilder} for {@link SdkTracerProvider}.
@@ -100,6 +103,25 @@ public Sampler getSampler() {
     return sharedState.getSampler();
   }
 
+  /**
+   * Updates the tracer configurator, which computes {@link TracerConfig} for each {@link
+   * InstrumentationScopeInfo}.
+   *
+   * <p>This method is experimental so not public. You may reflectively call it using {@link
+   * SdkTracerProviderUtil#setTracerConfigurator(SdkTracerProvider, ScopeConfigurator)}.
+   *
+   * @see TracerConfig#configuratorBuilder()
+   */
+  void setTracerConfigurator(ScopeConfigurator<TracerConfig> tracerConfigurator) {
+    this.tracerConfigurator = tracerConfigurator;
+    this.tracerSdkComponentRegistry
+        .getComponents()
+        .forEach(
+            sdkTracer ->
+                sdkTracer.updateTracerConfig(
+                    getTracerConfig(sdkTracer.getInstrumentationScopeInfo())));
+  }
+
   /**
    * Attempts to stop all the activity for {@link Tracer}s created by this provider. Calls {@link
    * SpanProcessor#shutdown()} for all registered {@link SpanProcessor}s.

sdk/trace/src/main/java/io/opentelemetry/sdk/trace/internal/SdkTracerProviderUtil.java

@@ -7,6 +7,7 @@
 
 import io.opentelemetry.sdk.common.InstrumentationScopeInfo;
 import io.opentelemetry.sdk.internal.ScopeConfigurator;
+import io.opentelemetry.sdk.trace.SdkTracerProvider;
 import io.opentelemetry.sdk.trace.SdkTracerProviderBuilder;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -24,6 +25,21 @@ public final class SdkTracerProviderUtil {
 
   private SdkTracerProviderUtil() {}
 
+  /** Reflectively set the {@link ScopeConfigurator} to the {@link SdkTracerProvider}. */
+  public static void setTracerConfigurator(
+      SdkTracerProvider sdkTracerProvider, ScopeConfigurator<TracerConfig> scopeConfigurator) {
+    try {
+      Method method =
+          SdkTracerProvider.class.getDeclaredMethod(
+              "setScopeConfigurator", ScopeConfigurator.class);
+      method.setAccessible(true);
+      method.invoke(sdkTracerProvider, scopeConfigurator);
+    } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
+      throw new IllegalStateException(
+          "Error calling setTracerConfigurator on SdkTracerProvider", e);
+    }
+  }
+
   /** Reflectively set the {@link ScopeConfigurator} to the {@link SdkTracerProviderBuilder}. */
   public static void setTracerConfigurator(
       SdkTracerProviderBuilder sdkTracerProviderBuilder,

sdk/trace/src/test/java/io/opentelemetry/sdk/trace/SdkTracerProviderTest.java

@@ -18,7 +18,10 @@
 import io.opentelemetry.sdk.common.Clock;
 import io.opentelemetry.sdk.common.CompletableResultCode;
 import io.opentelemetry.sdk.common.InstrumentationScopeInfo;
+import io.opentelemetry.sdk.internal.ScopeConfigurator;
 import io.opentelemetry.sdk.resources.Resource;
+import io.opentelemetry.sdk.trace.internal.SdkTracerProviderUtil;
+import io.opentelemetry.sdk.trace.internal.TracerConfig;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 import java.util.function.Supplier;
 import org.junit.jupiter.api.BeforeEach;
@@ -184,6 +187,35 @@ void propagatesInstrumentationScopeInfoToTracer() {
     assertThat(((SdkTracer) tracer).getInstrumentationScopeInfo()).isEqualTo(expected);
   }
 
+  @Test
+  void propagatesEnablementToTracerDirectly() {
+    propagatesEnablementToTracer(true);
+  }
+
+  @Test
+  void propagatesEnablementToTracerByUtil() {
+    propagatesEnablementToTracer(false);
+  }
+
+  void propagatesEnablementToTracer(boolean directly) {
+    SdkTracer tracer = (SdkTracer) tracerFactory.get("test");
+    boolean isEnabled = tracer.isEnabled();
+    ScopeConfigurator<TracerConfig> flipConfigurator =
+        new ScopeConfigurator<TracerConfig>() {
+          @Override
+          public TracerConfig apply(InstrumentationScopeInfo scopeInfo) {
+            return isEnabled ? TracerConfig.disabled() : TracerConfig.enabled();
+          }
+        };
+    // all in the same thread, so should see enablement change immediately
+    if (directly) {
+      tracerFactory.setTracerConfigurator(flipConfigurator);
+    } else {
+      SdkTracerProviderUtil.setTracerConfigurator(tracerFactory, flipConfigurator);
+    }
+    assertThat(tracer.isEnabled()).isEqualTo(!isEnabled);
+  }
+
   @Test
   void build_SpanLimits() {
     SpanLimits initialSpanLimits = SpanLimits.builder().build();

sdk/trace/src/test/java/io/opentelemetry/sdk/trace/SdkTracerTest.java

@@ -16,6 +16,7 @@
 import io.opentelemetry.sdk.trace.data.SpanData;
 import io.opentelemetry.sdk.trace.export.BatchSpanProcessor;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
+import io.opentelemetry.sdk.trace.internal.TracerConfig;
 import java.util.Collection;
 import java.util.concurrent.atomic.AtomicLong;
 import org.junit.jupiter.api.Test;
@@ -50,6 +51,14 @@ void getInstrumentationScopeInfo() {
     assertThat(tracer.getInstrumentationScopeInfo()).isEqualTo(instrumentationScopeInfo);
   }
 
+  @Test
+  void updateEnabled() {
+    tracer.updateTracerConfig(TracerConfig.disabled());
+    assertThat(tracer.isEnabled()).isFalse();
+    tracer.updateTracerConfig(TracerConfig.enabled());
+    assertThat(tracer.isEnabled()).isTrue();
+  }
+
   @Test
   void propagatesInstrumentationScopeInfoToSpan() {
     ReadableSpan readableSpan = (ReadableSpan) tracer.spanBuilder("spanName").startSpan();

sdk/trace/src/testIncubating/java/io/opentelemetry/sdk/trace/TracerConfigTest.java

@@ -16,7 +16,6 @@
 import io.opentelemetry.api.incubator.trace.ExtendedTracer;
 import io.opentelemetry.api.trace.Span;
 import io.opentelemetry.api.trace.SpanId;
-import io.opentelemetry.api.trace.Tracer;
 import io.opentelemetry.context.Scope;
 import io.opentelemetry.sdk.common.InstrumentationScopeInfo;
 import io.opentelemetry.sdk.internal.ScopeConfigurator;
@@ -42,9 +41,13 @@ void disableScopes() throws InterruptedException {
             .addSpanProcessor(SimpleSpanProcessor.create(exporter))
             .build();
 
-    Tracer tracerA = tracerProvider.get("tracerA");
-    Tracer tracerB = tracerProvider.get("tracerB");
-    Tracer tracerC = tracerProvider.get("tracerC");
+    ExtendedSdkTracer tracerA = (ExtendedSdkTracer) tracerProvider.get("tracerA");
+    ExtendedSdkTracer tracerB = (ExtendedSdkTracer) tracerProvider.get("tracerB");
+    ExtendedSdkTracer tracerC = (ExtendedSdkTracer) tracerProvider.get("tracerC");
+
+    assertThat(tracerA.isEnabled()).isTrue();
+    assertThat(tracerB.isEnabled()).isFalse();
+    assertThat(tracerC.isEnabled()).isTrue();
 
     Span parent;
     Span child;
@@ -158,4 +161,67 @@ private static Stream<Arguments> tracerConfiguratorArgs() {
         Arguments.of(enableStartsWithD, scopeDog, enabled()),
         Arguments.of(enableStartsWithD, scopeDuck, enabled()));
   }
+
+  @Test
+  void setScopeConfigurator() {
+    // 1. Initially, configure all tracers to be enabled except tracerB
+    InMemorySpanExporter exporter = InMemorySpanExporter.create();
+    SdkTracerProvider tracerProvider =
+        SdkTracerProvider.builder()
+            .addTracerConfiguratorCondition(nameEquals("tracerB"), disabled())
+            .addSpanProcessor(SimpleSpanProcessor.create(exporter))
+            .build();
+
+    ExtendedSdkTracer tracerA = (ExtendedSdkTracer) tracerProvider.get("tracerA");
+    ExtendedSdkTracer tracerB = (ExtendedSdkTracer) tracerProvider.get("tracerB");
+    ExtendedSdkTracer tracerC = (ExtendedSdkTracer) tracerProvider.get("tracerC");
+
+    // verify isEnabled()
+    assertThat(tracerA.isEnabled()).isTrue();
+    assertThat(tracerB.isEnabled()).isFalse();
+    assertThat(tracerC.isEnabled()).isTrue();
+
+    // verify spans are emitted as expected
+    tracerA.spanBuilder("spanA").startSpan().end();
+    tracerB.spanBuilder("spanB").startSpan().end();
+    tracerC.spanBuilder("spanC").startSpan().end();
+    assertThat(exporter.getFinishedSpanItems())
+        .satisfiesExactlyInAnyOrder(
+            span -> assertThat(span).hasName("spanA"), span -> assertThat(span).hasName("spanC"));
+    exporter.reset();
+
+    // 2. Update config to disable all tracers
+    tracerProvider.setTracerConfigurator(
+        ScopeConfigurator.<TracerConfig>builder().setDefault(TracerConfig.disabled()).build());
+
+    // verify isEnabled()
+    assertThat(tracerA.isEnabled()).isFalse();
+    assertThat(tracerB.isEnabled()).isFalse();
+    assertThat(tracerC.isEnabled()).isFalse();
+
+    // verify spans are emitted as expected
+    tracerA.spanBuilder("spanA").startSpan().end();
+    tracerB.spanBuilder("spanB").startSpan().end();
+    tracerC.spanBuilder("spanC").startSpan().end();
+    assertThat(exporter.getFinishedSpanItems()).isEmpty();
+
+    // 3. Update config to restore original
+    tracerProvider.setTracerConfigurator(
+        ScopeConfigurator.<TracerConfig>builder()
+            .addCondition(nameEquals("tracerB"), disabled())
+            .build());
+
+    // verify isEnabled()
+    assertThat(tracerA.isEnabled()).isTrue();
+    assertThat(tracerB.isEnabled()).isFalse();
+    assertThat(tracerC.isEnabled()).isTrue();
+
+    // verify spans are emitted as expected
+    tracerA.spanBuilder("spanA").startSpan().end();
+    tracerB.spanBuilder("spanB").startSpan().end();
+    tracerC.spanBuilder("spanC").startSpan().end();
+    assertThat(exporter.getFinishedSpanItems())
+        .satisfiesExactly(
+            span -> assertThat(span).hasName("spanA"), span -> assertThat(span).hasName("spanC"));
+  }
 }