Introduce withParentOnly for @observed

Take tracing for example, we may no want to create root span by @observed, they should be created if a root http span present.
micrometer-metrics · May 18, 2023 · fcf9953 · fcf9953
1 parent 77d9cdb
commit fcf9953
Show file tree

Hide file tree

Showing 3 changed files with 64 additions and 0 deletions.
diff --git a/micrometer-observation/src/main/java/io/micrometer/observation/annotation/Observed.java b/micrometer-observation/src/main/java/io/micrometer/observation/annotation/Observed.java
@@ -27,6 +27,7 @@
  * Annotation to mark classes and methods that you want to observe.
  *
  * @author Jonatan Ivanov
+ * @author Yanming Zhou
  * @since 1.10.0
  */
 @Target({ ElementType.ANNOTATION_TYPE, ElementType.TYPE, ElementType.METHOD })
@@ -52,4 +53,10 @@
      */
     String[] lowCardinalityKeyValues() default {};
 
+    /**
+     * Returns {@code true} if {@link Observation} should not be started without parent.
+     * @return {@code true} if {@link Observation} should not be started without parent.
+     */
+    boolean withParentOnly() default false;
+
 }
diff --git a/micrometer-observation/src/main/java/io/micrometer/observation/aop/ObservedAspect.java b/micrometer-observation/src/main/java/io/micrometer/observation/aop/ObservedAspect.java
@@ -68,6 +68,7 @@
  * </pre>
  *
  * @author Jonatan Ivanov
+ * @author Yanming Zhou
  * @since 1.10.0
  */
 @Aspect
@@ -131,6 +132,9 @@ public Object observeMethod(ProceedingJoinPoint pjp) throws Throwable {
     private Object observe(ProceedingJoinPoint pjp, Method method, Observed observed) throws Throwable {
         Observation observation = ObservedAspectObservationDocumentation.of(pjp, observed, this.registry,
                 this.observationConvention);
+        if (observed.withParentOnly() && observation.getContextView().getParentObservation() == null) {
+            return pjp.proceed();
+        }
         if (CompletionStage.class.isAssignableFrom(method.getReturnType())) {
             observation.start();
             Observation.Scope scope = observation.openScope();

diff --git a/micrometer-observation/src/test/java/io/micrometer/observation/aop/ObservedAspectTests.java b/micrometer-observation/src/test/java/io/micrometer/observation/aop/ObservedAspectTests.java
@@ -334,6 +334,35 @@ void skipPredicateShouldTakeEffectForClass() {
         TestObservationRegistryAssert.assertThat(registry).doesNotHaveAnyObservation();
     }
 
+    @Test
+    void withParentOnlyObservationShouldNotBeStartedWithoutParent() {
+        registry.observationConfig().observationHandler(new ObservationTextPublisher());
+
+        AspectJProxyFactory pf = new AspectJProxyFactory(new InternalService());
+        pf.addAspect(new ObservedAspect(registry));
+
+        InternalService internalService = pf.getProxy();
+        internalService.call();
+
+        TestObservationRegistryAssert.assertThat(registry).doesNotHaveAnyObservation();
+    }
+
+    @Test
+    void withParentOnlyObservationShouldBeStartedIfParentPresent() {
+        registry.observationConfig().observationHandler(new ObservationTextPublisher());
+
+        AspectJProxyFactory pf = new AspectJProxyFactory(new InternalService());
+        pf.addAspect(new ObservedAspect(registry));
+        InternalService internalService = pf.getProxy();
+        pf = new AspectJProxyFactory(new ExternalService(internalService));
+        pf.addAspect(new ObservedAspect(registry));
+
+        ExternalService externalService = pf.getProxy();
+        externalService.call();
+
+        TestObservationRegistryAssert.assertThat(registry).hasNumberOfObservationsEqualTo(2);
+    }
+
     static class ObservedService {
 
         @Observed(name = "test.call", contextualName = "test#call",
@@ -443,4 +472,28 @@ public boolean supportsContext(@NonNull Observation.Context context) {
 
     }
 
+    static class ExternalService {
+
+        private final InternalService internalService;
+
+        ExternalService(InternalService internalService) {
+            this.internalService = internalService;
+        }
+
+        @Observed
+        void call() {
+            internalService.call();
+        }
+
+    }
+
+    static class InternalService {
+
+        @Observed(withParentOnly = true)
+        void call() {
+            System.out.println("call");
+        }
+
+    }
+
 }