Added the getCurrentObservationScope method

micrometer-observation-test/src/main/java/io/micrometer/core/tck/TestObservationRegistry.java

@@ -55,8 +55,13 @@ public Observation getCurrentObservation() {
     }
 
     @Override
-    public void setCurrentObservation(Observation current) {
-        this.delegate.setCurrentObservation(current);
+    public Observation.Scope getCurrentObservationScope() {
+        return this.delegate.getCurrentObservationScope();
+    }
+
+    @Override
+    public void setCurrentObservationScope(Observation.Scope current) {
+        this.delegate.setCurrentObservationScope(current);
     }
 
     @Override

micrometer-observation/src/main/java/io/micrometer/observation/NoopObservationRegistry.java

@@ -42,7 +42,13 @@ public Observation getCurrentObservation() {
     }
 
     @Override
-    public void setCurrentObservation(Observation current) {
+    public Observation.Scope getCurrentObservationScope() {
+        return NoopObservation.NoOpScope.INSTANCE;
+    }
+
+    @Override
+    public void setCurrentObservationScope(Observation.Scope current) {
+
     }
 
     @Override

micrometer-observation/src/main/java/io/micrometer/observation/ObservationRegistry.java

@@ -57,10 +57,21 @@ static ObservationRegistry create() {
     Observation getCurrentObservation();
 
     /**
-     * Sets the observation as current.
-     * @param current observation
+     * When previously set will allow to retrieve the {@link Observation.Scope} at any
+     * point in time.
+     *
+     * Example: if an {@link Observation} was put in {@link Observation.Scope} then this
+     * method will return the current present {@link Observation.Scope}.
+     * @return current observation scope or {@code null} if it's not present
+     */
+    @Nullable
+    Observation.Scope getCurrentObservationScope();
+
+    /**
+     * Sets the observation scope as current.
+     * @param current observation scope
      */
-    void setCurrentObservation(@Nullable Observation current);
+    void setCurrentObservationScope(@Nullable Observation.Scope current);
 
     /**
      * Configuration options for this registry.

micrometer-observation/src/main/java/io/micrometer/observation/SimpleObservation.java

@@ -152,13 +152,13 @@ static class SimpleScope implements Scope {
         private final SimpleObservation currentObservation;
 
         @Nullable
-        private final Observation previousObservation;
+        private final Observation.Scope previousObservation;
 
         SimpleScope(ObservationRegistry registry, SimpleObservation current) {
             this.registry = registry;
             this.currentObservation = current;
-            this.previousObservation = registry.getCurrentObservation();
-            this.registry.setCurrentObservation(current);
+            this.previousObservation = registry.getCurrentObservationScope();
+            this.registry.setCurrentObservationScope(this);
         }
 
         @Override
@@ -168,7 +168,7 @@ public Observation getCurrentObservation() {
 
         @Override
         public void close() {
-            this.registry.setCurrentObservation(previousObservation);
+            this.registry.setCurrentObservationScope(previousObservation);
             this.currentObservation.notifyOnScopeClosed();
         }
 

micrometer-observation/src/main/java/io/micrometer/observation/SimpleObservationRegistry.java

@@ -27,18 +27,27 @@
  */
 class SimpleObservationRegistry implements ObservationRegistry {
 
-    private static final ThreadLocal<Observation> localObservation = new ThreadLocal<>();
+    private static final ThreadLocal<Observation.Scope> localObservation = new ThreadLocal<>();
 
     private final ObservationConfig observationConfig = new ObservationConfig();
 
     @Nullable
     @Override
     public Observation getCurrentObservation() {
+        Observation.Scope scope = localObservation.get();
+        if (scope != null) {
+            return scope.getCurrentObservation();
+        }
+        return null;
+    }
+
+    @Override
+    public Observation.Scope getCurrentObservationScope() {
         return localObservation.get();
     }
 
     @Override
-    public void setCurrentObservation(@Nullable Observation current) {
+    public void setCurrentObservationScope(Observation.Scope current) {
         localObservation.set(current);
     }