Camel 23283 micrometer span scope

components/camel-micrometer-observability/src/main/java/org/apache/camel/micrometer/observability/MicrometerObservabilitySpanAdapter.java

@@ -18,16 +18,20 @@
 
 import java.util.Map;
 
+import io.micrometer.tracing.Tracer;
 import org.apache.camel.telemetry.Span;
 
 public class MicrometerObservabilitySpanAdapter implements Span {
 
     private static final String DEFAULT_EVENT_NAME = "log";
 
     private final io.micrometer.tracing.Span span;
+    private final Tracer tracer;
+    private Tracer.SpanInScope spanInScope;
 
-    public MicrometerObservabilitySpanAdapter(io.micrometer.tracing.Span span) {
+    public MicrometerObservabilitySpanAdapter(io.micrometer.tracing.Span span, Tracer tracer) {
         this.span = span;
+        this.tracer = tracer;
     }
 
     @Override
@@ -64,14 +68,18 @@ protected io.micrometer.tracing.Span getSpan() {
 
     protected void activate() {
         this.span.start();
-    }
-
-    protected void close() {
-        this.span.end();
+        this.spanInScope = this.tracer.withSpan(this.span);
     }
 
     protected void deactivate() {
+        if (this.spanInScope != null) {
+            this.spanInScope.close();
+            this.spanInScope = null;
+        }
+    }
 
+    protected void close() {
+        this.span.end();
     }
 
     @Override

components/camel-micrometer-observability/src/main/java/org/apache/camel/micrometer/observability/MicrometerObservabilityTracer.java

@@ -136,11 +136,27 @@ public Span create(String spanName, Span parent, SpanContextPropagationExtractor
                     return extractor.get(key) == null ? null : (String) extractor.get(key);
                 });
 
+                // If no trace headers were found in the carrier, any parent context in
+                // the builder came from the thread-local scope (e.g., Context.current()
+                // for OTel). This can be stale when async processing moves span lifecycle
+                // to a different thread, leaving the original thread's scope un-cleaned.
+                // Force a root span in that case to prevent trace contamination.
+                boolean hasTraceHeaders = false;
+                for (String field : propagator.fields()) {
+                    if (extractor.get(field) != null) {
+                        hasTraceHeaders = true;
+                        break;
+                    }
+                }
+                if (!hasTraceHeaders) {
+                    builder.setNoParent();
+                }
+
                 span = builder.start();
             }
             span.name(spanName);
 
-            return new MicrometerObservabilitySpanAdapter(span);
+            return new MicrometerObservabilitySpanAdapter(span, tracer);
         }
 
         @Override

components/camel-micrometer-observability/src/test/java/org/apache/camel/micrometer/observability/MicrometerObservabilityTracerPropagationTestSupport.java

@@ -18,10 +18,12 @@
 
 import java.util.List;
 
+import io.micrometer.tracing.Tracer;
 import io.micrometer.tracing.otel.bridge.OtelCurrentTraceContext;
 import io.micrometer.tracing.otel.bridge.OtelPropagator;
 import io.micrometer.tracing.otel.bridge.OtelTracer;
 import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.context.Context;
 import io.opentelemetry.context.propagation.ContextPropagators;
 import io.opentelemetry.sdk.trace.data.SpanData;
 import org.apache.camel.CamelContext;
@@ -37,9 +39,15 @@ public class MicrometerObservabilityTracerPropagationTestSupport extends Exchang
 
     protected CamelOpenTelemetryExtension otelExtension = CamelOpenTelemetryExtension.create();
     protected MicrometerObservabilityTracer tst = new MicrometerObservabilityTracer();
+    protected Tracer micrometerTracer;
 
     @Override
     protected CamelContext createCamelContext() throws Exception {
+        // Clear any stale OTel context left by previous tests (e.g., from async thread
+        // handoff where deactivate() ran on a different thread). OtelPropagator.extract()
+        // reads Context.current() directly, so stale spans would become unwanted parents.
+        Context.root().makeCurrent();
+
         CamelContext context = super.createCamelContext();
 
         ContextPropagators propagators = otelExtension.getPropagators();
@@ -48,7 +56,7 @@ protected CamelContext createCamelContext() throws Exception {
         OtelPropagator otelPropagator = new OtelPropagator(propagators, otelTracer);
         OtelCurrentTraceContext currentTraceContext = new OtelCurrentTraceContext();
         // We must convert the Otel Tracer into a micrometer Tracer
-        io.micrometer.tracing.Tracer micrometerTracer = new OtelTracer(
+        micrometerTracer = new OtelTracer(
                 otelTracer,
                 currentTraceContext,
                 null);

components/camel-micrometer-observability/src/test/java/org/apache/camel/micrometer/observability/SpanScopeTest.java

@@ -0,0 +1,97 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.camel.micrometer.observability;
+
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
+
+import io.opentelemetry.sdk.trace.data.SpanData;
+import org.apache.camel.RoutesBuilder;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.micrometer.observability.CamelOpenTelemetryExtension.OtelTrace;
+import org.apache.camel.telemetry.Op;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+/**
+ * Verifies that spans are properly put in scope during route execution. This is critical for routes triggered by
+ * consumers that don't have framework-level tracing (e.g., JMS), where Camel must manage the span scope itself.
+ *
+ * Without proper scope management, {@code tracer.currentSpan()} returns null during route execution, which prevents the
+ * trace from being exported and for downstream instrumentation from attaching to the Camel trace.
+ */
+public class SpanScopeTest extends MicrometerObservabilityTracerPropagationTestSupport {
+
+    private final AtomicReference<io.micrometer.tracing.Span> capturedCurrentSpan = new AtomicReference<>();
+
+    @Test
+    void testSpanIsInScopeDuringRouteExecution() {
+        template.sendBody("direct:start", "Test Message");
+
+        // The processor captured tracer.currentSpan() during route execution.
+        io.micrometer.tracing.Span current = capturedCurrentSpan.get();
+        assertNotNull(current);
+    }
+
+    @Test
+    void testCapturedSpanMatchesTraceId() {
+        template.sendBody("direct:start", "Test Message");
+
+        io.micrometer.tracing.Span current = capturedCurrentSpan.get();
+        assertNotNull(current);
+
+        // The captured current span should belong to the same trace as the recorded spans
+        Map<String, OtelTrace> traces = otelExtension.getTraces();
+        assertEquals(1, traces.size());
+        String expectedTraceId = traces.keySet().iterator().next();
+        List<SpanData> spans = traces.get(expectedTraceId).getSpans();
+
+        SpanData receivedSpan = getSpan(spans, "direct://start", Op.EVENT_RECEIVED);
+        assertEquals(expectedTraceId, current.context().traceId());
+        assertEquals(receivedSpan.getSpanId(), current.context().spanId());
+    }
+
+    @Test
+    void testSpanScopeIsCleanedUpAfterRouteExecution() {
+        template.sendBody("direct:start", "Test Message");
+
+        // After the route completes, the scope should be closed and
+        // tracer.currentSpan() should return null
+        io.micrometer.tracing.Span afterRoute = micrometerTracer.currentSpan();
+        assertNull(afterRoute);
+    }
+
+    @Override
+    protected RoutesBuilder createRouteBuilder() {
+        return new RouteBuilder() {
+            @Override
+            public void configure() {
+                from("direct:start")
+                        .routeId("start")
+                        .process(exchange -> {
+                            capturedCurrentSpan.set(micrometerTracer.currentSpan());
+                        })
+                        .to("log:info");
+            }
+        };
+    }
+
+}