Add a ThreadPoolFactory to propagate OpenTelemetry contexts

Signed-off-by: Adriano Machado <[email protected]>

components/camel-opentelemetry/src/generated/resources/META-INF/services/org/apache/camel/thread-pool-factory

@@ -0,0 +1,2 @@
+# Generated by camel build tools - do NOT edit this file!
+class=org.apache.camel.opentelemetry.OpenTelemetryInstrumentedThreadPoolFactory

components/camel-opentelemetry/src/main/java/org/apache/camel/opentelemetry/OpenTelemetryInstrumentedThreadPoolFactory.java

@@ -0,0 +1,68 @@
+/*
+ * 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.opentelemetry;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.TimeUnit;
+
+import io.opentelemetry.context.Context;
+import org.apache.camel.spi.ThreadPoolFactory;
+import org.apache.camel.spi.ThreadPoolProfile;
+import org.apache.camel.spi.annotations.JdkService;
+import org.apache.camel.support.DefaultThreadPoolFactory;
+
+@JdkService(ThreadPoolFactory.FACTORY)
+public class OpenTelemetryInstrumentedThreadPoolFactory extends DefaultThreadPoolFactory implements ThreadPoolFactory {
+
+    @Override
+    public ExecutorService newCachedThreadPool(ThreadFactory threadFactory) {
+        return Context.current().wrap(super.newCachedThreadPool(threadFactory));
+    }
+
+    @Override
+    public ExecutorService newThreadPool(
+            int corePoolSize,
+            int maxPoolSize,
+            long keepAliveTime,
+            TimeUnit timeUnit,
+            int maxQueueSize,
+            boolean allowCoreThreadTimeOut,
+            RejectedExecutionHandler rejectedExecutionHandler,
+            ThreadFactory threadFactory)
+            throws IllegalArgumentException {
+
+        ExecutorService executorService = super.newThreadPool(
+                corePoolSize,
+                maxPoolSize,
+                keepAliveTime,
+                timeUnit,
+                maxQueueSize,
+                allowCoreThreadTimeOut,
+                rejectedExecutionHandler,
+                threadFactory);
+
+        return Context.current().wrap(executorService);
+    }
+
+    @Override
+    public ScheduledExecutorService newScheduledThreadPool(ThreadPoolProfile profile, ThreadFactory threadFactory) {
+        return Context.current().wrap(super.newScheduledThreadPool(profile, threadFactory));
+    }
+}

core/camel-api/src/main/java/org/apache/camel/spi/ThreadPoolFactory.java

@@ -24,7 +24,7 @@
  * Creates ExecutorService and ScheduledExecutorService objects that work with a thread pool for a given
  * ThreadPoolProfile and ThreadFactory.
  *
- * This interface allows to customize the creation of these objects to adapt camel for application servers and other
+ * This interface allows customizing the creation of these objects to adapt camel for application servers and other
  * environments where thread pools should not be created with the jdk methods
  */
 public interface ThreadPoolFactory {
@@ -38,8 +38,9 @@ public interface ThreadPoolFactory {
      * Creates a new cached thread pool
      * <p/>
      * The cached thread pool is a term from the JDK from the method
-     * {@link java.util.concurrent.Executors#newCachedThreadPool()}. Typically it will have no size limit (this is why
-     * it is handled separately
+     * {@link java.util.concurrent.Executors#newCachedThreadPool()}.
+     * <p/>
+     * Typically, it will have no size limit (this is why it is handled separately)
      *
      * @param  threadFactory factory for creating threads
      * @return               the created thread pool