testclient: add regression test for LoadSimulationController executor…

pulsar-testclient/src/main/java/org/apache/pulsar/testclient/LoadSimulationController.java

@@ -37,6 +37,7 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
 import org.apache.bookkeeper.util.ZkUtils;
 import org.apache.pulsar.broker.loadbalance.LoadManager;
 import org.apache.pulsar.common.policies.data.ResourceQuota;
@@ -63,7 +64,7 @@
 @Command(name = "simulation-controller",
         description = "Provides a shell for the user to dictate how simulation clients should "
         + "incur load.")
-public class LoadSimulationController extends CmdBase{
+public class LoadSimulationController extends CmdBase implements AutoCloseable {
     private static final Logger log = LoggerFactory.getLogger(LoadSimulationController.class);
 
     // Input streams for each client to send commands through.
@@ -77,7 +78,20 @@ public class LoadSimulationController extends CmdBase{
 
     private Random random;
 
-    private static final ExecutorService threadPool = Executors.newCachedThreadPool();
+    private final ExecutorService threadPool = Executors.newCachedThreadPool();
+
+    @Override
+    public void close() {
+        threadPool.shutdown();
+        try {
+            if (!threadPool.awaitTermination(5, TimeUnit.SECONDS)) {
+                threadPool.shutdownNow();
+            }
+        } catch (InterruptedException e) {
+            threadPool.shutdownNow();
+            Thread.currentThread().interrupt();
+        }
+    }
 
     // picocli arguments for starting a controller via main.
 
@@ -690,18 +704,22 @@ public void start() throws Exception {
      */
     @Override
     public void run() throws Exception {
-        random = new Random();
-        clients = this.clientHostNames.split(",");
-        final Socket[] sockets = new Socket[clients.length];
-        inputStreams = new DataInputStream[clients.length];
-        outputStreams = new DataOutputStream[clients.length];
-        log.info("Found {} clients:", clients.length);
-        for (int i = 0; i < clients.length; ++i) {
-            sockets[i] = new Socket(clients[i], clientPort);
-            inputStreams[i] = new DataInputStream(sockets[i].getInputStream());
-            outputStreams[i] = new DataOutputStream(sockets[i].getOutputStream());
-            log.info("Connected to {}", clients[i]);
+        try {
+            random = new Random();
+            clients = this.clientHostNames.split(",");
+            final Socket[] sockets = new Socket[clients.length];
+            inputStreams = new DataInputStream[clients.length];
+            outputStreams = new DataOutputStream[clients.length];
+            log.info("Found {} clients:", clients.length);
+            for (int i = 0; i < clients.length; ++i) {
+                sockets[i] = new Socket(clients[i], clientPort);
+                inputStreams[i] = new DataInputStream(sockets[i].getInputStream());
+                outputStreams[i] = new DataOutputStream(sockets[i].getOutputStream());
+                log.info("Connected to {}", clients[i]);
+            }
+            start();
+        } finally {
+            close();
         }
-        start();
     }
 }

pulsar-testclient/src/test/java/org/apache/pulsar/testclient/LoadSimulationControllerTest.java

@@ -0,0 +1,67 @@
+/*
+ * 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.pulsar.testclient;
+
+import java.lang.reflect.Field;
+import java.util.Map;
+import java.util.concurrent.ExecutorService;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class LoadSimulationControllerTest {
+
+    @Test
+    public void shouldLeakThreadsWhenExecutorIsNotShutdown() throws Exception {
+        LoadSimulationController controller = new LoadSimulationController();
+        Field threadPoolField = LoadSimulationController.class.getDeclaredField("threadPool");
+        threadPoolField.setAccessible(true);
+        ExecutorService threadPool = (ExecutorService) threadPoolField.get(controller);
+
+        threadPool.submit(() -> {
+            try {
+                Thread.sleep(50);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        });
+
+        Thread.sleep(100);
+
+        controller.close();
+
+        long poolThreadCount = 0;
+        for (int i = 0; i < 20; i++) {
+            Map<Thread, StackTraceElement[]> threads = Thread.getAllStackTraces();
+            poolThreadCount = threads.keySet().stream()
+                    .filter(Thread::isAlive)
+                    .filter(t -> !t.isDaemon())
+                    .filter(t -> t.getName().startsWith("pool-"))
+                    .count();
+            if (poolThreadCount == 0) {
+                break;
+            }
+            Thread.sleep(25);
+        }
+
+        assertTrue(poolThreadCount == 0,
+                String.format("Found %d alive non-daemon pool- threads after close", poolThreadCount));
+    }
+}
+