mxm commented on code in PR #15312: URL: https://github.com/apache/iceberg/pull/15312#discussion_r2890304053
########## core/src/test/java/org/apache/iceberg/util/TestThreadPools.java: ########## @@ -0,0 +1,109 @@ +/* + * 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.iceberg.util; + +import static org.assertj.core.api.Assertions.assertThat; + +import java.time.Duration; +import java.util.concurrent.CountDownLatch; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; +import java.util.concurrent.atomic.AtomicBoolean; +import org.junit.jupiter.api.Test; + +public class TestThreadPools { + + @Test + public void testRemoveShutdownHook() { + try { + assertThat(ThreadPools.isShutdownHookRegistered()).isTrue(); + ThreadPools.removeShutdownHook(); + assertThat(ThreadPools.isShutdownHookRegistered()).isFalse(); + } finally { + ThreadPools.initShutdownHook(); + } + } + + @Test + public void testThreadPoolManagerAddAndShutdown() throws Exception { + ThreadPools.ThreadPoolManager manager = new ThreadPools.ThreadPoolManager(); + + ExecutorService testExecutor = Executors.newFixedThreadPool(2); + + Duration timeout = Duration.ofSeconds(5); + manager.addThreadPool(testExecutor, timeout); + + manager.shutdownAll(); + + assertThat(testExecutor.isShutdown()).isTrue(); + } + + @Test + public void testThreadPoolManagerMultipleShutdowns() throws Exception { + ThreadPools.ThreadPoolManager manager = new ThreadPools.ThreadPoolManager(); + + ExecutorService executor1 = Executors.newFixedThreadPool(1); + ExecutorService executor2 = Executors.newFixedThreadPool(1); + + Duration timeout = Duration.ofSeconds(5); + manager.addThreadPool(executor1, timeout); + manager.addThreadPool(executor2, timeout); + + manager.shutdownAll(); + + assertThat(executor1.isShutdown()).isTrue(); + assertThat(executor2.isShutdown()).isTrue(); + } + + @Test + public void testThreadPoolManagerShutdownNowCalled() throws Exception { + ThreadPools.ThreadPoolManager manager = new ThreadPools.ThreadPoolManager(); + + final AtomicBoolean interrupted = new AtomicBoolean(false); + ExecutorService slowExecutor = Executors.newFixedThreadPool(1); + + manager.addThreadPool(slowExecutor, Duration.ofMillis(50)); + + CountDownLatch threadStarted = new CountDownLatch(1); + CountDownLatch threadInterrupted = new CountDownLatch(1); + + slowExecutor.submit( + () -> { + try { + threadStarted.countDown(); + Thread.sleep(60_000); Review Comment: Should we add a comment that we're not actually waiting 60 seconds here? ########## core/src/main/java/org/apache/iceberg/util/ThreadPools.java: ########## @@ -180,15 +261,74 @@ public static ScheduledExecutorService newScheduledPool(String namePrefix, int p * is suitable for long-lived thread pools that should be automatically cleaned up on JVM * shutdown. */ - public static ScheduledExecutorService newExitingScheduledPool( + public static synchronized ScheduledExecutorService newExitingScheduledPool( String namePrefix, int poolSize, Duration terminationTimeout) { - return MoreExecutors.getExitingScheduledExecutorService( - (ScheduledThreadPoolExecutor) newScheduledPool(namePrefix, poolSize), - terminationTimeout.toMillis(), - TimeUnit.MILLISECONDS); + ScheduledExecutorService service = + Executors.unconfigurableScheduledExecutorService(newScheduledPool(namePrefix, poolSize)); + THREAD_POOL_MANAGER.addThreadPool(service, terminationTimeout); + return service; } private static ThreadFactory newDaemonThreadFactory(String namePrefix) { return new ThreadFactoryBuilder().setDaemon(true).setNameFormat(namePrefix + "-%d").build(); } + + /** Manages the lifecycle of thread pools that need to be shut down gracefully. */ + static class ThreadPoolManager { + private final List<ExecutorServiceWithTimeout> threadPoolsToShutdown = Lists.newArrayList(); + + /** + * Add an executor service to the list of thread pools to be shut down. + * + * @param service the executor service to add + * @param timeout the timeout for shutdown operations + */ + synchronized void addThreadPool(ExecutorService service, Duration timeout) { + threadPoolsToShutdown.add(new ExecutorServiceWithTimeout(service, timeout)); + } + + /** Shut down all registered thread pools. */ + synchronized void shutdownAll() { + long startTime = System.nanoTime(); + List<ExecutorServiceWithTimeout> pendingShutdown = Lists.newArrayList(); + for (ExecutorServiceWithTimeout item : threadPoolsToShutdown) { + item.getService().shutdown(); + pendingShutdown.add(item); + } + threadPoolsToShutdown.clear(); + for (ExecutorServiceWithTimeout item : pendingShutdown) { + long timeElapsed = System.nanoTime() - startTime; + long remainingTime = item.getTimeout().toNanos() - timeElapsed; + if (remainingTime > 0) { + try { + if (!item.service.awaitTermination(remainingTime, TimeUnit.NANOSECONDS)) { + item.getService().shutdownNow(); + } + } catch (InterruptedException ignored) { + // We're shutting down anyway, so just ignore. + } + } else { Review Comment: NIT newline after blocks (Iceberg style) ########## core/src/main/java/org/apache/iceberg/util/ThreadPools.java: ########## @@ -180,15 +261,74 @@ public static ScheduledExecutorService newScheduledPool(String namePrefix, int p * is suitable for long-lived thread pools that should be automatically cleaned up on JVM * shutdown. */ - public static ScheduledExecutorService newExitingScheduledPool( + public static synchronized ScheduledExecutorService newExitingScheduledPool( String namePrefix, int poolSize, Duration terminationTimeout) { - return MoreExecutors.getExitingScheduledExecutorService( - (ScheduledThreadPoolExecutor) newScheduledPool(namePrefix, poolSize), - terminationTimeout.toMillis(), - TimeUnit.MILLISECONDS); + ScheduledExecutorService service = + Executors.unconfigurableScheduledExecutorService(newScheduledPool(namePrefix, poolSize)); + THREAD_POOL_MANAGER.addThreadPool(service, terminationTimeout); + return service; } private static ThreadFactory newDaemonThreadFactory(String namePrefix) { return new ThreadFactoryBuilder().setDaemon(true).setNameFormat(namePrefix + "-%d").build(); } + + /** Manages the lifecycle of thread pools that need to be shut down gracefully. */ + static class ThreadPoolManager { + private final List<ExecutorServiceWithTimeout> threadPoolsToShutdown = Lists.newArrayList(); + + /** + * Add an executor service to the list of thread pools to be shut down. + * + * @param service the executor service to add + * @param timeout the timeout for shutdown operations + */ + synchronized void addThreadPool(ExecutorService service, Duration timeout) { + threadPoolsToShutdown.add(new ExecutorServiceWithTimeout(service, timeout)); + } + + /** Shut down all registered thread pools. */ + synchronized void shutdownAll() { + long startTime = System.nanoTime(); + List<ExecutorServiceWithTimeout> pendingShutdown = Lists.newArrayList(); + for (ExecutorServiceWithTimeout item : threadPoolsToShutdown) { + item.getService().shutdown(); + pendingShutdown.add(item); + } + threadPoolsToShutdown.clear(); Review Comment: NIT newline after blocks (Iceberg style) ########## core/src/main/java/org/apache/iceberg/util/ThreadPools.java: ########## @@ -149,8 +152,86 @@ public static ExecutorService newWorkerPool(String namePrefix, int poolSize) { * that should be automatically cleaned up on JVM shutdown. */ public static ExecutorService newExitingWorkerPool(String namePrefix, int poolSize) { - return MoreExecutors.getExitingExecutorService( - (ThreadPoolExecutor) newFixedThreadPool(namePrefix, poolSize)); + ExecutorService service = + Executors.unconfigurableExecutorService(newFixedThreadPool(namePrefix, poolSize)); + THREAD_POOL_MANAGER.addThreadPool(service, DEFAULT_SHUTDOWN_TIMEOUT); + return service; + } + + /** + * Force manual shutdown of the thread pools created via the {@link #newExitingWorkerPool(String, + * int)}. + * + * <p>This method allows: (1) to stop thread pools manually, to avoid leaks in hot-reload + * environments; (2) opt-out of the standard shutdown mechanism to manage graceful service stops + * (and commit the last pending files, if the client application needs to react to shutdown hooks + * on its own). + * + * <p>Please only call this method at the end of the intended usage of the library, and NEVER + * before, as this method will stop thread pools required for normal library workflows. + */ + public static void shutdownThreadPools() { + THREAD_POOL_MANAGER.shutdownAll(); + removeShutdownHook(); + } + + /** + * Initialize a shutdown hook to stop the thread pools created via the {@link + * #newExitingWorkerPool(String, int)}. + */ + @SuppressWarnings("ShutdownHook") + static synchronized void initShutdownHook() { + if (shutdownHook == null) { + shutdownHook = + Executors.defaultThreadFactory() + .newThread( + new Runnable() { + @Override + public void run() { + shutdownHook = null; + shutdownThreadPools(); + } + }); + + try { + shutdownHook.setName("DelayedShutdownHook-iceberg"); + } catch (SecurityException e) { + LOG.warn("Cannot set thread name for the shutdown hook", e); + } + + try { + Runtime.getRuntime().addShutdownHook(shutdownHook); + } catch (SecurityException e) { + LOG.warn("Cannot install a shutdown hook for thread pools clean up", e); + } + } + } + + /** + * Stop the shutdown hook for the thread pools created via the {@link + * #newExitingWorkerPool(String, int)}. + * + * <p>Thread pools can still be stopped manually via the {@link #shutdownThreadPools()} method. + */ + @SuppressWarnings("ShutdownHook") + public static synchronized void removeShutdownHook() { + if (shutdownHook != null) { + try { + Runtime.getRuntime().removeShutdownHook(shutdownHook); + } catch (SecurityException e) { + LOG.warn("Cannot remove the shutdown hook for thread pools clean up", e); + } + shutdownHook = null; Review Comment: NIT newline after blocks (Iceberg style) -- This is an automated message from the Apache Git Service. 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