poorbarcode commented on code in PR #24833: URL: https://github.com/apache/pulsar/pull/24833#discussion_r2476945471
########## pulsar-common/src/main/java/org/apache/pulsar/common/semaphore/AsyncSemaphoreImpl.java: ########## @@ -0,0 +1,330 @@ +/* + * 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.common.semaphore; + +import io.netty.util.concurrent.DefaultThreadFactory; +import java.util.Queue; +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.Executors; +import java.util.concurrent.LinkedBlockingQueue; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.ScheduledFuture; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicLong; +import java.util.concurrent.atomic.AtomicLongFieldUpdater; +import java.util.function.BooleanSupplier; +import java.util.function.LongConsumer; +import org.apache.pulsar.common.util.Runnables; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Implementation of AsyncSemaphore with timeout and queue size limits. + */ +public class AsyncSemaphoreImpl implements AsyncSemaphore, AutoCloseable { + private static final Logger log = LoggerFactory.getLogger(AsyncSemaphoreImpl.class); + + private final AtomicLong availablePermits; + private final Queue<PendingRequest> queue; + private final long maxPermits; + private final long timeoutMillis; + private final ScheduledExecutorService executor; + private final boolean shutdownExecutor; + private final LongConsumer queueLatencyRecorder; + private final AtomicBoolean closed = new AtomicBoolean(false); + private final Runnable processQueueRunnable = Runnables.catchingAndLoggingThrowables(this::internalProcessQueue); + + /** + * Creates an AsyncSemaphoreImpl with the given parameters. + * @param maxPermits max number of permits available for acquisition, set to <= 0 for unbounded semaphore (not + * recommended) + * @param maxQueueSize max number of requests that can be queued, set to <= 0 for unbounded queue (not recommended) + * @param timeoutMillis timeout in milliseconds for acquiring permits + */ + public AsyncSemaphoreImpl(long maxPermits, int maxQueueSize, long timeoutMillis) { + this(maxPermits, maxQueueSize, timeoutMillis, maxPermits > 0 ? createExecutor() : null, maxPermits > 0, null); + } + + /** + * Creates an AsyncSemaphoreImpl with the given parameters. + * @param maxPermits max number of permits available for acquisition, set to <= 0 for unbounded semaphore (not + * recommended) + * @param maxQueueSize max number of requests that can be queued, set to <= 0 for unbounded queue (not recommended) + * @param timeoutMillis timeout in milliseconds for acquiring permits + * @param executor executor service to use for scheduling timeouts, it is expected to be single threaded + * @param queueLatencyRecorder consumer to record queue latency, Long.MAX_VALUE is used for requests that timed out + */ + public AsyncSemaphoreImpl(long maxPermits, int maxQueueSize, long timeoutMillis, + ScheduledExecutorService executor, LongConsumer queueLatencyRecorder) { + this(maxPermits, maxQueueSize, timeoutMillis, executor, false, queueLatencyRecorder); + } + + AsyncSemaphoreImpl(long maxPermits, int maxQueueSize, long timeoutMillis, ScheduledExecutorService executor, + boolean shutdownExecutor, LongConsumer queueLatencyRecorder) { + this.availablePermits = new AtomicLong(maxPermits); + this.maxPermits = maxPermits; + this.queue = maxQueueSize > 0 ? new ArrayBlockingQueue<>(maxQueueSize) : new LinkedBlockingQueue<>(); + this.timeoutMillis = timeoutMillis; + this.executor = executor; + this.shutdownExecutor = shutdownExecutor; + this.queueLatencyRecorder = queueLatencyRecorder; + } + + private static ScheduledExecutorService createExecutor() { + return Executors.newSingleThreadScheduledExecutor( + new DefaultThreadFactory("async-semaphore-executor")); + } + + @Override + public CompletableFuture<AsyncSemaphorePermit> acquire(long permits, BooleanSupplier isCancelled) { + return internalAcquire(permits, permits, isCancelled); + } + + private CompletableFuture<AsyncSemaphorePermit> internalAcquire(long permits, long acquirePermits, + BooleanSupplier isCancelled) { + validatePermits(permits); + + // if maximum permits is <= 0, then the semaphore is unbounded + if (isUnbounded()) { + return CompletableFuture.completedFuture(new SemaphorePermit(permits)); + } + + CompletableFuture<AsyncSemaphorePermit> future = new CompletableFuture<>(); + + if (closed.get()) { + future.completeExceptionally(new PermitAcquireAlreadyClosedException("Semaphore is closed")); + return future; + } + + PendingRequest request = new PendingRequest(permits, acquirePermits, future, isCancelled); + if (!queue.offer(request)) { + future.completeExceptionally(new PermitAcquireQueueFullException( + "Semaphore queue is full")); + return future; + } + // Schedule timeout + ScheduledFuture<?> timeoutTask = executor.schedule(() -> { + if (!request.future.isDone() && queue.remove(request)) { + // timeout is recorded with Long.MAX_VALUE as the age + recordQueueLatency(Long.MAX_VALUE); + // also record the time in the queue + recordQueueLatency(request.getAgeNanos()); + future.completeExceptionally(new PermitAcquireTimeoutException( + "Permit acquisition timed out")); + // the next request might have smaller permits and that might be processed + processQueue(); + } + }, timeoutMillis, TimeUnit.MILLISECONDS); + request.setTimeoutTask(timeoutTask); + + processQueue(); + return future; + } + + private void validatePermits(long permits) { + if (permits < 0) { + throw new IllegalArgumentException("Invalid negative permits value: " + permits); + } + if (!isUnbounded() && permits > maxPermits) { + throw new IllegalArgumentException( + "Requested permits=" + permits + " is larger than maxPermits=" + maxPermits); + } + } + + private boolean isUnbounded() { + return maxPermits <= 0; + } + + private void recordQueueLatency(long ageNanos) { + if (queueLatencyRecorder != null) { + queueLatencyRecorder.accept(ageNanos); + } + } + + @Override + public CompletableFuture<AsyncSemaphorePermit> update(AsyncSemaphorePermit permit, long newPermits, + BooleanSupplier isCancelled) { + validatePermits(newPermits); + if (isUnbounded()) { + return CompletableFuture.completedFuture(new SemaphorePermit(newPermits)); Review Comment: https://github.com/apache/pulsar/pull/24833/files#r2476939392 The same bug will happen here -- This is an automated message from the Apache Git Service. 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