gnodet-bot commented on code in PR #29489: URL: https://github.com/apache/camel/pull/29489#discussion_r4541104148
########## components/camel-azure/camel-azure-iothub/src/main/java/org/apache/camel/component/azure/iothub/client/DeviceClientPool.java: ########## @@ -0,0 +1,602 @@ +/* + * 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.component.azure.iothub.client; + +import java.time.Duration; +import java.util.Map; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.Executors; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicBoolean; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.atomic.AtomicReference; +import java.util.function.LongSupplier; + +import com.microsoft.azure.sdk.iot.device.ConnectionStatusChangeContext; +import com.microsoft.azure.sdk.iot.device.DeviceClient; +import com.microsoft.azure.sdk.iot.device.IotHubClientProtocol; +import com.microsoft.azure.sdk.iot.device.IotHubConnectionStatusChangeReason; +import com.microsoft.azure.sdk.iot.device.transport.IotHubConnectionStatus; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Thread-safe pool of Azure IoT Hub {@link DeviceClient} instances, keyed by the resolved hub/device/module identity + * derived from the connection string instead of only the raw device id. + * + * <p> + * Clients are created lazily, reused across messages, and evicted after an idle timeout. Connection status changes are + * monitored through the Azure SDK callback, and disconnected clients are retired automatically; any in-use client is + * closed only when the final lease is released. Callers may also remove a client from the pool explicitly during + * cleanup. + * </p> + */ +public class DeviceClientPool { + + private static final Logger LOG = LoggerFactory.getLogger(DeviceClientPool.class); + + @FunctionalInterface + public interface DeviceClientFactory { + DeviceClient create(String connectionString, IotHubClientProtocol protocol) throws Exception; + } + + private static final class PooledClient { + final DeviceClient client; + volatile long lastUsed; + final AtomicInteger inUse = new AtomicInteger(); + volatile boolean retired; + final AtomicBoolean closed = new AtomicBoolean(); + + PooledClient(DeviceClient client, long nowMillis) { + this.client = client; + this.lastUsed = nowMillis; + } + + void touch(long nowMillis) { + this.lastUsed = nowMillis; + } + + void acquire() { + inUse.incrementAndGet(); + } + + boolean release() { + return inUse.decrementAndGet() == 0; + } + } + + public static final class Lease implements AutoCloseable { + private final DeviceClientPool pool; + private final String poolKey; + private final PooledClient pooled; + private boolean closed; + + private Lease(DeviceClientPool pool, String poolKey, PooledClient pooled) { + this.pool = pool; + this.poolKey = poolKey; + this.pooled = pooled; + } + + public DeviceClient getClient() { + return pooled.client; + } + + public DeviceClient client() { + return getClient(); + } + + @Override + public void close() { + if (closed) { + return; + } + closed = true; + if (pooled.release()) { + if (pooled.retired) { + pool.closeRetired(pooled); + } else { + pool.touchAndMaybeEvict(poolKey); + } + } + } + } + + private final Duration idleTimeout; + private final Duration evictionInterval; + private final Map<String, PooledClient> pool = new ConcurrentHashMap<>(); + private final Map<String, CompletableFuture<DeviceClient>> creationFutures = new ConcurrentHashMap<>(); + private final AtomicBoolean shuttingDown = new AtomicBoolean(false); + + private DeviceClientFactory deviceClientFactory = DeviceClient::new; + private LongSupplier nowMillisSupplier = System::currentTimeMillis; + private volatile ScheduledExecutorService evictionExecutor; + private final AtomicBoolean started = new AtomicBoolean(false); + + public DeviceClientPool(Duration idleTimeout, Duration evictionInterval) { + this(idleTimeout, evictionInterval, null); + } + + public DeviceClientPool(Duration idleTimeout, Duration evictionInterval, ScheduledExecutorService evictionExecutor) { + this.idleTimeout = isPositive(idleTimeout) ? idleTimeout : Duration.ofMinutes(5); + this.evictionInterval = isPositive(evictionInterval) ? evictionInterval : Duration.ofSeconds(30); + this.evictionExecutor = evictionExecutor; + } + + private static boolean isPositive(Duration d) { + return d != null && !d.isZero() && !d.isNegative(); + } + + private ScheduledExecutorService getOrCreateEvictionExecutor() { + ScheduledExecutorService executor = evictionExecutor; + if (executor != null) { + return executor; + } + synchronized (this) { + executor = evictionExecutor; + if (executor == null) { + executor = Executors.newSingleThreadScheduledExecutor(r -> { + Thread t = new Thread(r, "camel-azure-iothub-device-client-evictor"); + t.setDaemon(true); + return t; + }); + evictionExecutor = executor; + } + return executor; + } + } + + public void start() { + if (!started.compareAndSet(false, true)) { + return; + } + ScheduledExecutorService executor = getOrCreateEvictionExecutor(); + executor.scheduleAtFixedRate(this::evictIdleClients, + evictionInterval.toMillis(), evictionInterval.toMillis(), TimeUnit.MILLISECONDS); + LOG.info("DeviceClient eviction enabled. idleTimeout={}s, interval={}s", + idleTimeout.getSeconds(), evictionInterval.getSeconds()); + } + + // package-private for test hooks only + DeviceClient getOrCreate(String deviceId, String connectionString, IotHubClientProtocol protocol) { + if (Thread.currentThread().isInterrupted() || shuttingDown.get()) { + throw new IllegalStateException("Skipping client creation due to shutdown: " + deviceId); + } + + String poolKey = resolvePoolKey(deviceId, connectionString); + final long now = nowMillisSupplier.getAsLong(); + + PooledClient existing = pool.get(poolKey); + if (existing != null) { + existing.touch(now); + return existing.client; + } + + CompletableFuture<DeviceClient> createdFuture = new CompletableFuture<>(); + CompletableFuture<DeviceClient> inFlight = creationFutures.putIfAbsent(poolKey, createdFuture); + if (inFlight == null) { + try { + PooledClient rechecked = pool.get(poolKey); + if (rechecked != null) { + createdFuture.complete(rechecked.client); + return rechecked.client; + } + DeviceClient client = createClient(deviceId, connectionString, protocol); + PooledClient pooled = new PooledClient(client, now); + PooledClient previous = pool.putIfAbsent(poolKey, pooled); + if (previous != null) { + client.close(); + previous.touch(now); + createdFuture.complete(previous.client); + return previous.client; + } + if (shuttingDown.get()) { + pool.remove(poolKey, pooled); + closeQuietly(deviceId, client, "shutdown after creation"); + throw new IllegalStateException("Skipping client creation due to shutdown: " + deviceId); + } + createdFuture.complete(client); + return client; + } catch (Throwable e) { + if (!createdFuture.isDone()) { + createdFuture.completeExceptionally(e); + } + throw e; + } finally { + creationFutures.remove(poolKey, createdFuture); + if (!createdFuture.isDone()) { + createdFuture.completeExceptionally( + new IllegalStateException("DeviceClient creation failed for device: " + deviceId)); + } + } + } + + try { + return inFlight.get(); + } catch (InterruptedException e) { + Thread.currentThread().interrupt(); + throw new IllegalStateException("Interrupted while waiting for DeviceClient creation for device: " + deviceId, e); + } catch (ExecutionException e) { + Throwable cause = e.getCause(); + if (cause instanceof RuntimeException re) { + throw re; + } + if (cause instanceof Error err) { + throw err; + } + throw new RuntimeException("DeviceClient creation failed for device: " + deviceId, cause); + } + } + + public Lease acquire(String deviceId, String connectionString, IotHubClientProtocol protocol) { + if (Thread.currentThread().isInterrupted() || shuttingDown.get()) { + throw new IllegalStateException("Skipping client creation due to shutdown: " + deviceId); + } + + String poolKey = resolvePoolKey(deviceId, connectionString); + final long now = nowMillisSupplier.getAsLong(); + + for (;;) { + AtomicReference<PooledClient> evicted = new AtomicReference<>(); + PooledClient existing = pool.computeIfPresent(poolKey, (key, pooled) -> { + if (pooled.inUse.get() > 0) { + pooled.touch(now); + pooled.acquire(); + return pooled; + } + if ((now - pooled.lastUsed) > idleTimeout.toMillis()) { + evicted.set(pooled); + return null; + } + pooled.touch(now); + pooled.acquire(); + return pooled; + }); + if (existing != null) { + return new Lease(this, poolKey, existing); + } + if (evicted.get() != null) { + closeQuietly(poolKey, evicted.get().client, "idle eviction"); + continue; + } + + DeviceClient client = getOrCreate(deviceId, connectionString, protocol); + AtomicReference<PooledClient> acquired = new AtomicReference<>(); + pool.computeIfPresent(poolKey, (key, pooled) -> { + if (pooled.client != client) { + return pooled; + } + pooled.touch(now); + pooled.acquire(); + acquired.set(pooled); + return pooled; + }); + if (acquired.get() != null) { + return new Lease(this, poolKey, acquired.get()); + } + // The pool entry may have been evicted or replaced between creation and the acquire step. + // Loop back to retry instead of recursing to keep the stack depth constant. + continue; + } + } + + public Lease lease(String deviceId, String connectionString, IotHubClientProtocol protocol) { + return acquire(deviceId, connectionString, protocol); + } + + private boolean isCreationInProgress(String poolKey) { + return creationFutures.containsKey(poolKey); + } + + private boolean isCreationInProgressForDevice(String deviceId) { + if (deviceId == null || deviceId.isBlank()) { + return false; + } + for (String poolKey : creationFutures.keySet()) { + if (matchesDeviceId(poolKey, deviceId)) { + return true; + } + } + return false; + } + + void remove(String deviceId, String connectionString) { + removePoolEntry(resolvePoolKey(deviceId, connectionString)); + } + + void remove(String deviceId) { + if (deviceId == null || deviceId.isBlank()) { + return; + } + if (isCreationInProgressForDevice(deviceId)) { + LOG.debug("Skipping removal of in-flight DeviceClient for device {} while creation is still in progress", deviceId); + return; + } + + String directKey = deviceId; + PooledClient pooled = pool.remove(directKey); + if (pooled != null) { + closeQuietly(deviceId, pooled.client, "explicit removal"); + return; + } + + for (Map.Entry<String, PooledClient> entry : pool.entrySet()) { + String key = entry.getKey(); + if (matchesDeviceId(key, deviceId)) { + if (pool.remove(key, entry.getValue())) { + closeQuietly(deviceId, entry.getValue().client, "explicit removal"); + return; + } + } + } + } + + private void removePoolEntry(String poolKey) { + if (poolKey == null || poolKey.isBlank()) { + return; + } + if (isCreationInProgress(poolKey)) { + LOG.debug("Skipping removal of in-flight DeviceClient for device {} while creation is still in progress", poolKey); + return; + } + PooledClient pooled = pool.remove(poolKey); + if (pooled != null) { + closeQuietly(poolKey, pooled.client, "explicit removal"); + } + } + + private static boolean matchesDeviceId(String poolKey, String deviceId) { + if (poolKey == null) { + return false; + } + if (poolKey.equals(deviceId)) { + return true; + } + String[] parts = poolKey.split(":"); + return parts.length >= 2 && parts[1].equals(deviceId); + } + + private static String resolvePoolKey(String deviceId, String connectionString) { + if (deviceId == null || deviceId.isBlank()) { + return connectionString; + } + String[] items = connectionString == null ? new String[0] : connectionString.split(";"); + String hostName = null; + String csDeviceId = null; + String moduleId = null; + for (String item : items) { + if (item == null || item.isBlank()) { + continue; + } + int eq = item.indexOf('='); + if (eq <= 0) { + continue; + } + String key = item.substring(0, eq).trim(); + String value = item.substring(eq + 1).trim(); + switch (key) { + case "HostName" -> hostName = value; + case "DeviceId" -> csDeviceId = value; + case "ModuleId" -> moduleId = value; + default -> { + // ignore other connection-string fields + } + } + } + if (csDeviceId != null && !csDeviceId.equals(deviceId)) { + throw new IllegalArgumentException( + "Device id '" + deviceId + "' does not match the connection string's DeviceId '" + csDeviceId + "'"); + } + StringBuilder identity = new StringBuilder(); + if (hostName != null && !hostName.isBlank()) { + identity.append(hostName); + } + if (csDeviceId != null && !csDeviceId.isBlank()) { + if (!identity.isEmpty()) { + identity.append(':'); + } + identity.append(csDeviceId); + } + if (moduleId != null && !moduleId.isBlank()) { + if (!identity.isEmpty()) { + identity.append(':'); + } + identity.append(moduleId); + } + return !identity.isEmpty() ? identity.toString() : deviceId; + } + + private DeviceClient createClient(String deviceId, String connectionString, IotHubClientProtocol protocol) { + try { + DeviceClient client = deviceClientFactory.create(connectionString, protocol); + if (shuttingDown.get()) { + closeQuietly(deviceId, client, "shutdown while creating"); + throw new IllegalStateException("Skipping client creation due to shutdown: " + deviceId); + } + client.open(true); + if (shuttingDown.get()) { + closeQuietly(deviceId, client, "shutdown after open"); + throw new IllegalStateException("Skipping client creation due to shutdown: " + deviceId); + } + try { + // Avoid duplicate desired-property subscriptions: subscribe only if not already subscribed. + // The Azure DeviceClient does not expose a way to check, so we rely on only subscribing once per client creation. + client.subscribeToDesiredProperties((twinUpdate, ctx) -> { + }, null); + client.setConnectionStatusChangeCallback(context -> { + if (context == null) { + return; + } + evictDisconnectedClient(deviceId, connectionString, client, context); + }, null); + } catch (Exception e) { + closeQuietly(deviceId, client, "subscription setup"); + throw e; + } + LOG.debug("Created new DeviceClient for device: {}", deviceId); + return client; + } catch (Exception e) { + if (isShutdownInterruption(e)) { + Thread.currentThread().interrupt(); + LOG.warn("DeviceClient creation interrupted due to shutdown for device: {}", deviceId); + throw new IllegalStateException("DeviceClient creation interrupted for device: " + deviceId, e); + } + throw new RuntimeException("DeviceClient creation failed for device: " + deviceId, e); + } + } + + private void evictDisconnectedClient( + String deviceId, String connectionString, DeviceClient client, + ConnectionStatusChangeContext context) { + if (context == null || shuttingDown.get()) { + return; + } + if (context.getNewStatus() != IotHubConnectionStatus.DISCONNECTED) { + return; + } + if (context.getNewStatusReason() == IotHubConnectionStatusChangeReason.CLIENT_CLOSE) { + return; + } + + String poolKey = resolvePoolKey(deviceId, connectionString); + + AtomicReference<PooledClient> removed = new AtomicReference<>(); + pool.computeIfPresent(poolKey, (key, pooled) -> { + if (pooled.client != client) { + return pooled; + } + pooled.retired = true; + removed.set(pooled); + return null; + }); + + PooledClient retired = removed.get(); + if (retired != null) { + LOG.warn("Evicted DeviceClient for device {} after disconnect. previousStatus={}, reason={}, cause={}", + deviceId, context.getPreviousStatus(), context.getNewStatusReason(), context.getCause()); + if (retired.inUse.get() == 0) { + closeRetired(retired); + } + } + } + + private void touchAndMaybeEvict(String poolKey) { + long now = nowMillisSupplier.getAsLong(); + AtomicReference<PooledClient> retired = new AtomicReference<>(); + pool.computeIfPresent(poolKey, (key, current) -> { + if (current.inUse.get() > 0) { + current.touch(now); + return current; + } + if ((now - current.lastUsed) > idleTimeout.toMillis()) { + current.retired = true; + retired.set(current); + return null; + } + current.touch(now); + return current; + }); + PooledClient expired = retired.get(); + if (expired != null) { + closeRetired(expired); + } + } + + private void closeRetired(PooledClient pooled) { + if (pooled.closed.compareAndSet(false, true)) { + ScheduledExecutorService executor = getOrCreateEvictionExecutor(); + executor.execute(() -> closeQuietly("retired", pooled.client, "retired eviction")); + } + } Review Comment: 🚨 **`RejectedExecutionException` after `shutdown()`** `getOrCreateEvictionExecutor()` returns the already-constructed executor via the volatile read (shutdown does not null the field, only calls `shutdownNow()`). `executor.execute()` on a shut-down executor throws `RejectedExecutionException`, which propagates uncaught from `Lease.close()` and from the disconnect callback. ```suggestion private void closeRetired(PooledClient pooled) { if (pooled.closed.compareAndSet(false, true)) { ScheduledExecutorService executor = evictionExecutor; if (executor != null && !executor.isShutdown()) { try { executor.execute(() -> closeQuietly("retired", pooled.client, "retired eviction")); return; } catch (RejectedExecutionException ignored) { // fall through to synchronous close if the executor was shut down concurrently } } closeQuietly("retired", pooled.client, "retired eviction"); } } ``` -- This is an automated message from the Apache Git Service. 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