| /** |
| * 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 |
| * <p> |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * <p> |
| * 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.hadoop.hdds.server.events; |
| |
| import java.util.HashSet; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Set; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.function.Predicate; |
| import java.util.stream.Collectors; |
| |
| import org.apache.hadoop.metrics2.MetricsSystem; |
| import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem; |
| import org.apache.hadoop.ozone.lease.Lease; |
| import org.apache.hadoop.ozone.lease.LeaseAlreadyExistException; |
| import org.apache.hadoop.ozone.lease.LeaseExpiredException; |
| import org.apache.hadoop.ozone.lease.LeaseManager; |
| import org.apache.hadoop.ozone.lease.LeaseNotFoundException; |
| |
| import com.google.common.annotations.VisibleForTesting; |
| import com.google.common.base.Preconditions; |
| import org.apache.commons.collections.map.HashedMap; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Event watcher the (re)send a message after timeout. |
| * <p> |
| * Event watcher will send the tracked payload/event after a timeout period |
| * unless a confirmation from the original event (completion event) is arrived. |
| * |
| * @param <TIMEOUT_PAYLOAD> The type of the events which are tracked. |
| * @param <COMPLETION_PAYLOAD> The type of event which could cancel the |
| * tracking. |
| */ |
| @SuppressWarnings("CheckStyle") |
| public abstract class EventWatcher<TIMEOUT_PAYLOAD extends |
| IdentifiableEventPayload, |
| COMPLETION_PAYLOAD extends IdentifiableEventPayload> { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(EventWatcher.class); |
| |
| private final Event<TIMEOUT_PAYLOAD> startEvent; |
| |
| private final Event<COMPLETION_PAYLOAD> completionEvent; |
| |
| private final LeaseManager<Long> leaseManager; |
| |
| private final EventWatcherMetrics metrics; |
| |
| private final String name; |
| |
| private final Map<Long, TIMEOUT_PAYLOAD> trackedEventsByID = |
| new ConcurrentHashMap<>(); |
| |
| private final Set<TIMEOUT_PAYLOAD> trackedEvents = new HashSet<>(); |
| |
| private final Map<Long, Long> startTrackingTimes = new HashedMap(); |
| |
| public EventWatcher(String name, Event<TIMEOUT_PAYLOAD> startEvent, |
| Event<COMPLETION_PAYLOAD> completionEvent, |
| LeaseManager<Long> leaseManager) { |
| this.startEvent = startEvent; |
| this.completionEvent = completionEvent; |
| this.leaseManager = leaseManager; |
| this.metrics = new EventWatcherMetrics(); |
| Preconditions.checkNotNull(name); |
| if (name.equals("")) { |
| name = getClass().getSimpleName(); |
| } |
| if (name.equals("")) { |
| //for anonymous inner classes |
| name = getClass().getName(); |
| } |
| this.name = name; |
| } |
| |
| public EventWatcher(Event<TIMEOUT_PAYLOAD> startEvent, |
| Event<COMPLETION_PAYLOAD> completionEvent, |
| LeaseManager<Long> leaseManager) { |
| this("", startEvent, completionEvent, leaseManager); |
| } |
| |
| public void start(EventQueue queue) { |
| |
| queue.addHandler(startEvent, this::handleStartEvent); |
| |
| queue.addHandler(completionEvent, (completionPayload, publisher) -> { |
| try { |
| handleCompletion(completionPayload, publisher); |
| } catch (LeaseNotFoundException e) { |
| //It's already done. Too late, we already retried it. |
| //Not a real problem. |
| LOG.warn("Completion event without active lease. Id={}", |
| completionPayload.getId()); |
| } |
| }); |
| |
| MetricsSystem ms = DefaultMetricsSystem.instance(); |
| ms.register(name, "EventWatcher metrics", metrics); |
| } |
| |
| private synchronized void handleStartEvent(TIMEOUT_PAYLOAD payload, |
| EventPublisher publisher) { |
| metrics.incrementTrackedEvents(); |
| long identifier = payload.getId(); |
| startTrackingTimes.put(identifier, System.currentTimeMillis()); |
| |
| trackedEventsByID.put(identifier, payload); |
| trackedEvents.add(payload); |
| try { |
| Lease<Long> lease = leaseManager.acquire(identifier); |
| try { |
| lease.registerCallBack(() -> { |
| handleTimeout(publisher, identifier); |
| return null; |
| }); |
| |
| } catch (LeaseExpiredException e) { |
| handleTimeout(publisher, identifier); |
| } |
| } catch (LeaseAlreadyExistException e) { |
| //No problem at all. But timer is not reset. |
| } |
| } |
| |
| protected synchronized void handleCompletion(COMPLETION_PAYLOAD |
| completionPayload, EventPublisher publisher) throws |
| LeaseNotFoundException { |
| long id = completionPayload.getId(); |
| leaseManager.release(id); |
| TIMEOUT_PAYLOAD payload = trackedEventsByID.remove(id); |
| if (trackedEvents.remove(payload)) { |
| metrics.incrementCompletedEvents(); |
| long originalTime = startTrackingTimes.remove(id); |
| metrics.updateFinishingTime(System.currentTimeMillis() - originalTime); |
| onFinished(publisher, payload); |
| } |
| } |
| |
| private synchronized void handleTimeout(EventPublisher publisher, |
| long identifier) { |
| metrics.incrementTimedOutEvents(); |
| TIMEOUT_PAYLOAD payload = trackedEventsByID.remove(identifier); |
| trackedEvents.remove(payload); |
| startTrackingTimes.remove(payload.getId()); |
| onTimeout(publisher, payload); |
| } |
| |
| |
| /** |
| * Check if a specific payload is in-progress. |
| */ |
| public synchronized boolean contains(TIMEOUT_PAYLOAD payload) { |
| return trackedEvents.contains(payload); |
| } |
| |
| public synchronized boolean remove(TIMEOUT_PAYLOAD payload) { |
| try { |
| leaseManager.release(payload.getId()); |
| } catch (LeaseNotFoundException e) { |
| LOG.warn("Completion event without active lease. Id={}", |
| payload.getId()); |
| } |
| trackedEventsByID.remove(payload.getId()); |
| return trackedEvents.remove(payload); |
| |
| } |
| |
| protected abstract void onTimeout( |
| EventPublisher publisher, TIMEOUT_PAYLOAD payload); |
| |
| protected abstract void onFinished( |
| EventPublisher publisher, TIMEOUT_PAYLOAD payload); |
| |
| public List<TIMEOUT_PAYLOAD> getTimeoutEvents( |
| Predicate<? super TIMEOUT_PAYLOAD> predicate) { |
| return trackedEventsByID.values().stream().filter(predicate) |
| .collect(Collectors.toList()); |
| } |
| |
| @VisibleForTesting |
| protected EventWatcherMetrics getMetrics() { |
| return metrics; |
| } |
| |
| /** |
| * Returns a tracked event to which the specified id is |
| * mapped, or {@code null} if there is no mapping for the id. |
| */ |
| public TIMEOUT_PAYLOAD getTrackedEventbyId(long id) { |
| return trackedEventsByID.get(id); |
| } |
| |
| public Map<Long, TIMEOUT_PAYLOAD> getTrackedEventsByID() { |
| return trackedEventsByID; |
| } |
| |
| public Set<TIMEOUT_PAYLOAD> getTrackedEvents() { |
| return trackedEvents; |
| } |
| } |