| /* |
| * 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.sling.distribution.journal.impl.publisher; |
| |
| import static org.apache.sling.distribution.journal.HandlerAdapter.create; |
| import static org.apache.sling.commons.scheduler.Scheduler.PROPERTY_SCHEDULER_CONCURRENT; |
| import static org.apache.sling.commons.scheduler.Scheduler.PROPERTY_SCHEDULER_PERIOD; |
| |
| import java.io.Closeable; |
| import java.util.Dictionary; |
| import java.util.Hashtable; |
| |
| import javax.annotation.ParametersAreNonnullByDefault; |
| |
| import org.apache.sling.distribution.journal.impl.shared.Topics; |
| import org.apache.sling.distribution.journal.messages.Messages; |
| import org.apache.sling.distribution.journal.messages.Messages.SubscriberConfiguration; |
| import org.apache.commons.io.IOUtils; |
| import org.osgi.framework.BundleContext; |
| import org.osgi.framework.ServiceRegistration; |
| import org.osgi.service.component.annotations.Activate; |
| import org.osgi.service.component.annotations.Component; |
| import org.osgi.service.component.annotations.Deactivate; |
| import org.osgi.service.component.annotations.Reference; |
| |
| import org.apache.sling.distribution.journal.messages.Messages.DiscoveryMessage; |
| import org.apache.sling.distribution.journal.MessageHandler; |
| import org.apache.sling.distribution.journal.MessageInfo; |
| import org.apache.sling.distribution.journal.MessagingProvider; |
| import org.apache.sling.distribution.journal.JournalAvailable; |
| import org.apache.sling.distribution.journal.Reset; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Listens for discovery messages and tracks presence of Subscribers as well as |
| * the last processed offset of each Subscriber |
| * |
| * This component uses lazy starting so it is only started when there is at least one Agent |
| * that requires it. |
| * |
| * This component is meant to be shared by Publisher agents. |
| */ |
| @Component(service = DiscoveryService.class) |
| @ParametersAreNonnullByDefault |
| public class DiscoveryService implements Runnable { |
| |
| private static final Logger LOG = LoggerFactory.getLogger(DiscoveryService.class); |
| |
| private static final long REFRESH_TTL_MS = 30000; |
| |
| @Reference |
| JournalAvailable journalAvailable; |
| |
| @Reference |
| private MessagingProvider messagingProvider; |
| |
| @Reference |
| private Topics topics; |
| |
| @Reference |
| private TopologyChangeHandler topologyChangeHandler; |
| |
| private volatile ServiceRegistration<?> reg; |
| |
| private final TopologyViewManager viewManager = new TopologyViewManager(REFRESH_TTL_MS); |
| |
| private Closeable poller; |
| |
| public DiscoveryService() { |
| } |
| |
| public DiscoveryService( |
| MessagingProvider messagingProvider, |
| TopologyChangeHandler topologyChangeHandler, |
| Topics topics) { |
| this.messagingProvider = messagingProvider; |
| this.topologyChangeHandler = topologyChangeHandler; |
| this.topics = topics; |
| } |
| |
| @Activate |
| public void activate(BundleContext context) { |
| poller = messagingProvider.createPoller( |
| topics.getDiscoveryTopic(), |
| Reset.latest, |
| create(Messages.DiscoveryMessage.class, new DiscoveryMessageHandler())); |
| startTopologyViewUpdaterTask(context); |
| LOG.info("Discovery service started"); |
| } |
| |
| @Deactivate |
| public void deactivate() { |
| if (reg != null) { |
| reg.unregister(); |
| } |
| IOUtils.closeQuietly(poller); |
| LOG.info("Discovery service stopped"); |
| } |
| |
| public TopologyView getTopologyView() { |
| return viewManager.getCurrentView(); |
| } |
| |
| @Override |
| public void run() { |
| TopologyView oldView = viewManager.updateView(); |
| TopologyView newView = viewManager.getCurrentView(); |
| if (! newView.equals(oldView)) { |
| LOG.info("TopologyView changed from {} to {}", oldView, newView); |
| topologyChangeHandler.changed(oldView, newView); |
| } |
| } |
| |
| private void startTopologyViewUpdaterTask(BundleContext context) { |
| // Register periodic task to update the topology view |
| Dictionary<String, Object> props = new Hashtable<>(); |
| props.put(PROPERTY_SCHEDULER_CONCURRENT, false); |
| props.put(PROPERTY_SCHEDULER_PERIOD, 5L); // every 5 seconds |
| reg = context.registerService(Runnable.class.getName(), this, props); |
| } |
| |
| private final class DiscoveryMessageHandler implements MessageHandler<DiscoveryMessage> { |
| |
| @Override |
| public void handle(MessageInfo info, DiscoveryMessage disMsg) { |
| |
| long now = System.currentTimeMillis(); |
| AgentId subAgentId = new AgentId(disMsg.getSubSlingId(), disMsg.getSubAgentName()); |
| |
| for (Messages.SubscriberState subStateMsg : disMsg.getSubscriberStateList()) { |
| SubscriberConfiguration subConfig = disMsg.getSubscriberConfiguration(); |
| State subState = new State(subStateMsg.getPubAgentName(), subAgentId.getAgentId(), now, subStateMsg.getOffset(), subStateMsg.getRetries(), subConfig.getMaxRetries(), subConfig.getEditable()); |
| viewManager.refreshState(subState); |
| } |
| } |
| } |
| } |