src/main/java/org/apache/sling/distribution/journal/impl/publisher/PackageDistributedNotifier.java

/*
 * 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 java.util.Objects;
import java.util.function.Supplier;
import java.util.stream.LongStream;

import javax.annotation.ParametersAreNonnullByDefault;

import org.apache.sling.distribution.journal.impl.event.DistributionEvent;
import org.apache.sling.distribution.journal.impl.queue.OffsetQueue;
import org.apache.sling.distribution.journal.impl.queue.QueueItemFactory;
import org.apache.sling.distribution.journal.impl.queue.impl.PubQueueCacheService;
import org.apache.sling.distribution.journal.impl.shared.Topics;
import org.apache.sling.distribution.journal.messages.PackageDistributedMessage;
import org.apache.sling.distribution.journal.JsonMessageSender;
import org.apache.sling.distribution.journal.MessagingProvider;

import org.apache.commons.lang3.StringUtils;
import org.apache.sling.distribution.queue.DistributionQueueItem;
import org.osgi.service.component.annotations.Activate;
import org.osgi.service.component.annotations.Component;
import org.osgi.service.component.annotations.Reference;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventAdmin;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static org.apache.sling.distribution.packaging.DistributionPackageInfo.PROPERTY_REQUEST_DEEP_PATHS;
import static org.apache.sling.distribution.packaging.DistributionPackageInfo.PROPERTY_REQUEST_PATHS;

@Component(immediate = true)
@ParametersAreNonnullByDefault
public class PackageDistributedNotifier implements TopologyChangeHandler {

    private static final Logger LOG = LoggerFactory.getLogger(PackageDistributedNotifier.class);

    @Reference
    private EventAdmin eventAdmin;

    @Reference
    private PubQueueCacheService pubQueueCacheService;

    @Reference
    private MessagingProvider messagingProvider;

    @Reference
    private Topics topics;

    private JsonMessageSender<PackageDistributedMessage> sender;

    private boolean sendMsg;

    @Activate
    public void activate() {
        sendMsg = StringUtils.isNotBlank(topics.getEventTopic());
        if (sendMsg) {
            sender = messagingProvider.createJsonSender();
        }
        LOG.info("Started package distributed notifier with event message topic {}", topics.getEventTopic());
    }

    @Override
    public void changed(TopologyView oldView, TopologyView newView) {
        TopologyViewDiff diffView = new TopologyViewDiff(oldView, newView);
        diffView.getProcessedOffsets().forEach(this::processOffsets);
    }

    /**
     * @param  pubAgentName the name of the publisher agent
     * @param offsets range of offsets, from smallest offset to largest offset.
     */
    private void processOffsets(String pubAgentName, Supplier<LongStream> offsets) {
        long minOffset = offsets.get().findFirst().getAsLong();
        OffsetQueue<DistributionQueueItem> offsetQueue = pubQueueCacheService.getOffsetQueue(pubAgentName, minOffset);
        offsets
        	.get()
        	.mapToObj(offsetQueue::getItem)
        	.filter(Objects::nonNull)
        	.forEach(msg -> processOffset(pubAgentName, msg));
    }

    protected void processOffset(String pubAgentName, DistributionQueueItem queueItem) {
        sendEvt(pubAgentName, queueItem);
        sendMsg(pubAgentName, queueItem);
    }

    private void sendMsg(String pubAgentName, DistributionQueueItem queueItem) {
        if (sendMsg) {
            PackageDistributedMessage msg = new PackageDistributedMessage();
            msg.pubAgentName = pubAgentName;
            msg.packageId = queueItem.getPackageId();
            msg.offset = (Long) queueItem.get(QueueItemFactory.RECORD_OFFSET);
            msg.paths = (String[]) queueItem.get(PROPERTY_REQUEST_PATHS);
            msg.deepPaths = (String[]) queueItem.get(PROPERTY_REQUEST_DEEP_PATHS);

            sender.send(topics.getEventTopic(), msg);
        }
    }

    private void sendEvt(String pubAgentName, DistributionQueueItem queueItem) {
        Event distributed = DistributionEvent.eventPackageDistributed(queueItem, pubAgentName);
        eventAdmin.sendEvent(distributed);
    }
}