/**
* Licensed to Cloudera, Inc. under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Cloudera, Inc. 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 com.cloudera.flume.master;
import java.io.IOException;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.cloudera.distributed.GossipMulticast;
import com.cloudera.distributed.Group;
import com.cloudera.distributed.MessageReceiver;
import com.cloudera.distributed.TCPNodeId;
import com.cloudera.distributed.GossipMulticast.GossipMessage;
import com.cloudera.flume.conf.FlumeConfiguration;
import com.cloudera.util.Pair;
/**
* An implementation of an AckManager that uses Gossip to send acknowledgements
* to other servers.
*/
public class GossipedMasterAckManager extends MasterAckManager implements
MessageReceiver<GossipMulticast.GossipMessage> {
static final Logger LOG = LoggerFactory
.getLogger(GossipedMasterAckManager.class);
GossipMulticast gossip;
final Group group;
final int port;
GossipedMasterAckManager(FlumeConfiguration conf) {
this(conf.getConfigMasterGossipHostsList(), conf.getMasterGossipPort(),
conf.getMasterGossipMaxAgeMs());
}
GossipedMasterAckManager(List<Pair<String, Integer>> peers, int port,
long maxAgeMs) {
group = new Group();
for (Pair<String, Integer> p : peers) {
group.addNode(new TCPNodeId(p.getLeft(), p.getRight()));
}
this.port = port;
// TODO(henry) choose the interface from config
gossip = new GossipMulticast(group, new TCPNodeId("0.0.0.0", port),
maxAgeMs);
}
/**
* Start the underlying gossip server (and throw an exception if it fails)
*/
synchronized public void start() throws IOException {
gossip.registerReceiver(this);
gossip.start();
}
/**
* Stop the underlying gossip server
*/
synchronized public void stop() {
try {
gossip.stop();
} catch (InterruptedException e) {
LOG.warn("Gossip interrupted while stopping in GossipedAckManager", e);
}
}
synchronized public void acknowledge(String ackid) {
super.acknowledge(ackid);
gossip.sendToGroup(group, ackid.getBytes());
}
@Override
synchronized public void receiveMessage(GossipMessage msg) {
String ackid = new String(msg.getContents());
LOG.info("Received ACK at " + port + " from gossip " + ackid);
super.acknowledge(new String(msg.getContents()));
}
}