/**
* 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.flume.node;
import java.io.IOException;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.cache.ChildData;
import org.apache.curator.framework.recipes.cache.NodeCache;
import org.apache.curator.framework.recipes.cache.NodeCacheListener;
import org.apache.flume.FlumeException;
import org.apache.flume.conf.FlumeConfiguration;
import org.apache.flume.lifecycle.LifecycleAware;
import org.apache.flume.lifecycle.LifecycleState;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.eventbus.EventBus;
public class PollingZooKeeperConfigurationProvider extends
AbstractZooKeeperConfigurationProvider implements LifecycleAware {
private static final Logger LOGGER = LoggerFactory
.getLogger(PollingZooKeeperConfigurationProvider.class);
private final EventBus eventBus;
private final CuratorFramework client;
private NodeCache agentNodeCache;
private FlumeConfiguration flumeConfiguration;
private LifecycleState lifecycleState;
public PollingZooKeeperConfigurationProvider(String agentName,
String zkConnString, String basePath, EventBus eventBus) {
super(agentName, zkConnString, basePath);
this.eventBus = eventBus;
client = createClient();
agentNodeCache = null;
flumeConfiguration = null;
lifecycleState = LifecycleState.IDLE;
}
@Override
protected FlumeConfiguration getFlumeConfiguration() {
return flumeConfiguration;
}
@Override
public void start() {
LOGGER.debug("Starting...");
try {
client.start();
try {
agentNodeCache = new NodeCache(client, basePath + "/" + getAgentName());
agentNodeCache.start();
agentNodeCache.getListenable().addListener(new NodeCacheListener() {
@Override
public void nodeChanged() throws Exception {
refreshConfiguration();
}
});
} catch (Exception e) {
client.close();
throw e;
}
} catch (Exception e) {
lifecycleState = LifecycleState.ERROR;
if (e instanceof RuntimeException) {
throw (RuntimeException) e;
} else {
throw new FlumeException(e);
}
}
lifecycleState = LifecycleState.START;
}
private void refreshConfiguration() throws IOException {
LOGGER.info("Refreshing configuration from ZooKeeper");
byte[] data = null;
ChildData childData = agentNodeCache.getCurrentData();
if (childData != null) {
data = childData.getData();
}
flumeConfiguration = configFromBytes(data);
eventBus.post(getConfiguration());
}
@Override
public void stop() {
LOGGER.debug("Stopping...");
if (agentNodeCache != null) {
try {
agentNodeCache.close();
} catch (IOException e) {
LOGGER.warn("Encountered exception while stopping", e);
lifecycleState = LifecycleState.ERROR;
}
}
try {
client.close();
} catch (Exception e) {
LOGGER.warn("Error stopping Curator client", e);
lifecycleState = LifecycleState.ERROR;
}
if (lifecycleState != LifecycleState.ERROR) {
lifecycleState = LifecycleState.STOP;
}
}
@Override
public LifecycleState getLifecycleState() {
return lifecycleState;
}
}