/**
* 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.availability;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.cloudera.flume.conf.Context;
import com.cloudera.flume.conf.FlumeConfiguration;
import com.cloudera.flume.conf.FlumeSpecException;
import com.cloudera.flume.conf.SinkFactory.SinkBuilder;
import com.cloudera.flume.core.BackOffFailOverSink;
import com.cloudera.flume.core.CompositeSink;
import com.cloudera.flume.core.Event;
import com.cloudera.flume.core.EventSink;
import com.cloudera.flume.reporter.ReportEvent;
import com.cloudera.flume.reporter.Reportable;
import com.cloudera.util.BackoffPolicy;
import com.cloudera.util.CappedExponentialBackoff;
import com.google.common.base.Preconditions;
/**
* This sink takes a list of hosts/ips to fall back onto. It generates a chain
* of lazyopening failover nodes
*/
public class FailoverChainSink extends EventSink.Base {
static final Logger LOG = LoggerFactory.getLogger(FailoverChainSink.class);
final EventSink snk;
public FailoverChainSink(Context context, String specFormat,
List<String> list, BackoffPolicy backoff) throws FlumeSpecException {
snk = buildSpec(context, specFormat, list, backoff);
}
public FailoverChainSink(Context context, String specFormat,
List<String> list, long initialBackoff, long maxBackoff)
throws FlumeSpecException {
snk = buildSpec(context, specFormat, list, new CappedExponentialBackoff(
initialBackoff, maxBackoff));
}
/**
* This current version requires a "%s" that gets replaced with the value from
* the list.
*
* Warning! this is a potential security problem.
*/
static EventSink buildSpec(Context context, String spec, List<String> list,
BackoffPolicy policy) throws FlumeSpecException {
// iterate through the list backwards
EventSink cur = null;
for (int i = list.size() - 1; i >= 0; i--) {
String s = list.get(i);
// this should be a composite sink.
String failoverSpec = String.format(spec, s);
LOG.debug("failover spec is : " + failoverSpec);
EventSink tsnk = new CompositeSink(context, failoverSpec);
if (cur == null) {
cur = tsnk;
continue;
}
cur = new BackOffFailOverSink(tsnk, cur, policy);
}
return cur;
}
@Override
public void append(Event e) throws IOException, InterruptedException {
snk.append(e);
super.append(e);
}
@Override
public void close() throws IOException, InterruptedException {
snk.close();
}
@Override
public void open() throws IOException, InterruptedException {
snk.open();
}
@Override
public ReportEvent getMetrics() {
return snk.getMetrics();
}
@Override
public Map<String, Reportable> getSubMetrics() {
return snk.getSubMetrics();
}
@Deprecated
@Override
public void getReports(String namePrefix, Map<String, ReportEvent> reports) {
super.getReports(namePrefix, reports);
snk.getReports(namePrefix + getName() + ".", reports);
}
public static SinkBuilder builder() {
return new SinkBuilder() {
@Override
public EventSink build(Context context, String... argv) {
Preconditions.checkArgument(argv.length >= 2);
String format = argv[0];
FlumeConfiguration conf = FlumeConfiguration.get();
List<String> list = Arrays.asList(argv);
list = list.subList(1, list.size());
try {
return new FailoverChainSink(context, format, list, conf
.getFailoverInitialBackoff(), conf.getFailoverMaxSingleBackoff());
} catch (FlumeSpecException e) {
LOG.error("Bad spec or format", e);
throw new IllegalArgumentException(e);
}
}
};
}
}