/*
* Licensed to Elastic Search and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Elastic Search 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.elasticsearch.gateway.shared;
import org.elasticsearch.ElasticSearchException;
import org.elasticsearch.cluster.ClusterChangedEvent;
import org.elasticsearch.cluster.ClusterService;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.ClusterStateListener;
import org.elasticsearch.cluster.metadata.MetaData;
import org.elasticsearch.common.StopWatch;
import org.elasticsearch.common.component.AbstractLifecycleComponent;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.gateway.Gateway;
import org.elasticsearch.gateway.GatewayException;
import org.elasticsearch.threadpool.ThreadPool;
/**
* @author kimchy (shay.banon)
*/
public abstract class SharedStorageGateway extends AbstractLifecycleComponent<Gateway> implements Gateway, ClusterStateListener {
private final ClusterService clusterService;
private final ThreadPool threadPool;
public SharedStorageGateway(Settings settings, ThreadPool threadPool, ClusterService clusterService) {
super(settings);
this.threadPool = threadPool;
this.clusterService = clusterService;
}
@Override protected void doStart() throws ElasticSearchException {
clusterService.add(this);
}
@Override protected void doStop() throws ElasticSearchException {
clusterService.remove(this);
}
@Override protected void doClose() throws ElasticSearchException {
}
@Override public void performStateRecovery(final GatewayStateRecoveredListener listener) throws GatewayException {
threadPool.cached().execute(new Runnable() {
@Override public void run() {
logger.debug("reading state from gateway {} ...", this);
StopWatch stopWatch = new StopWatch().start();
MetaData metaData;
try {
metaData = read();
logger.debug("read state from gateway {}, took {}", this, stopWatch.stop().totalTime());
if (metaData == null) {
logger.debug("no state read from gateway");
listener.onSuccess(ClusterState.builder().build());
} else {
listener.onSuccess(ClusterState.builder().metaData(metaData).build());
}
} catch (Exception e) {
logger.error("failed to read from gateway", e);
listener.onFailure(e);
}
}
});
}
@Override public void clusterChanged(final ClusterChangedEvent event) {
if (!lifecycle.started()) {
return;
}
// nothing to do until we actually recover from the gateway or any other block indicates we need to disable persistency
if (event.state().blocks().disableStatePersistence()) {
return;
}
if (event.localNodeMaster()) {
if (!event.metaDataChanged()) {
return;
}
threadPool.cached().execute(new Runnable() {
@Override public void run() {
logger.debug("writing to gateway {} ...", this);
StopWatch stopWatch = new StopWatch().start();
try {
write(event.state().metaData());
logger.debug("wrote to gateway {}, took {}", this, stopWatch.stop().totalTime());
// TODO, we need to remember that we failed, maybe add a retry scheduler?
} catch (Exception e) {
logger.error("failed to write to gateway", e);
}
}
});
}
}
protected abstract MetaData read() throws ElasticSearchException;
protected abstract void write(MetaData metaData) throws ElasticSearchException;
}