/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.cluster.routing;
import org.apache.logging.log4j.message.ParameterizedMessage;
import org.apache.logging.log4j.util.Supplier;
import org.elasticsearch.cluster.ClusterChangedEvent;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.ClusterStateUpdateTask;
import org.elasticsearch.cluster.routing.allocation.AllocationService;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.Priority;
import org.elasticsearch.common.component.AbstractLifecycleComponent;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.settings.Settings;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* A {@link RoutingService} listens to clusters state. When this service
* receives a {@link ClusterChangedEvent} the cluster state will be verified and
* the routing tables might be updated.
* <p>
* Note: The {@link RoutingService} is responsible for cluster wide operations
* that include modifications to the cluster state. Such an operation can only
* be performed on the clusters master node. Unless the local node this service
* is running on is the clusters master node this service will not perform any
* actions.
* </p>
*/
public class RoutingService extends AbstractLifecycleComponent {
private static final String CLUSTER_UPDATE_TASK_SOURCE = "cluster_reroute";
private final ClusterService clusterService;
private final AllocationService allocationService;
private AtomicBoolean rerouting = new AtomicBoolean();
@Inject
public RoutingService(Settings settings, ClusterService clusterService, AllocationService allocationService) {
super(settings);
this.clusterService = clusterService;
this.allocationService = allocationService;
}
@Override
protected void doStart() {
}
@Override
protected void doStop() {
}
@Override
protected void doClose() {
}
/**
* Initiates a reroute.
*/
public final void reroute(String reason) {
performReroute(reason);
}
// visible for testing
protected void performReroute(String reason) {
try {
if (lifecycle.stopped()) {
return;
}
if (rerouting.compareAndSet(false, true) == false) {
logger.trace("already has pending reroute, ignoring {}", reason);
return;
}
logger.trace("rerouting {}", reason);
clusterService.submitStateUpdateTask(CLUSTER_UPDATE_TASK_SOURCE + "(" + reason + ")", new ClusterStateUpdateTask(Priority.HIGH) {
@Override
public ClusterState execute(ClusterState currentState) {
rerouting.set(false);
return allocationService.reroute(currentState, reason);
}
@Override
public void onNoLongerMaster(String source) {
rerouting.set(false);
// no biggie
}
@Override
public void onFailure(String source, Exception e) {
rerouting.set(false);
ClusterState state = clusterService.state();
if (logger.isTraceEnabled()) {
logger.error((Supplier<?>) () -> new ParameterizedMessage("unexpected failure during [{}], current state:\n{}", source, state), e);
} else {
logger.error((Supplier<?>) () -> new ParameterizedMessage("unexpected failure during [{}], current state version [{}]", source, state.version()), e);
}
}
});
} catch (Exception e) {
rerouting.set(false);
ClusterState state = clusterService.state();
logger.warn((Supplier<?>) () -> new ParameterizedMessage("failed to reroute routing table, current state:\n{}", state), e);
}
}
}