org.elasticsearch.action.support.single.shard.TransportSingleShardAction Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
/*
* 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.action.support.single.shard;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.action.ActionResponse;
import org.elasticsearch.action.NoShardAvailableActionException;
import org.elasticsearch.action.support.ActionFilters;
import org.elasticsearch.action.support.TransportAction;
import org.elasticsearch.action.support.TransportActions;
import org.elasticsearch.cluster.ClusterService;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.block.ClusterBlockException;
import org.elasticsearch.cluster.block.ClusterBlockLevel;
import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.cluster.node.DiscoveryNodes;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.ShardsIterator;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.logging.support.LoggerMessageFormat;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.index.shard.ShardId;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.*;
import static org.elasticsearch.action.support.TransportActions.isShardNotAvailableException;
/**
* A base class for operations that need to perform a read operation on a single shard copy. If the operation fails,
* the read operation can be performed on other shard copies. Concrete implementations can provide their own list
* of candidate shards to try the read operation on.
*/
public abstract class TransportSingleShardAction extends TransportAction {
protected final ClusterService clusterService;
protected final TransportService transportService;
final String transportShardAction;
final String executor;
protected TransportSingleShardAction(Settings settings, String actionName, ThreadPool threadPool, ClusterService clusterService,
TransportService transportService, ActionFilters actionFilters, IndexNameExpressionResolver indexNameExpressionResolver,
Class request, String executor) {
super(settings, actionName, threadPool, actionFilters, indexNameExpressionResolver, transportService.getTaskManager());
this.clusterService = clusterService;
this.transportService = transportService;
this.transportShardAction = actionName + "[s]";
this.executor = executor;
if (!isSubAction()) {
transportService.registerRequestHandler(actionName, request, ThreadPool.Names.SAME, new TransportHandler());
}
transportService.registerRequestHandler(transportShardAction, request, executor, new ShardTransportHandler());
}
/**
* Tells whether the action is a main one or a subaction. Used to decide whether we need to register
* the main transport handler. In fact if the action is a subaction, its execute method
* will be called locally to its parent action.
*/
protected boolean isSubAction() {
return false;
}
@Override
protected void doExecute(Request request, ActionListener listener) {
new AsyncSingleAction(request, listener).start();
}
protected abstract Response shardOperation(Request request, ShardId shardId);
protected abstract Response newResponse();
protected abstract boolean resolveIndex(Request request);
protected ClusterBlockException checkGlobalBlock(ClusterState state) {
return state.blocks().globalBlockedException(ClusterBlockLevel.READ);
}
protected ClusterBlockException checkRequestBlock(ClusterState state, InternalRequest request) {
return state.blocks().indexBlockedException(ClusterBlockLevel.READ, request.concreteIndex());
}
protected void resolveRequest(ClusterState state, InternalRequest request) {
}
/**
* Returns the candidate shards to execute the operation on or null
the execute
* the operation locally (the node that received the request)
*/
@Nullable
protected abstract ShardsIterator shards(ClusterState state, InternalRequest request);
class AsyncSingleAction {
private final ActionListener listener;
private final ShardsIterator shardIt;
private final InternalRequest internalRequest;
private final DiscoveryNodes nodes;
private volatile Throwable lastFailure;
private AsyncSingleAction(Request request, ActionListener listener) {
this.listener = listener;
ClusterState clusterState = clusterService.state();
if (logger.isTraceEnabled()) {
logger.trace("executing [{}] based on cluster state version [{}]", request, clusterState.version());
}
nodes = clusterState.nodes();
ClusterBlockException blockException = checkGlobalBlock(clusterState);
if (blockException != null) {
throw blockException;
}
String concreteSingleIndex;
if (resolveIndex(request)) {
concreteSingleIndex = indexNameExpressionResolver.concreteSingleIndex(clusterState, request);
} else {
concreteSingleIndex = request.index();
}
this.internalRequest = new InternalRequest(request, concreteSingleIndex);
resolveRequest(clusterState, internalRequest);
blockException = checkRequestBlock(clusterState, internalRequest);
if (blockException != null) {
throw blockException;
}
this.shardIt = shards(clusterState, internalRequest);
}
public void start() {
if (shardIt == null) {
// just execute it on the local node
transportService.sendRequest(clusterService.localNode(), transportShardAction, internalRequest.request(), new BaseTransportResponseHandler() {
@Override
public Response newInstance() {
return newResponse();
}
@Override
public String executor() {
return ThreadPool.Names.SAME;
}
@Override
public void handleResponse(final Response response) {
listener.onResponse(response);
}
@Override
public void handleException(TransportException exp) {
listener.onFailure(exp);
}
});
} else {
perform(null);
}
}
private void onFailure(ShardRouting shardRouting, Throwable e) {
if (logger.isTraceEnabled() && e != null) {
logger.trace("{}: failed to execute [{}]", e, shardRouting, internalRequest.request());
}
perform(e);
}
private void perform(@Nullable final Throwable currentFailure) {
Throwable lastFailure = this.lastFailure;
if (lastFailure == null || TransportActions.isReadOverrideException(currentFailure)) {
lastFailure = currentFailure;
this.lastFailure = currentFailure;
}
final ShardRouting shardRouting = shardIt.nextOrNull();
if (shardRouting == null) {
Throwable failure = lastFailure;
if (failure == null || isShardNotAvailableException(failure)) {
failure = new NoShardAvailableActionException(null, LoggerMessageFormat.format("No shard available for [{}]", internalRequest.request()), failure);
} else {
if (logger.isDebugEnabled()) {
logger.debug("{}: failed to execute [{}]", failure, null, internalRequest.request());
}
}
listener.onFailure(failure);
return;
}
DiscoveryNode node = nodes.get(shardRouting.currentNodeId());
if (node == null) {
onFailure(shardRouting, new NoShardAvailableActionException(shardRouting.shardId()));
} else {
internalRequest.request().internalShardId = shardRouting.shardId();
if (logger.isTraceEnabled()) {
logger.trace(
"sending request [{}] to shard [{}] on node [{}]",
internalRequest.request(),
internalRequest.request().internalShardId,
node
);
}
transportService.sendRequest(node, transportShardAction, internalRequest.request(), new BaseTransportResponseHandler() {
@Override
public Response newInstance() {
return newResponse();
}
@Override
public String executor() {
return ThreadPool.Names.SAME;
}
@Override
public void handleResponse(final Response response) {
listener.onResponse(response);
}
@Override
public void handleException(TransportException exp) {
onFailure(shardRouting, exp);
}
});
}
}
}
private class TransportHandler extends TransportRequestHandler {
@Override
public void messageReceived(Request request, final TransportChannel channel) throws Exception {
// if we have a local operation, execute it on a thread since we don't spawn
request.operationThreaded(true);
execute(request, new ActionListener() {
@Override
public void onResponse(Response result) {
try {
channel.sendResponse(result);
} catch (Throwable e) {
onFailure(e);
}
}
@Override
public void onFailure(Throwable e) {
try {
channel.sendResponse(e);
} catch (Exception e1) {
logger.warn("failed to send response for get", e1);
}
}
});
}
}
private class ShardTransportHandler extends TransportRequestHandler {
@Override
public void messageReceived(final Request request, final TransportChannel channel) throws Exception {
if (logger.isTraceEnabled()) {
logger.trace("executing [{}] on shard [{}]", request, request.internalShardId);
}
Response response = shardOperation(request, request.internalShardId);
channel.sendResponse(response);
}
}
/**
* Internal request class that gets built on each node. Holds the original request plus additional info.
*/
protected class InternalRequest {
final Request request;
final String concreteIndex;
InternalRequest(Request request, String concreteIndex) {
this.request = request;
this.concreteIndex = concreteIndex;
}
public Request request() {
return request;
}
public String concreteIndex() {
return concreteIndex;
}
}
}