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* 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.custom;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.Version;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.action.ActionResponse;
import org.elasticsearch.action.IndicesRequest;
import org.elasticsearch.action.NoShardAvailableActionException;
import org.elasticsearch.action.support.ActionFilters;
import org.elasticsearch.action.support.IndicesOptions;
import org.elasticsearch.action.support.TransportAction;
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.node.DiscoveryNode;
import org.elasticsearch.cluster.node.DiscoveryNodes;
import org.elasticsearch.cluster.routing.ShardRouting;
import org.elasticsearch.cluster.routing.ShardsIterator;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.index.shard.ShardId;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.*;
import java.io.IOException;
/**
* Transport action used to send a read request to one of the shards that belong to an index.
* Supports retrying another shard in case of failure.
*/
public abstract class TransportSingleCustomOperationAction<Request extends SingleCustomOperationRequest, Response extends ActionResponse> extends TransportAction<Request, Response> {
protected final ClusterService clusterService;
protected final TransportService transportService;
final String transportShardAction;
final String executor;
protected TransportSingleCustomOperationAction(Settings settings, String actionName, ThreadPool threadPool, ClusterService clusterService, TransportService transportService, ActionFilters actionFilters) {
super(settings, actionName, threadPool, actionFilters);
this.clusterService = clusterService;
this.transportService = transportService;
this.transportShardAction = actionName + "[s]";
this.executor = executor();
transportService.registerHandler(transportShardAction, new ShardTransportHandler());
}
@Override
protected void doExecute(Request request, ActionListener<Response> listener) {
new AsyncSingleAction(request, listener).start();
}
protected abstract String executor();
/**
* Can return null to execute on this local node.
*/
protected abstract ShardsIterator shards(ClusterState state, InternalRequest request);
/**
* Operation to be executed at the shard level. Can be called with shardId set to null, meaning that there is no
* shard involved and the operation just needs to be executed on the local node.
*/
protected abstract Response shardOperation(Request request, ShardId shardId) throws ElasticsearchException;
protected abstract Request newRequest();
protected abstract Response newResponse();
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 abstract boolean resolveIndex(Request request);
private class AsyncSingleAction {
private final ActionListener<Response> listener;
private final ShardsIterator shardsIt;
private final InternalRequest internalRequest;
private final DiscoveryNodes nodes;
private AsyncSingleAction(Request request, ActionListener<Response> listener) {
this.listener = listener;
ClusterState clusterState = clusterService.state();
nodes = clusterState.nodes();
ClusterBlockException blockException = checkGlobalBlock(clusterState);
if (blockException != null) {
throw blockException;
}
String concreteSingleIndex;
if (resolveIndex(request)) {
concreteSingleIndex = clusterState.metaData().concreteSingleIndex(request.index(), request.indicesOptions());
} else {
concreteSingleIndex = request.index();
}
this.internalRequest = new InternalRequest(request, concreteSingleIndex);
blockException = checkRequestBlock(clusterState, internalRequest);
if (blockException != null) {
throw blockException;
}
this.shardsIt = shards(clusterState, internalRequest);
}
public void start() {
performFirst();
}
private void onFailure(ShardRouting shardRouting, Throwable e) {
if (logger.isTraceEnabled() && e != null) {
logger.trace(shardRouting.shortSummary() + ": Failed to execute [" + internalRequest.request() + "]", e);
}
perform(e);
}
/**
* First get should try and use a shard that exists on a local node for better performance
*/
private void performFirst() {
if (shardsIt == null) {
// just execute it on the local node
if (internalRequest.request().operationThreaded()) {
internalRequest.request().beforeLocalFork();
threadPool.executor(executor()).execute(new Runnable() {
@Override
public void run() {
try {
Response response = shardOperation(internalRequest.request(), null);
listener.onResponse(response);
} catch (Throwable e) {
onFailure(null, e);
}
}
});
return;
} else {
try {
final Response response = shardOperation(internalRequest.request(), null);
listener.onResponse(response);
return;
} catch (Throwable e) {
onFailure(null, e);
}
}
return;
}
if (internalRequest.request().preferLocalShard()) {
boolean foundLocal = false;
ShardRouting shardX;
while ((shardX = shardsIt.nextOrNull()) != null) {
final ShardRouting shard = shardX;
if (shard.currentNodeId().equals(nodes.localNodeId())) {
foundLocal = true;
if (internalRequest.request().operationThreaded()) {
internalRequest.request().beforeLocalFork();
threadPool.executor(executor()).execute(new Runnable() {
@Override
public void run() {
try {
Response response = shardOperation(internalRequest.request(), shard.shardId());
listener.onResponse(response);
} catch (Throwable e) {
shardsIt.reset();
onFailure(shard, e);
}
}
});
return;
} else {
try {
final Response response = shardOperation(internalRequest.request(), shard.shardId());
listener.onResponse(response);
return;
} catch (Throwable e) {
shardsIt.reset();
onFailure(shard, e);
}
}
}
}
if (!foundLocal) {
// no local node get, go remote
shardsIt.reset();
perform(null);
}
} else {
perform(null);
}
}
private void perform(final Throwable lastException) {
final ShardRouting shard = shardsIt == null ? null : shardsIt.nextOrNull();
if (shard == null) {
Throwable failure = lastException;
if (failure == null) {
failure = new NoShardAvailableActionException(null, "No shard available for [" + internalRequest.request() + "]");
} else {
if (logger.isDebugEnabled()) {
logger.debug("failed to execute [" + internalRequest.request() + "]", failure);
}
}
listener.onFailure(failure);
} else {
if (shard.currentNodeId().equals(nodes.localNodeId())) {
// we don't prefer local shard, so try and do it here
if (!internalRequest.request().preferLocalShard()) {
try {
if (internalRequest.request().operationThreaded()) {
internalRequest.request().beforeLocalFork();
threadPool.executor(executor).execute(new Runnable() {
@Override
public void run() {
try {
Response response = shardOperation(internalRequest.request(), shard.shardId());
listener.onResponse(response);
} catch (Throwable e) {
onFailure(shard, e);
}
}
});
} else {
final Response response = shardOperation(internalRequest.request(), shard.shardId());
listener.onResponse(response);
}
} catch (Throwable e) {
onFailure(shard, e);
}
} else {
perform(lastException);
}
} else {
DiscoveryNode node = nodes.get(shard.currentNodeId());
transportService.sendRequest(node, transportShardAction, new ShardSingleOperationRequest(internalRequest.request(), shard.shardId()), new BaseTransportResponseHandler<Response>() {
@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(shard, exp);
}
});
}
}
}
}
private class ShardTransportHandler extends BaseTransportRequestHandler<ShardSingleOperationRequest> {
@Override
public ShardSingleOperationRequest newInstance() {
return new ShardSingleOperationRequest();
}
@Override
public String executor() {
return executor;
}
@Override
public void messageReceived(final ShardSingleOperationRequest request, final TransportChannel channel) throws Exception {
Response response = shardOperation(request.request(), request.shardId());
channel.sendResponse(response);
}
}
protected class ShardSingleOperationRequest extends TransportRequest implements IndicesRequest {
private Request request;
private ShardId shardId;
ShardSingleOperationRequest() {
}
public ShardSingleOperationRequest(Request request, ShardId shardId) {
super(request);
this.request = request;
this.shardId = shardId;
}
public Request request() {
return request;
}
@Override
public String[] indices() {
return request.indices();
}
@Override
public IndicesOptions indicesOptions() {
return request.indicesOptions();
}
public ShardId shardId() {
return shardId;
}
@Override
public void readFrom(StreamInput in) throws IOException {
super.readFrom(in);
request = newRequest();
request.readFrom(in);
if (in.getVersion().onOrAfter(Version.V_1_4_0_Beta1)) {
shardId = ShardId.readShardId(in);
} else {
//older nodes will send the concrete index as part of the request
shardId = new ShardId(request.index(), in.readVInt());
}
}
@Override
public void writeTo(StreamOutput out) throws IOException {
super.writeTo(out);
if (out.getVersion().before(Version.V_1_4_0_Beta1)) {
//older nodes expect the concrete index as part of the request
request.index(shardId.getIndex());
}
request.writeTo(out);
if (out.getVersion().onOrAfter(Version.V_1_4_0_Beta1)) {
shardId.writeTo(out);
} else {
out.writeVInt(shardId.id());
}
}
}
/**
* 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;
}
}
}