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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.master;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.message.ParameterizedMessage;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.action.ActionListenerResponseHandler;
import org.elasticsearch.action.ActionResponse;
import org.elasticsearch.action.ActionRunnable;
import org.elasticsearch.action.support.ActionFilters;
import org.elasticsearch.action.support.HandledTransportAction;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.ClusterStateObserver;
import org.elasticsearch.cluster.MasterNodeChangePredicate;
import org.elasticsearch.cluster.NotMasterException;
import org.elasticsearch.cluster.block.ClusterBlockException;
import org.elasticsearch.cluster.coordination.FailedToCommitClusterStateException;
import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.cluster.node.DiscoveryNodes;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.Writeable;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.discovery.MasterNotDiscoveredException;
import org.elasticsearch.node.NodeClosedException;
import org.elasticsearch.tasks.Task;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.ConnectTransportException;
import org.elasticsearch.transport.RemoteTransportException;
import org.elasticsearch.transport.TransportException;
import org.elasticsearch.transport.TransportService;
import java.io.IOException;
import java.util.function.Predicate;
/**
* A base class for operations that needs to be performed on the master node.
*/
public abstract class TransportMasterNodeAction, Response extends ActionResponse>
extends HandledTransportAction {
private static final Logger logger = LogManager.getLogger(TransportMasterNodeAction.class);
protected final ThreadPool threadPool;
protected final TransportService transportService;
protected final ClusterService clusterService;
protected final IndexNameExpressionResolver indexNameExpressionResolver;
private final String executor;
protected TransportMasterNodeAction(String actionName, TransportService transportService,
ClusterService clusterService, ThreadPool threadPool, ActionFilters actionFilters,
Writeable.Reader request, IndexNameExpressionResolver indexNameExpressionResolver) {
this(actionName, true, transportService, clusterService, threadPool, actionFilters, request, indexNameExpressionResolver);
}
protected TransportMasterNodeAction(String actionName, boolean canTripCircuitBreaker,
TransportService transportService, ClusterService clusterService, ThreadPool threadPool,
ActionFilters actionFilters, Writeable.Reader request,
IndexNameExpressionResolver indexNameExpressionResolver) {
super(actionName, canTripCircuitBreaker, transportService, actionFilters, request);
this.transportService = transportService;
this.clusterService = clusterService;
this.threadPool = threadPool;
this.indexNameExpressionResolver = indexNameExpressionResolver;
this.executor = executor();
}
protected abstract String executor();
protected abstract Response read(StreamInput in) throws IOException;
protected abstract void masterOperation(Request request, ClusterState state, ActionListener listener) throws Exception;
/**
* Override this operation if access to the task parameter is needed
*/
protected void masterOperation(Task task, Request request, ClusterState state, ActionListener listener) throws Exception {
masterOperation(request, state, listener);
}
protected boolean localExecute(Request request) {
return false;
}
protected abstract ClusterBlockException checkBlock(Request request, ClusterState state);
@Override
protected void doExecute(Task task, final Request request, ActionListener listener) {
new AsyncSingleAction(task, request, listener).start();
}
class AsyncSingleAction {
private final ActionListener listener;
private final Request request;
private volatile ClusterStateObserver observer;
private final Task task;
AsyncSingleAction(Task task, Request request, ActionListener listener) {
this.task = task;
this.request = request;
if (task != null) {
request.setParentTask(clusterService.localNode().getId(), task.getId());
}
this.listener = listener;
}
public void start() {
ClusterState state = clusterService.state();
this.observer
= new ClusterStateObserver(state, clusterService, request.masterNodeTimeout(), logger, threadPool.getThreadContext());
doStart(state);
}
protected void doStart(ClusterState clusterState) {
try {
final Predicate masterChangePredicate = MasterNodeChangePredicate.build(clusterState);
final DiscoveryNodes nodes = clusterState.nodes();
if (nodes.isLocalNodeElectedMaster() || localExecute(request)) {
// check for block, if blocked, retry, else, execute locally
final ClusterBlockException blockException = checkBlock(request, clusterState);
if (blockException != null) {
if (!blockException.retryable()) {
listener.onFailure(blockException);
} else {
logger.trace("can't execute due to a cluster block, retrying", blockException);
retry(blockException, newState -> {
try {
ClusterBlockException newException = checkBlock(request, newState);
return (newException == null || !newException.retryable());
} catch (Exception e) {
// accept state as block will be rechecked by doStart() and listener.onFailure() then called
logger.trace("exception occurred during cluster block checking, accepting state", e);
return true;
}
});
}
} else {
ActionListener delegate = ActionListener.delegateResponse(listener, (delegatedListener, t) -> {
if (t instanceof FailedToCommitClusterStateException || t instanceof NotMasterException) {
logger.debug(() -> new ParameterizedMessage("master could not publish cluster state or " +
"stepped down before publishing action [{}], scheduling a retry", actionName), t);
retry(t, masterChangePredicate);
} else {
delegatedListener.onFailure(t);
}
});
threadPool.executor(executor)
.execute(ActionRunnable.wrap(delegate, l -> masterOperation(task, request, clusterState, l)));
}
} else {
if (nodes.getMasterNode() == null) {
logger.debug("no known master node, scheduling a retry");
retry(null, masterChangePredicate);
} else {
DiscoveryNode masterNode = nodes.getMasterNode();
final String actionName = getMasterActionName(masterNode);
transportService.sendRequest(masterNode, actionName, request,
new ActionListenerResponseHandler(listener, TransportMasterNodeAction.this::read) {
@Override
public void handleException(final TransportException exp) {
Throwable cause = exp.unwrapCause();
if (cause instanceof ConnectTransportException ||
(exp instanceof RemoteTransportException && cause instanceof NodeClosedException)) {
// we want to retry here a bit to see if a new master is elected
logger.debug("connection exception while trying to forward request with action name [{}] to " +
"master node [{}], scheduling a retry. Error: [{}]",
actionName, nodes.getMasterNode(), exp.getDetailedMessage());
retry(cause, masterChangePredicate);
} else {
listener.onFailure(exp);
}
}
});
}
}
} catch (Exception e) {
listener.onFailure(e);
}
}
private void retry(final Throwable failure, final Predicate statePredicate) {
observer.waitForNextChange(
new ClusterStateObserver.Listener() {
@Override
public void onNewClusterState(ClusterState state) {
doStart(state);
}
@Override
public void onClusterServiceClose() {
listener.onFailure(new NodeClosedException(clusterService.localNode()));
}
@Override
public void onTimeout(TimeValue timeout) {
logger.debug(() -> new ParameterizedMessage("timed out while retrying [{}] after failure (timeout [{}])",
actionName, timeout), failure);
listener.onFailure(new MasterNotDiscoveredException(failure));
}
}, statePredicate
);
}
}
/**
* Allows to conditionally return a different master node action name in the case an action gets renamed.
* This mainly for backwards compatibility should be used rarely
*/
protected String getMasterActionName(DiscoveryNode node) {
return actionName;
}
}