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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.persistent;
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.admin.cluster.node.tasks.cancel.CancelTasksResponse;
import org.elasticsearch.cluster.ClusterChangedEvent;
import org.elasticsearch.cluster.ClusterStateListener;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.gateway.GatewayService;
import org.elasticsearch.persistent.PersistentTasksCustomMetaData.PersistentTask;
import org.elasticsearch.tasks.Task;
import org.elasticsearch.tasks.TaskAwareRequest;
import org.elasticsearch.tasks.TaskId;
import org.elasticsearch.tasks.TaskManager;
import java.io.IOException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import static java.util.Objects.requireNonNull;
/**
* This component is responsible for coordination of execution of persistent tasks on individual nodes. It runs on all
* non-transport client nodes in the cluster and monitors cluster state changes to detect started commands.
*/
public class PersistentTasksNodeService implements ClusterStateListener {
private static final Logger logger = LogManager.getLogger(PersistentTasksNodeService.class);
private final Map runningTasks = new HashMap<>();
private final PersistentTasksService persistentTasksService;
private final PersistentTasksExecutorRegistry persistentTasksExecutorRegistry;
private final TaskManager taskManager;
private final NodePersistentTasksExecutor nodePersistentTasksExecutor;
public PersistentTasksNodeService(PersistentTasksService persistentTasksService,
PersistentTasksExecutorRegistry persistentTasksExecutorRegistry,
TaskManager taskManager, NodePersistentTasksExecutor nodePersistentTasksExecutor) {
this.persistentTasksService = persistentTasksService;
this.persistentTasksExecutorRegistry = persistentTasksExecutorRegistry;
this.taskManager = taskManager;
this.nodePersistentTasksExecutor = nodePersistentTasksExecutor;
}
@Override
public void clusterChanged(ClusterChangedEvent event) {
if (event.state().blocks().hasGlobalBlock(GatewayService.STATE_NOT_RECOVERED_BLOCK)) {
// wait until the gateway has recovered from disk, otherwise if the only master restarts
// we start cancelling all local tasks before cluster has a chance to recover.
return;
}
PersistentTasksCustomMetaData tasks = event.state().getMetaData().custom(PersistentTasksCustomMetaData.TYPE);
PersistentTasksCustomMetaData previousTasks = event.previousState().getMetaData().custom(PersistentTasksCustomMetaData.TYPE);
// Cluster State Local State Local Action
// STARTED NULL Create as STARTED, Start
// STARTED STARTED Noop - running
// STARTED COMPLETED Noop - waiting for notification ack
// NULL NULL Noop - nothing to do
// NULL STARTED Remove locally, Mark as PENDING_CANCEL, Cancel
// NULL COMPLETED Remove locally
// Master states:
// NULL - doesn't exist in the cluster state
// STARTED - exist in the cluster state
// Local state:
// NULL - we don't have task registered locally in runningTasks
// STARTED - registered in TaskManager, requires master notification when finishes
// PENDING_CANCEL - registered in TaskManager, doesn't require master notification when finishes
// COMPLETED - not registered in TaskManager, notified, waiting for master to remove it from CS so we can remove locally
// When task finishes if it is marked as STARTED or PENDING_CANCEL it is marked as COMPLETED and unregistered,
// If the task was STARTED, the master notification is also triggered (this is handled by unregisterTask() method, which is
// triggered by PersistentTaskListener
if (Objects.equals(tasks, previousTasks) == false || event.nodesChanged()) {
// We have some changes let's check if they are related to our node
String localNodeId = event.state().getNodes().getLocalNodeId();
Set notVisitedTasks = new HashSet<>(runningTasks.keySet());
if (tasks != null) {
for (PersistentTask taskInProgress : tasks.tasks()) {
if (localNodeId.equals(taskInProgress.getExecutorNode())) {
Long allocationId = taskInProgress.getAllocationId();
AllocatedPersistentTask persistentTask = runningTasks.get(allocationId);
if (persistentTask == null) {
// New task - let's start it
try {
startTask(taskInProgress);
} catch (Exception e) {
logger.error("Unable to start allocated task [" + taskInProgress.getTaskName()
+ "] with id [" + taskInProgress.getId()
+ "] and allocation id [" + taskInProgress.getAllocationId() + "]", e);
}
} else {
// The task is still running
notVisitedTasks.remove(allocationId);
}
}
}
}
for (Long id : notVisitedTasks) {
AllocatedPersistentTask task = runningTasks.get(id);
if (task.isCompleted()) {
// Result was sent to the caller and the caller acknowledged acceptance of the result
logger.trace("Found completed persistent task [{}] with id [{}] and allocation id [{}] - removing",
task.getAction(), task.getPersistentTaskId(), task.getAllocationId());
runningTasks.remove(id);
} else {
// task is running locally, but master doesn't know about it - that means that the persistent task was removed
// cancel the task without notifying master
logger.trace("Found unregistered persistent task [{}] with id [{}] and allocation id [{}] - cancelling",
task.getAction(), task.getPersistentTaskId(), task.getAllocationId());
cancelTask(id);
}
}
}
}
private void startTask(PersistentTask taskInProgress) {
PersistentTasksExecutor executor =
persistentTasksExecutorRegistry.getPersistentTaskExecutorSafe(taskInProgress.getTaskName());
TaskAwareRequest request = new TaskAwareRequest() {
TaskId parentTaskId = new TaskId("cluster", taskInProgress.getAllocationId());
@Override
public void setParentTask(TaskId taskId) {
throw new UnsupportedOperationException("parent task if for persistent tasks shouldn't change");
}
@Override
public TaskId getParentTask() {
return parentTaskId;
}
@Override
public Task createTask(long id, String type, String action, TaskId parentTaskId, Map headers) {
return executor.createTask(id, type, action, parentTaskId, taskInProgress, headers);
}
};
AllocatedPersistentTask task;
try {
task = (AllocatedPersistentTask) taskManager.register("persistent", taskInProgress.getTaskName() + "[c]", request);
} catch (Exception e) {
logger.error("Fatal error registering persistent task [" + taskInProgress.getTaskName()
+ "] with id [" + taskInProgress.getId() + "] and allocation id [" + taskInProgress.getAllocationId()
+ "], removing from persistent tasks", e);
notifyMasterOfFailedTask(taskInProgress, e);
return;
}
boolean processed = false;
try {
task.init(persistentTasksService, taskManager, taskInProgress.getId(), taskInProgress.getAllocationId());
logger.trace("Persistent task [{}] with id [{}] and allocation id [{}] was created", task.getAction(),
task.getPersistentTaskId(), task.getAllocationId());
try {
runningTasks.put(taskInProgress.getAllocationId(), task);
nodePersistentTasksExecutor.executeTask(taskInProgress.getParams(), taskInProgress.getState(), task, executor);
} catch (Exception e) {
// Submit task failure
task.markAsFailed(e);
}
processed = true;
} finally {
if (processed == false) {
// something went wrong - unregistering task
logger.warn("Persistent task [{}] with id [{}] and allocation id [{}] failed to create", task.getAction(),
task.getPersistentTaskId(), task.getAllocationId());
taskManager.unregister(task);
}
}
}
private void notifyMasterOfFailedTask(PersistentTask taskInProgress,
Exception originalException) {
persistentTasksService.sendCompletionRequest(taskInProgress.getId(), taskInProgress.getAllocationId(), originalException,
new ActionListener>() {
@Override
public void onResponse(PersistentTask persistentTask) {
logger.trace("completion notification for failed task [{}] with id [{}] was successful", taskInProgress.getTaskName(),
taskInProgress.getAllocationId());
}
@Override
public void onFailure(Exception notificationException) {
notificationException.addSuppressed(originalException);
logger.warn(new ParameterizedMessage("notification for task [{}] with id [{}] failed",
taskInProgress.getTaskName(), taskInProgress.getAllocationId()), notificationException);
}
});
}
/**
* Unregisters and then cancels the locally running task using the task manager. No notification to master will be send upon
* cancellation.
*/
private void cancelTask(Long allocationId) {
AllocatedPersistentTask task = runningTasks.remove(allocationId);
if (task.markAsCancelled()) {
// Cancel the local task using the task manager
String reason = "task has been removed, cancelling locally";
persistentTasksService.sendCancelRequest(task.getId(), reason, new ActionListener() {
@Override
public void onResponse(CancelTasksResponse cancelTasksResponse) {
logger.trace("Persistent task [{}] with id [{}] and allocation id [{}] was cancelled", task.getAction(),
task.getPersistentTaskId(), task.getAllocationId());
}
@Override
public void onFailure(Exception e) {
// There is really nothing we can do in case of failure here
logger.warn(() -> new ParameterizedMessage(
"failed to cancel task [{}] with id [{}] and allocation id [{}]",
task.getAction(), task.getPersistentTaskId(), task.getAllocationId()), e);
}
});
}
}
public static class Status implements Task.Status {
public static final String NAME = "persistent_executor";
private final AllocatedPersistentTask.State state;
public Status(AllocatedPersistentTask.State state) {
this.state = requireNonNull(state, "State cannot be null");
}
public Status(StreamInput in) throws IOException {
state = AllocatedPersistentTask.State.valueOf(in.readString());
}
@Override
public String getWriteableName() {
return NAME;
}
@Override
public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
builder.startObject();
builder.field("state", state.toString());
builder.endObject();
return builder;
}
@Override
public void writeTo(StreamOutput out) throws IOException {
out.writeString(state.toString());
}
@Override
public String toString() {
return Strings.toString(this);
}
@Override
public boolean isFragment() {
return false;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Status status = (Status) o;
return state == status.state;
}
@Override
public int hashCode() {
return Objects.hash(state);
}
}
}