himanshug commented on a change in pull request #8107: Add CliIndexer process type and initial task runner implementation URL: https://github.com/apache/incubator-druid/pull/8107#discussion_r307848163
########## File path: indexing-service/src/main/java/org/apache/druid/indexing/overlord/BaseRestorableTaskRunner.java ########## @@ -0,0 +1,222 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF 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.apache.druid.indexing.overlord; + +import com.fasterxml.jackson.annotation.JsonCreator; +import com.fasterxml.jackson.annotation.JsonProperty; +import com.fasterxml.jackson.databind.ObjectMapper; +import com.google.common.collect.ImmutableList; +import com.google.common.collect.Lists; +import com.google.common.io.Files; +import com.google.common.util.concurrent.ListenableFuture; +import com.google.errorprone.annotations.concurrent.GuardedBy; +import org.apache.druid.indexer.RunnerTaskState; +import org.apache.druid.indexer.TaskStatus; +import org.apache.druid.indexing.common.config.TaskConfig; +import org.apache.druid.indexing.common.task.Task; +import org.apache.druid.java.util.common.ISE; +import org.apache.druid.java.util.common.Pair; +import org.apache.druid.java.util.emitter.EmittingLogger; + +import javax.annotation.Nullable; +import java.io.File; +import java.util.ArrayList; +import java.util.Collection; +import java.util.List; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.CopyOnWriteArrayList; +import java.util.concurrent.Executor; + +/** + * Base class for {@link ForkingTaskRunner} and {@link ThreadingTaskRunner} which support task rest + * oration. + */ +public abstract class BaseRestorableTaskRunner<WorkItemType extends TaskRunnerWorkItem> implements TaskRunner +{ + protected static final EmittingLogger LOG = new EmittingLogger(BaseRestorableTaskRunner.class); + protected static final String TASK_RESTORE_FILENAME = "restore.json"; + + protected final CopyOnWriteArrayList<Pair<TaskRunnerListener, Executor>> listeners = new CopyOnWriteArrayList<>(); + + /** Writes must be synchronized. This is only a ConcurrentMap so "informational" reads can occur without waiting. */ + protected final ConcurrentHashMap<String, WorkItemType> tasks = new ConcurrentHashMap<>(); + protected final ObjectMapper jsonMapper; + protected final TaskConfig taskConfig; + + public BaseRestorableTaskRunner( + ObjectMapper jsonMapper, + TaskConfig taskConfig + ) + { + this.jsonMapper = jsonMapper; + this.taskConfig = taskConfig; + } + + @Override + public List<Pair<Task, ListenableFuture<TaskStatus>>> restore() + { + final File restoreFile = getRestoreFile(); + final TaskRestoreInfo taskRestoreInfo; + if (restoreFile.exists()) { + try { + taskRestoreInfo = jsonMapper.readValue(restoreFile, TaskRestoreInfo.class); + } + catch (Exception e) { + LOG.error(e, "Failed to read restorable tasks from file[%s]. Skipping restore.", restoreFile); + return ImmutableList.of(); + } + } else { + return ImmutableList.of(); + } + + final List<Pair<Task, ListenableFuture<TaskStatus>>> retVal = new ArrayList<>(); + for (final String taskId : taskRestoreInfo.getRunningTasks()) { + try { + final File taskFile = new File(taskConfig.getTaskDir(taskId), "task.json"); + final Task task = jsonMapper.readValue(taskFile, Task.class); + + if (!task.getId().equals(taskId)) { + throw new ISE("WTF?! Task[%s] restore file had wrong id[%s].", taskId, task.getId()); + } + + if (taskConfig.isRestoreTasksOnRestart() && task.canRestore()) { + LOG.info("Restoring task[%s].", task.getId()); + retVal.add(Pair.of(task, run(task))); + } + } + catch (Exception e) { + LOG.warn(e, "Failed to restore task[%s]. Trying to restore other tasks.", taskId); + } + } + + LOG.info("Restored %,d tasks.", retVal.size()); + + return retVal; + } + + @Override + public void registerListener(TaskRunnerListener listener, Executor executor) + { + for (Pair<TaskRunnerListener, Executor> pair : listeners) { + if (pair.lhs.getListenerId().equals(listener.getListenerId())) { + throw new ISE("Listener [%s] already registered", listener.getListenerId()); + } + } + + final Pair<TaskRunnerListener, Executor> listenerPair = Pair.of(listener, executor); + + synchronized (tasks) { + for (TaskRunnerWorkItem item : tasks.values()) { + TaskRunnerUtils.notifyLocationChanged(ImmutableList.of(listenerPair), item.getTaskId(), item.getLocation()); + } + + listeners.add(listenerPair); + LOG.info("Registered listener [%s]", listener.getListenerId()); + } + } + + @Override + public void unregisterListener(String listenerId) + { + for (Pair<TaskRunnerListener, Executor> pair : listeners) { + if (pair.lhs.getListenerId().equals(listenerId)) { + listeners.remove(pair); + LOG.info("Unregistered listener [%s]", listenerId); + return; + } + } + } + + /** + * The concrete implementation should override this, as the implemention depends on the specifics of the + * work item implementation. + */ + @Override + public abstract Collection<TaskRunnerWorkItem> getRunningTasks(); + + /** + * The concrete implementation should override this, as the implemention depends on the specifics of the + * work item implementation. + */ + @Override + public abstract Collection<TaskRunnerWorkItem> getPendingTasks(); + + /** + * The concrete implementation should override this, as the implemention depends on the specifics of the Review comment: nit: comments on these 3 methods have no value as those methods are already declared abstract. if we do, the comment should be about what is expected from implementors or no comment. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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