io.druid.indexing.overlord.TaskRunner Maven / Gradle / Ivy
/*
* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets 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 io.druid.indexing.overlord;
import com.google.common.base.Optional;
import com.google.common.util.concurrent.ListenableFuture;
import io.druid.indexing.common.TaskStatus;
import io.druid.indexing.common.task.Task;
import io.druid.indexing.overlord.autoscaling.ScalingStats;
import io.druid.java.util.common.Pair;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.Executor;
/**
* Interface for handing off tasks. Managed by a {@link io.druid.indexing.overlord.TaskQueue}.
* Holds state
*/
public interface TaskRunner
{
/**
* Some task runners can restart previously-running tasks after being bounced. This method does that, and returns
* the list of tasks (and status futures).
*/
List>> restore();
/**
* Register a listener with this task runner. On registration, the listener will get events corresponding to the
* current state of known tasks.
*
* Listener notifications are submitted to the executor in the order they occur, but it is up to the executor
* to decide when to actually run the notifications. If your listeners will not block, feel free to use a
* same-thread executor. Listeners that may block should use a separate executor, generally a single-threaded
* one with a fifo queue so the order of notifications is retained.
*
* @param listener the listener
* @param executor executor to run callbacks in
*/
void registerListener(TaskRunnerListener listener, Executor executor);
void unregisterListener(String listenerId);
/**
* Run a task. The returned status should be some kind of completed status.
*
* @param task task to run
*
* @return task status, eventually
*/
ListenableFuture run(Task task);
/**
* Inform the task runner it can clean up any resources associated with a task. This implies shutdown of any
* currently-running tasks.
*
* @param taskid task ID to clean up resources for
*/
void shutdown(String taskid);
/**
* Stop this task runner. This may block until currently-running tasks can be gracefully stopped. After calling
* stopping, "run" will not accept further tasks.
*/
void stop();
Collection getRunningTasks();
Collection getPendingTasks();
Collection getKnownTasks();
/**
* Some runners are able to scale up and down their capacity in a dynamic manner. This returns stats on those activities
*
* @return ScalingStats if the runner has an underlying resource which can scale, Optional.absent() otherwise
*/
Optional getScalingStats();
/**
* Start the state of the runner
*/
void start();
}