/*
* 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.flink.runtime.highavailability;
import org.apache.flink.api.common.JobID;
import java.io.IOException;
/**
* A simple registry that tracks if a certain job is pending execution, running, or completed.
*
* <p>This registry is used in highly-available setups with multiple master nodes,
* to determine whether a new leader should attempt to recover a certain job (because the
* job is still running), or whether the job has already finished successfully (in case of a
* finite job) and the leader has only been granted leadership because the previous leader
* quit cleanly after the job was finished.
*
* <p>In addition, the registry can help to determine whether a newly assigned leader JobManager
* should attempt reconciliation with running TaskManagers, or immediately schedule the job from
* the latest checkpoint/savepoint.
*/
public interface RunningJobsRegistry {
/**
* The scheduling status of a job, as maintained by the {@code RunningJobsRegistry}.
*/
enum JobSchedulingStatus {
/** Job has not been scheduled, yet */
PENDING,
/** Job has been scheduled and is not yet finished */
RUNNING,
/** Job has been finished, successfully or unsuccessfully */
DONE;
}
// ------------------------------------------------------------------------
/**
* Marks a job as running. Requesting the job's status via the {@link #getJobSchedulingStatus(JobID)}
* method will return {@link JobSchedulingStatus#RUNNING}.
*
* @param jobID The id of the job.
*
* @throws IOException Thrown when the communication with the highly-available storage or registry
* failed and could not be retried.
*/
void setJobRunning(JobID jobID) throws IOException;
/**
* Marks a job as completed. Requesting the job's status via the {@link #getJobSchedulingStatus(JobID)}
* method will return {@link JobSchedulingStatus#DONE}.
*
* @param jobID The id of the job.
*
* @throws IOException Thrown when the communication with the highly-available storage or registry
* failed and could not be retried.
*/
void setJobFinished(JobID jobID) throws IOException;
/**
* Gets the scheduling status of a job.
*
* @param jobID The id of the job to check.
* @return The job scheduling status.
*
* @throws IOException Thrown when the communication with the highly-available storage or registry
* failed and could not be retried.
*/
JobSchedulingStatus getJobSchedulingStatus(JobID jobID) throws IOException;
/**
* Clear job state form the registry, usually called after job finish
*
* @param jobID The id of the job to check.
*
* @throws IOException Thrown when the communication with the highly-available storage or registry
* failed and could not be retried.
*/
void clearJob(JobID jobID) throws IOException;
}