ml.shifu.guagua.master.MasterComputable Maven / Gradle / Ivy
/*
* Copyright [2013-2014] eBay Software Foundation
*
* Licensed 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 ml.shifu.guagua.master;
import ml.shifu.guagua.io.Bytable;
/**
* {@link MasterComputable} defines master computation for any guagua application. All guagua application should define
* its own master logic and to configure it by using guagua client configuration.
*
*
* Any context parameters like current iteration, worker results can be got from {@link MasterContext}.
*
*
* To get global properties like Hadoop and YARN configuration properties, {@link MasterContext#getProps()} is a wrapper
* for Hadoop Configuration. Anything configured by using '-D' in command line can be got from these properties.
*
*
* {@link MasterContext#getWorkerResults()} is the worker results from all the workers in current iteration. It can be
* used for master computation logic.
*
*
* Iteration starts from 1, ends with {@link MasterContext#getTotalIteration()}. Total iteration number can be set in
* command line through '-c' parameter.
*
*
* {@link MasterContext#getAppId()} denotes the job ID for a map-reduce job in Hadoop, or YARN application ID for a YARN
* application. {@link MasterContext#getContainerId()} denotes current master container. It is task partition index in
* Hadoop map-reduce job or split index in YARN guagua application. Container ID is unique for each master task, if
* current master task is restarted after failure, it should use the same container id to make sure guagua know who it
* is.
*
* @param
* master result for computation in each iteration.
* @param
* worker result for computation in each iteration.
*/
public interface MasterComputable {
/**
* Master computation for each iteration.
*
* @param context
* the master context instance which includes worker results and other useful parameters.
* @return
* the master result of each iteration.
*/
MASTER_RESULT compute(MasterContext context);
}