org.apache.gobblin.service.modules.spec.JobExecutionPlanDagFactory.java Source code

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Here is the source code for org.apache.gobblin.service.modules.spec.JobExecutionPlanDagFactory.java

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/*
 * 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.gobblin.service.modules.spec;

import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.hadoop.fs.Path;

import com.google.common.base.Optional;
import com.google.common.io.Files;
import com.typesafe.config.Config;

import lombok.extern.slf4j.Slf4j;

import org.apache.gobblin.annotation.Alpha;
import org.apache.gobblin.configuration.ConfigurationKeys;
import org.apache.gobblin.runtime.api.JobSpec;
import org.apache.gobblin.service.modules.flowgraph.Dag;

/**
 * A Factory class used for constructing a {@link Dag} of {@link JobExecutionPlan}s from
 * a {@link List} of {@link JobExecutionPlan}s.
 */
@Alpha
@Slf4j
public class JobExecutionPlanDagFactory {

    public Dag<JobExecutionPlan> createDag(List<JobExecutionPlan> jobExecutionPlans) {
        //Maintain a mapping between job name and the corresponding JobExecutionPlan.
        Map<String, Dag.DagNode<JobExecutionPlan>> JobExecutionPlanMap = new HashMap<>();
        List<Dag.DagNode<JobExecutionPlan>> dagNodeList = new ArrayList<>();
        /**
         * Create a {@link Dag.DagNode<JobExecutionPlan>} for every {@link JobSpec} in the flow. Add this node
         * to a HashMap.
         */
        for (JobExecutionPlan jobExecutionPlan : jobExecutionPlans) {
            Dag.DagNode<JobExecutionPlan> dagNode = new Dag.DagNode<>(jobExecutionPlan);
            dagNodeList.add(dagNode);
            String jobName = getJobName(jobExecutionPlan);
            if (jobName != null) {
                JobExecutionPlanMap.put(jobName, dagNode);
            }
        }

        /**
         * Iterate over each {@link JobSpec} to get the dependencies of each {@link JobSpec}.
         * For each {@link JobSpec}, get the corresponding {@link Dag.DagNode} and
         * set the {@link Dag.DagNode}s corresponding to its dependencies as its parent nodes.
         *
         * TODO: we likely do not need 2 for loops and we can do this in 1 pass.
         */
        for (JobExecutionPlan jobExecutionPlan : jobExecutionPlans) {
            String jobName = getJobName(jobExecutionPlan);
            if (jobName == null) {
                continue;
            }
            Dag.DagNode<JobExecutionPlan> node = JobExecutionPlanMap.get(jobName);
            Collection<String> dependencies = getDependencies(jobExecutionPlan.getJobSpec().getConfig());
            for (String dependency : dependencies) {
                Dag.DagNode<JobExecutionPlan> parentNode = JobExecutionPlanMap.get(dependency);
                node.addParentNode(parentNode);
            }
        }
        Dag<JobExecutionPlan> dag = new Dag<>(dagNodeList);
        return dag;
    }

    /**
     * Get job dependencies of a given job from its config.
     * @param config of a job.
     * @return a list of dependencies of the job.
     */
    private static List<String> getDependencies(Config config) {
        return config.hasPath(ConfigurationKeys.JOB_DEPENDENCIES)
                ? Arrays.asList(config.getString(ConfigurationKeys.JOB_DEPENDENCIES).split(","))
                : new ArrayList<>();
    }

    /**
     * The job name is derived from the {@link org.apache.gobblin.runtime.api.JobTemplate} URI. It is the
     * simple name of the path component of the URI.
     * @param jobExecutionPlan
     * @return the simple name from the URI path.
     */
    private static String getJobName(JobExecutionPlan jobExecutionPlan) {
        Optional<URI> jobTemplateUri = jobExecutionPlan.getJobSpec().getTemplateURI();
        if (jobTemplateUri.isPresent()) {
            return Files.getNameWithoutExtension(new Path(jobTemplateUri.get()).getName());
        } else {
            return null;
        }
    }
}