gobblin.publisher.CommitSequencePublisher.java Source code

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Here is the source code for gobblin.publisher.CommitSequencePublisher.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 gobblin.publisher;

import java.io.IOException;
import java.util.Collection;

import org.apache.hadoop.fs.Path;

import com.google.common.base.Optional;
import com.google.common.collect.Iterables;

import gobblin.annotation.Alpha;
import gobblin.commit.CommitSequence;
import gobblin.commit.FsRenameCommitStep;
import gobblin.configuration.ConfigurationKeys;
import gobblin.configuration.State;
import gobblin.configuration.WorkUnitState;
import gobblin.util.ParallelRunner;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;

/**
 * An implementation of {@link DataPublisher} for exactly-once delivery.
 *
 * <p>
 *   This publisher does not actually publish data, instead it constructs a {@link CommitSequence.Builder}.
 *   The builder is used by Gobblin runtime to build a {@link CommitSequence}, which is then persisted
 *   and executed.
 * </p>
 *
 * @author Ziyang Liu
 */
@Alpha
@Slf4j
public class CommitSequencePublisher extends BaseDataPublisher {
    @Getter
    protected Optional<CommitSequence.Builder> commitSequenceBuilder = Optional.of(new CommitSequence.Builder());

    public CommitSequencePublisher(State state) throws IOException {
        super(state);
    }

    @Override
    public void publish(Collection<? extends WorkUnitState> states) throws IOException {
        super.publish(states);

        if (!states.isEmpty()) {

            String jobName = Iterables.get(states, 0).getProp(ConfigurationKeys.JOB_NAME_KEY);
            String datasetUrn = Iterables.get(states, 0).getProp(ConfigurationKeys.DATASET_URN_KEY,
                    ConfigurationKeys.DEFAULT_DATASET_URN);
            this.commitSequenceBuilder.get().withJobName(jobName).withDatasetUrn(datasetUrn);
        } else {
            log.warn("No workunitstate to publish");
            this.commitSequenceBuilder = Optional.<CommitSequence.Builder>absent();
        }
    }

    /**
     * This method does not actually move data, but it creates an {@link FsRenameCommitStep}.
     */
    @Override
    protected void movePath(ParallelRunner parallelRunner, State state, Path src, Path dst, int branchId)
            throws IOException {
        log.info(String.format("Creating CommitStep for moving %s to %s", src, dst));
        boolean overwrite = state.getPropAsBoolean(ConfigurationKeys.DATA_PUBLISHER_OVERWRITE_ENABLED, false);
        FsRenameCommitStep.Builder<?> builder = this.commitSequenceBuilder.get()
                .beginStep(FsRenameCommitStep.Builder.class).withProps(this.state).from(src)
                .withSrcFs(this.writerFileSystemByBranches.get(branchId)).to(dst)
                .withDstFs(this.publisherFileSystemByBranches.get(branchId));
        if (overwrite) {
            builder.overwrite();
        }

        builder.endStep();
    }

}