gobblin.util.commit.DeleteFileCommitStep.java Source code

Introduction

Here is the source code for gobblin.util.commit.DeleteFileCommitStep.java

Source

/*
 * 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.util.commit;

import java.io.IOException;
import java.net.URI;
import java.util.Collection;
import java.util.List;
import java.util.Properties;
import java.util.Set;

import javax.annotation.Nullable;
import lombok.Getter;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

import com.google.common.base.Function;
import com.google.common.base.Optional;
import com.google.common.collect.Lists;
import com.google.common.collect.Iterables;
import com.google.common.collect.Sets;

import gobblin.commit.CommitStep;
import gobblin.data.management.trash.Trash;
import gobblin.data.management.trash.TrashFactory;
import gobblin.util.PathUtils;

/**
 * {@link CommitStep} to delete a set of paths in a {@link FileSystem}.
 * If {@link #parentDeletionLimit} is present, will also delete newly empty parent directories up to but not including
 * that limit.
 */
@Getter
public class DeleteFileCommitStep implements CommitStep {

    private final Collection<FileStatus> pathsToDelete;
    private final Properties properties;
    private final URI fsUri;
    private final Optional<Path> parentDeletionLimit;

    public DeleteFileCommitStep(FileSystem fs, Path path, Properties properties) throws IOException {
        this(fs, Lists.newArrayList(fs.getFileStatus(path)), properties, Optional.<Path>absent());
    }

    public static DeleteFileCommitStep fromPaths(FileSystem fs, Collection<Path> paths, Properties properties)
            throws IOException {
        return new DeleteFileCommitStep(fs, toFileStatus(fs, paths), properties, Optional.<Path>absent());
    }

    public static DeleteFileCommitStep fromPaths(FileSystem fs, Collection<Path> paths, Properties properties,
            Path parentDeletionLimit) throws IOException {
        return new DeleteFileCommitStep(fs, toFileStatus(fs, paths), properties, Optional.of(parentDeletionLimit));
    }

    /**
     * @param fs {@link FileSystem} where files need to be deleted.
     * @param paths Collection of {@link FileStatus}es to deleted.
     * @param properties {@link Properties} object including {@link Trash} configuration.
     * @param parentDeletionLimit if present, will delete empty parent directories up to but not including this path. If
     *                            absent, will not delete empty parent directories.
     * @throws IOException
     */
    public DeleteFileCommitStep(FileSystem fs, Collection<FileStatus> paths, Properties properties,
            Optional<Path> parentDeletionLimit) throws IOException {
        this.fsUri = fs.getUri();
        this.pathsToDelete = paths;
        this.properties = properties;
        this.parentDeletionLimit = parentDeletionLimit;
    }

    private static List<FileStatus> toFileStatus(FileSystem fs, Collection<Path> paths) throws IOException {
        List<FileStatus> fileStatuses = Lists.newArrayList();
        for (Path path : paths) {
            fileStatuses.add(fs.getFileStatus(path));
        }
        return fileStatuses;
    }

    @Override
    public boolean isCompleted() throws IOException {
        for (FileStatus pathToDelete : this.pathsToDelete) {
            if (existsAndIsExpectedFile(pathToDelete)) {
                return false;
            }
        }
        return true;
    }

    @Override
    public void execute() throws IOException {
        Trash trash = TrashFactory.createTrash(getFS(), this.properties);
        Set<Path> parents = Sets.newHashSet();
        for (FileStatus pathToDelete : this.pathsToDelete) {
            if (existsAndIsExpectedFile(pathToDelete)) {
                trash.moveToTrash(pathToDelete.getPath());
                parents.add(pathToDelete.getPath().getParent());
            }
        }
        if (this.parentDeletionLimit.isPresent()) {
            for (Path parent : parents) {
                PathUtils.deleteEmptyParentDirectories(getFS(), this.parentDeletionLimit.get(), parent);
            }
        }
    }

    /**
     * Checks whether existing file in filesystem is the expected file (compares length and modificaiton time).
     */
    private boolean existsAndIsExpectedFile(FileStatus status) throws IOException {

        if (!getFS().exists(status.getPath())) {
            return false;
        }

        FileStatus currentFileStatus = getFS().getFileStatus(status.getPath());

        if (currentFileStatus.getLen() != status.getLen()
                || currentFileStatus.getModificationTime() > status.getModificationTime()) {
            return false;
        }

        return true;
    }

    private FileSystem getFS() throws IOException {
        return FileSystem.get(this.fsUri, new Configuration());
    }

    @Override
    public String toString() {
        return String.format("Delete the following files at %s: %s", this.fsUri,
                Iterables.toString(Iterables.transform(this.pathsToDelete, new Function<FileStatus, Path>() {
                    @Nullable
                    @Override
                    public Path apply(@Nullable FileStatus input) {
                        return input != null ? input.getPath() : null;
                    }
                })));
    }
}