flink-runtime/src/main/java/org/apache/flink/runtime/state/LocalRecoveryDirectoryProviderImpl.java

/*
 * 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.state;

import org.apache.flink.annotation.VisibleForTesting;
import org.apache.flink.api.common.JobID;
import org.apache.flink.runtime.jobgraph.JobVertexID;
import org.apache.flink.util.Preconditions;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;

import java.io.File;
import java.nio.file.Paths;
import java.util.Arrays;

/** Implementation of {@link LocalRecoveryDirectoryProvider}. */
public class LocalRecoveryDirectoryProviderImpl implements LocalRecoveryDirectoryProvider {

    /** Serial version. */
    private static final long serialVersionUID = 1L;

    /** Logger for this class. */
    private static final Logger LOG =
            LoggerFactory.getLogger(LocalRecoveryDirectoryProviderImpl.class);

    /** All available root directories that this can potentially deliver. */
    @Nonnull private final File[] allocationBaseDirs;

    /** JobID of the owning job. */
    @Nonnull private final JobID jobID;

    /** JobVertexID of the owning task. */
    @Nonnull private final JobVertexID jobVertexID;

    /** Index of the owning subtask. */
    @Nonnegative private final int subtaskIndex;

    public LocalRecoveryDirectoryProviderImpl(
            File allocationBaseDir,
            @Nonnull JobID jobID,
            @Nonnull JobVertexID jobVertexID,
            @Nonnegative int subtaskIndex) {
        this(new File[] {allocationBaseDir}, jobID, jobVertexID, subtaskIndex);
    }

    public LocalRecoveryDirectoryProviderImpl(
            @Nonnull File[] allocationBaseDirs,
            @Nonnull JobID jobID,
            @Nonnull JobVertexID jobVertexID,
            @Nonnegative int subtaskIndex) {

        Preconditions.checkArgument(allocationBaseDirs.length > 0);
        this.allocationBaseDirs = allocationBaseDirs;
        this.jobID = jobID;
        this.jobVertexID = jobVertexID;
        this.subtaskIndex = subtaskIndex;

        for (File allocationBaseDir : allocationBaseDirs) {
            Preconditions.checkNotNull(allocationBaseDir);
            allocationBaseDir.mkdirs();
        }
    }

    @Override
    public File allocationBaseDirectory(long checkpointId) {
        return selectAllocationBaseDirectory(
                (((int) checkpointId) & Integer.MAX_VALUE) % allocationBaseDirs.length);
    }

    @Override
    public File subtaskBaseDirectory(long checkpointId) {
        return new File(allocationBaseDirectory(checkpointId), subtaskDirString());
    }

    @Override
    public File subtaskSpecificCheckpointDirectory(long checkpointId) {
        return new File(subtaskBaseDirectory(checkpointId), checkpointDirString(checkpointId));
    }

    @Override
    public File selectAllocationBaseDirectory(int idx) {
        return allocationBaseDirs[idx];
    }

    @Override
    public File selectSubtaskBaseDirectory(int idx) {
        return new File(selectAllocationBaseDirectory(idx), subtaskDirString());
    }

    @Override
    public int allocationBaseDirsCount() {
        return allocationBaseDirs.length;
    }

    @Override
    public String toString() {
        return "LocalRecoveryDirectoryProvider{"
                + "rootDirectories="
                + Arrays.toString(allocationBaseDirs)
                + ", jobID="
                + jobID
                + ", jobVertexID="
                + jobVertexID
                + ", subtaskIndex="
                + subtaskIndex
                + '}';
    }

    @VisibleForTesting
    String subtaskDirString() {
        return Paths.get("jid_" + jobID, "vtx_" + jobVertexID + "_sti_" + subtaskIndex).toString();
    }

    @VisibleForTesting
    String checkpointDirString(long checkpointId) {
        return "chk_" + checkpointId;
    }
}