org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils#getSnapshotsDir ( )源码实例Demo

/**
 * Create a snapshot file cache for all snapshots under the specified [root]/.snapshot on the
 * filesystem
 * @param fs {@link FileSystem} where the snapshots are stored
 * @param rootDir hbase root directory
 * @param workingFs {@link FileSystem} where ongoing snapshot mainifest files are stored
 * @param workingDir Location to store ongoing snapshot manifest files
 * @param cacheRefreshPeriod period (ms) with which the cache should be refreshed
 * @param cacheRefreshDelay amount of time to wait for the cache to be refreshed
 * @param refreshThreadName name of the cache refresh thread
 * @param inspectSnapshotFiles Filter to apply to each snapshot to extract the files.
 */
public SnapshotFileCache(FileSystem fs, Path rootDir, FileSystem workingFs, Path workingDir,
  long cacheRefreshPeriod, long cacheRefreshDelay, String refreshThreadName,
  SnapshotFileInspector inspectSnapshotFiles) {
  this.fs = fs;
  this.workingFs = workingFs;
  this.workingSnapshotDir = workingDir;
  this.fileInspector = inspectSnapshotFiles;
  this.snapshotDir = SnapshotDescriptionUtils.getSnapshotsDir(rootDir);
  // periodically refresh the file cache to make sure we aren't superfluously saving files.
  this.refreshTimer = new Timer(refreshThreadName, true);
  this.refreshTimer.scheduleAtFixedRate(new RefreshCacheTask(), cacheRefreshDelay,
    cacheRefreshPeriod);
}
 

protected static void initCommon() throws Exception {
  UTIL.startMiniDFSCluster(1);
  fs = UTIL.getDFSCluster().getFileSystem();
  rootDir = UTIL.getDefaultRootDirPath();
  snapshotDir = SnapshotDescriptionUtils.getSnapshotsDir(rootDir);
  conf = UTIL.getConfiguration();
}
 

/**
 * Called at startup, to verify if snapshot operation is supported, and to avoid
 * starting the master if there're snapshots present but the cleaners needed are missing.
 * Otherwise we can end up with snapshot data loss.
 * @param conf The {@link Configuration} object to use
 * @param mfs The MasterFileSystem to use
 * @throws IOException in case of file-system operation failure
 * @throws UnsupportedOperationException in case cleaners are missing and
 *         there're snapshot in the system
 */
private void checkSnapshotSupport(final Configuration conf, final MasterFileSystem mfs)
    throws IOException, UnsupportedOperationException {
  // Verify if snapshot is disabled by the user
  String enabled = conf.get(HBASE_SNAPSHOT_ENABLED);
  boolean snapshotEnabled = conf.getBoolean(HBASE_SNAPSHOT_ENABLED, false);
  boolean userDisabled = (enabled != null && enabled.trim().length() > 0 && !snapshotEnabled);

  // Extract cleaners from conf
  Set<String> hfileCleaners = new HashSet<>();
  String[] cleaners = conf.getStrings(HFileCleaner.MASTER_HFILE_CLEANER_PLUGINS);
  if (cleaners != null) Collections.addAll(hfileCleaners, cleaners);

  Set<String> logCleaners = new HashSet<>();
  cleaners = conf.getStrings(HConstants.HBASE_MASTER_LOGCLEANER_PLUGINS);
  if (cleaners != null) Collections.addAll(logCleaners, cleaners);

  // check if an older version of snapshot directory was present
  Path oldSnapshotDir = new Path(mfs.getRootDir(), HConstants.OLD_SNAPSHOT_DIR_NAME);
  FileSystem fs = mfs.getFileSystem();
  List<SnapshotDescription> ss = getCompletedSnapshots(new Path(rootDir, oldSnapshotDir), false);
  if (ss != null && !ss.isEmpty()) {
    LOG.error("Snapshots from an earlier release were found under: " + oldSnapshotDir);
    LOG.error("Please rename the directory as " + HConstants.SNAPSHOT_DIR_NAME);
  }

  // If the user has enabled the snapshot, we force the cleaners to be present
  // otherwise we still need to check if cleaners are enabled or not and verify
  // that there're no snapshot in the .snapshot folder.
  if (snapshotEnabled) {
    // Inject snapshot cleaners, if snapshot.enable is true
    hfileCleaners.add(SnapshotHFileCleaner.class.getName());
    hfileCleaners.add(HFileLinkCleaner.class.getName());
    // If sync acl to HDFS feature is enabled, then inject the cleaner
    if (SnapshotScannerHDFSAclHelper.isAclSyncToHdfsEnabled(conf)) {
      hfileCleaners.add(SnapshotScannerHDFSAclCleaner.class.getName());
    }

    // Set cleaners conf
    conf.setStrings(HFileCleaner.MASTER_HFILE_CLEANER_PLUGINS,
      hfileCleaners.toArray(new String[hfileCleaners.size()]));
    conf.setStrings(HConstants.HBASE_MASTER_LOGCLEANER_PLUGINS,
      logCleaners.toArray(new String[logCleaners.size()]));
  } else {
    // Verify if cleaners are present
    snapshotEnabled =
      hfileCleaners.contains(SnapshotHFileCleaner.class.getName()) &&
      hfileCleaners.contains(HFileLinkCleaner.class.getName());

    // Warn if the cleaners are enabled but the snapshot.enabled property is false/not set.
    if (snapshotEnabled) {
      LOG.warn("Snapshot log and hfile cleaners are present in the configuration, " +
        "but the '" + HBASE_SNAPSHOT_ENABLED + "' property " +
        (userDisabled ? "is set to 'false'." : "is not set."));
    }
  }

  // Mark snapshot feature as enabled if cleaners are present and user has not disabled it.
  this.isSnapshotSupported = snapshotEnabled && !userDisabled;

  // If cleaners are not enabled, verify that there're no snapshot in the .snapshot folder
  // otherwise we end up with snapshot data loss.
  if (!snapshotEnabled) {
    LOG.info("Snapshot feature is not enabled, missing log and hfile cleaners.");
    Path snapshotDir = SnapshotDescriptionUtils.getSnapshotsDir(mfs.getRootDir());
    if (fs.exists(snapshotDir)) {
      FileStatus[] snapshots = CommonFSUtils.listStatus(fs, snapshotDir,
        new SnapshotDescriptionUtils.CompletedSnaphotDirectoriesFilter(fs));
      if (snapshots != null) {
        LOG.error("Snapshots are present, but cleaners are not enabled.");
        checkSnapshotSupport();
      }
    }
  }
}