private static Path writeTableDescriptor()

in hbase-hbck2/src/main/java/org/apache/hbase/HBCKFsTableDescriptors.java [334:393]
46 lines of code
9 McCabe index (conditional complexity)

  private static Path writeTableDescriptor(final FileSystem fs,
                                           final TableDescriptor htd, final Path tableDir,
                                           final FileStatus currentDescriptorFile)
    throws IOException {
    // Get temporary dir into which we'll first write a file to avoid half-written file phenomenon.
    // This directory is never removed to avoid removing it out from under a concurrent writer.
    Path tmpTableDir = new Path(tableDir, TMP_DIR);
    Path tableInfoDir = new Path(tableDir, TABLEINFO_DIR);

    // What is current sequenceid?  We read the current sequenceid from
    // the current file.  After we read it, another thread could come in and
    // compete with us writing out next version of file.  The below retries
    // should help in this case some but its hard to do guarantees in face of
    // concurrent schema edits.
    int currentSequenceId = currentDescriptorFile == null ? 0 :
      getTableInfoSequenceId(currentDescriptorFile.getPath());
    int newSequenceId = currentSequenceId;

    // Put arbitrary upperbound on how often we retry
    int retries = 10;
    int retrymax = currentSequenceId + retries;
    Path tableInfoDirPath = null;
    do {
      newSequenceId += 1;
      String filename = getTableInfoFileName(newSequenceId);
      Path tempPath = new Path(tmpTableDir, filename);
      if (fs.exists(tempPath)) {
        LOG.debug(tempPath + " exists; retrying up to " + retries + " times");
        continue;
      }
      tableInfoDirPath = new Path(tableInfoDir, filename);
      try {
        writeTD(fs, tempPath, htd);
        fs.mkdirs(tableInfoDirPath.getParent());
        if (!fs.rename(tempPath, tableInfoDirPath)) {
          throw new IOException("Failed rename of " + tempPath + " to " + tableInfoDirPath);
        }
        LOG.debug("Wrote into " + tableInfoDirPath);
      } catch (IOException ioe) {
        // fail-fast and get out of retry loop as user does not have privilege to write to hdfs
        // hence, no point in retrying
        if(ioe instanceof AccessControlException){
          throw ioe;
        }
        // Presume clash of names or something; go around again.
        LOG.debug("Failed write and/or rename; retrying", ioe);
        if (!HBCKFsUtils.deleteDirectory(fs, tempPath)) {
          LOG.warn("Failed cleanup of " + tempPath);
        }
        tableInfoDirPath = null;
        continue;
      }
      break;
    } while (newSequenceId < retrymax);
    if (tableInfoDirPath != null) {
      // if we succeeded, remove old table info files.
      deleteTableDescriptorFiles(fs, tableInfoDir, newSequenceId - 1);
    }
    return tableInfoDirPath;
  }