/**
   * Load grid configuration for specified node type.
   *
   * @param type Node type to load configuration for.
   * @return Grid configuration for specified node type.
   */
  static IgniteConfiguration getConfig(String type) {
    String path = NODE_CFG.get(type);

    if (path == null) throw new IllegalArgumentException("Unsupported node type: " + type);

    URL url = U.resolveIgniteUrl(path);

    BeanFactory ctx = new FileSystemXmlApplicationContext(url.toString());

    return (IgniteConfiguration) ctx.getBean("grid.cfg");
  }
  /**
   * Resolve IGFS profiler logs directory.
   *
   * @param igfs IGFS instance to resolve logs dir for.
   * @return {@link Path} to log dir or {@code null} if not found.
   * @throws IgniteCheckedException if failed to resolve.
   */
  public static Path resolveIgfsProfilerLogsDir(IgniteFileSystem igfs)
      throws IgniteCheckedException {
    String logsDir;

    if (igfs instanceof IgfsEx) logsDir = ((IgfsEx) igfs).clientLogDirectory();
    else if (igfs == null)
      throw new IgniteCheckedException(
          "Failed to get profiler log folder (IGFS instance not found)");
    else
      throw new IgniteCheckedException(
          "Failed to get profiler log folder (unexpected IGFS instance type)");

    URL logsDirUrl = U.resolveIgniteUrl(logsDir != null ? logsDir : DFLT_IGFS_LOG_DIR);

    return logsDirUrl != null ? new File(logsDirUrl.getPath()).toPath() : null;
  }
  /**
   * Check how prefetch override works.
   *
   * @throws Exception IF failed.
   */
  public void testOpenPrefetchOverride() throws Exception {
    create(igfsSecondary, paths(DIR, SUBDIR), paths(FILE));

    // Write enough data to the secondary file system.
    final int blockSize = IGFS_BLOCK_SIZE;

    IgfsOutputStream out = igfsSecondary.append(FILE, false);

    int totalWritten = 0;

    while (totalWritten < blockSize * 2 + chunk.length) {
      out.write(chunk);

      totalWritten += chunk.length;
    }

    out.close();

    awaitFileClose(igfsSecondary.asSecondary(), FILE);

    // Instantiate file system with overridden "seq reads before prefetch" property.
    Configuration cfg = new Configuration();

    cfg.addResource(U.resolveIgniteUrl(PRIMARY_CFG));

    int seqReads = SEQ_READS_BEFORE_PREFETCH + 1;

    cfg.setInt(String.format(PARAM_IGFS_SEQ_READS_BEFORE_PREFETCH, "igfs:grid@"), seqReads);

    FileSystem fs = FileSystem.get(new URI(PRIMARY_URI), cfg);

    // Read the first two blocks.
    Path fsHome = new Path(PRIMARY_URI);
    Path dir = new Path(fsHome, DIR.name());
    Path subdir = new Path(dir, SUBDIR.name());
    Path file = new Path(subdir, FILE.name());

    FSDataInputStream fsIn = fs.open(file);

    final byte[] readBuf = new byte[blockSize * 2];

    fsIn.readFully(0, readBuf, 0, readBuf.length);

    // Wait for a while for prefetch to finish (if any).
    IgfsMetaManager meta = igfs.context().meta();

    IgfsFileInfo info = meta.info(meta.fileId(FILE));

    IgfsBlockKey key = new IgfsBlockKey(info.id(), info.affinityKey(), info.evictExclude(), 2);

    IgniteCache<IgfsBlockKey, byte[]> dataCache =
        igfs.context().kernalContext().cache().jcache(igfs.configuration().getDataCacheName());

    for (int i = 0; i < 10; i++) {
      if (dataCache.containsKey(key)) break;
      else U.sleep(100);
    }

    fsIn.close();

    // Remove the file from the secondary file system.
    igfsSecondary.delete(FILE, false);

    // Try reading the third block. Should fail.
    GridTestUtils.assertThrows(
        log,
        new Callable<Object>() {
          @Override
          public Object call() throws Exception {
            IgfsInputStream in0 = igfs.open(FILE);

            in0.seek(blockSize * 2);

            try {
              in0.read(readBuf);
            } finally {
              U.closeQuiet(in0);
            }

            return null;
          }
        },
        IOException.class,
        "Failed to read data due to secondary file system exception: /dir/subdir/file");
  }