content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.worker.block;
  
  import alluxio.client.file.FileSystem;
  import alluxio.client.file.FileSystemContext;
  import alluxio.fuse.AlluxioFuse;
  import alluxio.fuse.FuseUmountable;
  import alluxio.fuse.options.FuseOptions;
  
  import com.google.common.io.Closer;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.Closeable;
  import java.io.IOException;
  
  /**
   * The Fuse manager that is responsible for managing the Fuse application lifecycle.
   */
  public class FuseManager implements Closeable {
    private static final Logger LOG = LoggerFactory.getLogger(FuseManager.class);
    private final FileSystemContext mFsContext;
    /** Use to umount Fuse application during stop. */
    private FuseUmountable mFuseUmountable;
    /** Use to close resources during stop. */
    private final Closer mResourceCloser;
  
    /**
     * Constructs a new {@link FuseManager}.
     *
     * @param fsContext fs context
     */
    public FuseManager(FileSystemContext fsContext) {
      mFsContext = fsContext;
      mResourceCloser = Closer.create();
    }
  
    /**
     * Starts mounting the internal Fuse applications.
     */
    public void start() {
      try {
        // TODO(lu) consider launching fuse in a separate thread as blocking operation
        // so that we can know about the fuse application status
        FileSystem fileSystem = mResourceCloser.register(FileSystem.Factory.create(mFsContext));
        mFuseUmountable = AlluxioFuse.launchFuse(
            mFsContext, fileSystem, FuseOptions.create(mFsContext.getClusterConf()), false);
      } catch (Throwable throwable) {
        // TODO(lu) for already mounted application, unmount first and then remount
        LOG.error("Failed to launch worker internal Fuse application", throwable);
      }
    }
  
    @Override
    public void close() throws IOException {
      if (mFuseUmountable != null) {
        try {
          mFuseUmountable.umount(true);
        } catch (Throwable throwable) {
          LOG.error("Failed to umount worker internal Fuse application", throwable);
        }
      }
      mResourceCloser.close();
    }
  }
  