/**
* Attempts to create a file. Overwrite will not succeed if the path exists and is a folder.
*
* @param path path to create
* @param permission permissions of the created file/folder
* @param overwrite overwrite if file exists
* @param bufferSize the size in bytes of the buffer to be used
* @param replication under filesystem replication factor
* @param blockSize block size in bytes
* @param progress queryable progress
* @return an {@link FSDataOutputStream} created at the indicated path of a file
* @throws IOException if overwrite is not specified and the path already exists or if the path is
* a folder
*/
@Override
public FSDataOutputStream create(
Path path,
FsPermission permission,
boolean overwrite,
int bufferSize,
short replication,
long blockSize,
Progressable progress)
throws IOException {
LOG.info(
"create({}, {}, {}, {}, {}, {}, {})",
path,
permission,
overwrite,
bufferSize,
replication,
blockSize,
progress);
if (mStatistics != null) {
mStatistics.incrementWriteOps(1);
}
// Check whether the file already exists, and delete it if overwrite is true
AlluxioURI uri = new AlluxioURI(HadoopUtils.getPathWithoutScheme(path));
try {
if (mFileSystem.exists(uri)) {
if (!overwrite) {
throw new IOException(ExceptionMessage.FILE_ALREADY_EXISTS.getMessage(uri));
}
if (mFileSystem.getStatus(uri).isFolder()) {
throw new IOException(ExceptionMessage.FILE_CREATE_IS_DIRECTORY.getMessage(uri));
}
mFileSystem.delete(uri);
}
} catch (AlluxioException e) {
throw new IOException(e);
}
// The file no longer exists at this point, so we can create it
CreateFileOptions options =
CreateFileOptions.defaults()
.setBlockSizeBytes(blockSize)
.setMode(new Mode(permission.toShort()));
try {
FileOutStream outStream = mFileSystem.createFile(uri, options);
return new FSDataOutputStream(outStream, mStatistics);
} catch (AlluxioException e) {
throw new IOException(e);
}
}
/**
* Attempts to delete the file or directory with the specified path.
*
* @param path path to delete
* @param recursive if true, will attempt to delete all children of the path
* @return true if one or more files/directories were deleted; false otherwise
* @throws IOException if the path failed to be deleted due to some constraint (ie. non empty
* directory with recursive flag disabled)
*/
@Override
public boolean delete(Path path, boolean recursive) throws IOException {
LOG.info("delete({}, {})", path, recursive);
if (mStatistics != null) {
mStatistics.incrementWriteOps(1);
}
AlluxioURI uri = new AlluxioURI(HadoopUtils.getPathWithoutScheme(path));
DeleteOptions options = DeleteOptions.defaults().setRecursive(recursive);
try {
mFileSystem.delete(uri, options);
return true;
} catch (InvalidPathException | FileDoesNotExistException e) {
LOG.error("delete failed: {}", e.getMessage());
return false;
} catch (AlluxioException e) {
throw new IOException(e);
}
}
/**
* Entry point for the {@link MultiMount} program.
*
* @param args command-line arguments
*/
public static void main(String[] args) {
if (args.length != 1) {
System.err.println("Usage: ./bin/alluxio runClass alluxio.examples.MultiMount <HDFS_URL>");
System.exit(-1);
}
AlluxioURI mntPath = new AlluxioURI("/mnt");
AlluxioURI s3Mount = new AlluxioURI("/mnt/s3");
AlluxioURI inputPath = new AlluxioURI("/mnt/s3/hello.txt");
AlluxioURI s3Path = new AlluxioURI("s3n://alluxio-demo/");
AlluxioURI hdfsMount = new AlluxioURI("/mnt/hdfs");
AlluxioURI outputPath = new AlluxioURI("/mnt/hdfs/hello.txt");
AlluxioURI hdfsPath = new AlluxioURI(args[0]);
FileSystem fileSystem = FileSystem.Factory.get();
try {
// Make sure mount directory exists.
if (!fileSystem.exists(mntPath)) {
System.out.print("creating " + mntPath + " ... ");
fileSystem.createDirectory(mntPath);
System.out.println("done");
}
// Make sure the S3 mount point does not exist.
if (fileSystem.exists(s3Mount)) {
System.out.print("unmounting " + s3Mount + " ... ");
fileSystem.unmount(s3Mount);
System.out.println("done");
}
// Make sure the HDFS mount point does not exist.
if (fileSystem.exists(hdfsMount)) {
System.out.print("unmounting " + hdfsMount + " ... ");
fileSystem.unmount(hdfsMount);
System.out.println("done");
}
// Mount S3.
System.out.print("mounting " + s3Path + " to " + s3Mount + " ... ");
fileSystem.mount(s3Mount, s3Path);
System.out.println("done");
// Mount HDFS.
System.out.print("mounting " + hdfsPath + " to " + hdfsMount + " ... ");
fileSystem.mount(hdfsMount, hdfsPath);
System.out.println("done");
// Make sure output file does not exist.
if (fileSystem.exists(outputPath)) {
System.out.print("deleting " + outputPath + " ... ");
fileSystem.delete(outputPath);
System.out.println("done");
}
// Open the input stream.
System.out.print("opening " + inputPath + " ... ");
FileInStream is = fileSystem.openFile(inputPath);
System.out.println("done");
// Open the output stream, setting the write type to make sure result is persisted.
System.out.print("opening " + outputPath + " ... ");
CreateFileOptions options =
CreateFileOptions.defaults().setWriteType(WriteType.CACHE_THROUGH);
FileOutStream os = fileSystem.createFile(outputPath, options);
System.out.println("done");
// Copy the data
System.out.print("transferring data from " + inputPath + " to " + outputPath + " ... ");
IOUtils.copy(is, os);
System.out.println("done");
// Close the input stream.
System.out.print("closing " + inputPath + " ... ");
is.close();
System.out.println("done");
// Close the output stream.
System.out.print("closing " + outputPath + " ... ");
os.close();
System.out.println("done");
} catch (Exception e) {
System.out.println("fail");
e.printStackTrace();
} finally {
// Make sure the S3 mount point is removed.
try {
if (fileSystem.exists(s3Mount)) {
System.out.print("unmounting " + s3Mount + " ... ");
fileSystem.unmount(s3Mount);
System.out.println("done");
}
} catch (Exception e) {
System.out.println("fail");
e.printStackTrace();
}
// Make sure the HDFS mount point is removed.
try {
if (fileSystem.exists(hdfsMount)) {
System.out.print("unmounting " + hdfsMount + " ... ");
fileSystem.unmount(hdfsMount);
System.out.println("done");
}
} catch (Exception e) {
System.out.println("fail");
e.printStackTrace();
}
}
}