Package org.apache.flink.core.fs

Class SafetyNetWrapperFileSystem

java.lang.Object

org.apache.flink.core.fs.FileSystem

org.apache.flink.core.fs.SafetyNetWrapperFileSystem

All Implemented Interfaces:

IFileSystem, PathsCopyingFileSystem, WrappingProxy<FileSystem>

@Internal
public class SafetyNetWrapperFileSystem
extends FileSystem
implements WrappingProxy<FileSystem>, PathsCopyingFileSystem

This is a WrappingProxy around FileSystem which (i) wraps all opened streams as ClosingFSDataInputStream or ClosingFSDataOutputStream and (ii) registers them to a SafetyNetCloseableRegistry.

Streams obtained by this are therefore managed by the SafetyNetCloseableRegistry to prevent resource leaks from unclosed streams.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.flink.core.fs.FileSystem

FileSystem.FSKey, FileSystem.WriteMode

Nested classes/interfaces inherited from interface org.apache.flink.core.fs.PathsCopyingFileSystem

PathsCopyingFileSystem.CopyRequest

Constructor Summary

Constructors

Constructor	Description
SafetyNetWrapperFileSystem(FileSystem unsafeFileSystem, SafetyNetCloseableRegistry registry)

Method Summary

Modifier and Type	Method	Description
boolean	canCopyPaths(Path source, Path destination)	Tells if this FileSystem supports an optimised way to directly copy between given paths.
void	copyFiles(List<PathsCopyingFileSystem.CopyRequest> requests, ICloseableRegistry closeableRegistry)	List of PathsCopyingFileSystem.CopyRequest to copy in batch by this PathsCopyingFileSystem.
FSDataOutputStream	create(Path f, boolean overwrite, int bufferSize, short replication, long blockSize)	Opens an FSDataOutputStream at the indicated Path.
FSDataOutputStream	create(Path f, FileSystem.WriteMode overwrite)	Opens an FSDataOutputStream to a new file at the given path.
RecoverableWriter	createRecoverableWriter()	Creates a new RecoverableWriter.
boolean	delete(Path f, boolean recursive)	Delete a file.
boolean	exists(Path f)	Check if exists.
long	getDefaultBlockSize()	Return the number of bytes that large input files should be optimally be split into to minimize I/O time.
BlockLocation[]	getFileBlockLocations(FileStatus file, long start, long len)	Return an array containing hostnames, offset and size of portions of the given file.
FileStatus	getFileStatus(Path f)	Return a file status object that represents the path.
Path	getHomeDirectory()	Returns the path of the user's home directory in this file system.
URI	getUri()	Returns a URI whose scheme and authority identify this file system.
Path	getWorkingDirectory()	Returns the path of the file system's current working directory.
FileSystem	getWrappedDelegate()
boolean	initOutPathDistFS(Path outPath, FileSystem.WriteMode writeMode, boolean createDirectory)	Initializes output directories on distributed file systems according to the given write mode.
boolean	initOutPathLocalFS(Path outPath, FileSystem.WriteMode writeMode, boolean createDirectory)	Initializes output directories on local file systems according to the given write mode.
boolean	isDistributedFS()	Returns true if this is a distributed file system.
FileStatus[]	listStatus(Path f)	List the statuses of the files/directories in the given path if the path is a directory.
boolean	mkdirs(Path f)	Make the given file and all non-existent parents into directories.
FSDataInputStream	open(Path f)	Opens an FSDataInputStream at the indicated Path.
FSDataInputStream	open(Path f, int bufferSize)	Opens an FSDataInputStream at the indicated Path.
boolean	rename(Path src, Path dst)	Renames the file/directory src to dst.

Methods inherited from class org.apache.flink.core.fs.FileSystem

create, createRecoverableWriter, get, getDefaultFsUri, getLocalFileSystem, getUnguardedFileSystem, initialize, initialize

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.flink.core.fs.IFileSystem

createRecoverableWriter

Constructor Detail

SafetyNetWrapperFileSystem

public SafetyNetWrapperFileSystem(FileSystem unsafeFileSystem,
                                  SafetyNetCloseableRegistry registry)

Method Detail

copyFiles

public void copyFiles(List<PathsCopyingFileSystem.CopyRequest> requests,
                      ICloseableRegistry closeableRegistry)
               throws IOException

Description copied from interface: PathsCopyingFileSystem

List of PathsCopyingFileSystem.CopyRequest to copy in batch by this PathsCopyingFileSystem. In case of an exception some files might have been already copied fully or partially. Caller should clean this up. Copy can be interrupted by the CloseableRegistry.

Specified by:

copyFiles in interface PathsCopyingFileSystem

Throws:

IOException

canCopyPaths

public boolean canCopyPaths(Path source,
                            Path destination)
                     throws IOException

Description copied from interface: IFileSystem

Tells if this FileSystem supports an optimised way to directly copy between given paths. In other words if it implements PathsCopyingFileSystem.

At least one of, either source or destination belongs to this IFileSystem. One of them can point to the local file system. In other words this request can correspond to either: downloading a file from the remote file system, uploading a file to the remote file system or duplicating a file in the remote file system.

Specified by:

canCopyPaths in interface IFileSystem

Specified by:

canCopyPaths in interface PathsCopyingFileSystem

Parameters:

source - The path of the source file to duplicate

destination - The path where to duplicate the source file

Returns:

true, if this IFileSystem can perform this operation more quickly compared to the generic code path of using streams.

Throws:

IOException

getWorkingDirectory

public Path getWorkingDirectory()

Description copied from interface: IFileSystem

Returns the path of the file system's current working directory.

Specified by:

getWorkingDirectory in interface IFileSystem

Specified by:

getWorkingDirectory in class FileSystem

Returns:

the path of the file system's current working directory

getHomeDirectory

public Path getHomeDirectory()

Description copied from interface: IFileSystem

Returns the path of the user's home directory in this file system.

Specified by:

getHomeDirectory in interface IFileSystem

Specified by:

getHomeDirectory in class FileSystem

Returns:

the path of the user's home directory in this file system.

getUri

public URI getUri()

Description copied from interface: IFileSystem

Returns a URI whose scheme and authority identify this file system.

Specified by:

getUri in interface IFileSystem

Specified by:

getUri in class FileSystem

Returns:

a URI whose scheme and authority identify this file system

getFileStatus

public FileStatus getFileStatus(Path f)
                         throws IOException

Description copied from interface: IFileSystem

Return a file status object that represents the path.

Specified by:

getFileStatus in interface IFileSystem

Specified by:

getFileStatus in class FileSystem

Parameters:

f - The path we want information from

Returns:

a FileStatus object

Throws:

FileNotFoundException - when the path does not exist; IOException see specific implementation

IOException

createRecoverableWriter

public RecoverableWriter createRecoverableWriter()
                                          throws IOException

Description copied from interface: IFileSystem

Creates a new RecoverableWriter. A recoverable writer creates streams that can persist and recover their intermediate state. Persisting and recovering intermediate state is a core building block for writing to files that span multiple checkpoints.

The returned object can act as a shared factory to open and recover multiple streams.

This method is optional on file systems and various file system implementations may not support this method, throwing an UnsupportedOperationException.

Specified by:

createRecoverableWriter in interface IFileSystem

Overrides:

createRecoverableWriter in class FileSystem

Returns:

A RecoverableWriter for this file system.

Throws:

IOException - Thrown, if the recoverable writer cannot be instantiated.

getFileBlockLocations

public BlockLocation[] getFileBlockLocations(FileStatus file,
                                             long start,
                                             long len)
                                      throws IOException

Description copied from interface: IFileSystem

Return an array containing hostnames, offset and size of portions of the given file. For a nonexistent file or regions, null will be returned. This call is most helpful with DFS, where it returns hostnames of machines that contain the given file. The FileSystem will simply return an elt containing 'localhost'.

Specified by:

getFileBlockLocations in interface IFileSystem

Specified by:

getFileBlockLocations in class FileSystem

Throws:

IOException

open

public FSDataInputStream open(Path f,
                              int bufferSize)
                       throws IOException

Description copied from interface: IFileSystem

Opens an FSDataInputStream at the indicated Path.

Specified by:

open in interface IFileSystem

Specified by:

open in class FileSystem

Parameters:

f - the file name to open

bufferSize - the size of the buffer to be used.

Throws:

IOException

open

public FSDataInputStream open(Path f)
                       throws IOException

Description copied from interface: IFileSystem

Opens an FSDataInputStream at the indicated Path.

Specified by:

open in interface IFileSystem

Specified by:

open in class FileSystem

Parameters:

f - the file to open

Throws:

IOException

getDefaultBlockSize

public long getDefaultBlockSize()

Description copied from class: FileSystem

Return the number of bytes that large input files should be optimally be split into to minimize I/O time.

Overrides:

getDefaultBlockSize in class FileSystem

Returns:

the number of bytes that large input files should be optimally be split into to minimize I/O time

listStatus

public FileStatus[] listStatus(Path f)
                        throws IOException

Description copied from interface: IFileSystem

List the statuses of the files/directories in the given path if the path is a directory.

Specified by:

listStatus in interface IFileSystem

Specified by:

listStatus in class FileSystem

Parameters:

f - given path

Returns:

the statuses of the files/directories in the given path

Throws:

IOException

exists

public boolean exists(Path f)
               throws IOException

Description copied from interface: IFileSystem

Check if exists.

Specified by:

exists in interface IFileSystem

Overrides:

exists in class FileSystem

Parameters:

f - source file

Throws:

IOException

delete

public boolean delete(Path f,
                      boolean recursive)
               throws IOException

Description copied from interface: IFileSystem

Delete a file.

Specified by:

delete in interface IFileSystem

Specified by:

delete in class FileSystem

Parameters:

f - the path to delete

recursive - if path is a directory and set to true, the directory is deleted else throws an exception. In case of a file the recursive can be set to either true or false

Returns:

true if delete is successful, false otherwise

Throws:

IOException

mkdirs

public boolean mkdirs(Path f)
               throws IOException

Description copied from interface: IFileSystem

Make the given file and all non-existent parents into directories. Has the semantics of Unix 'mkdir -p'. Existence of the directory hierarchy is not an error.

Specified by:

mkdirs in interface IFileSystem

Specified by:

mkdirs in class FileSystem

Parameters:

f - the directory/directories to be created

Returns:

true if at least one new directory has been created, false otherwise

Throws:

IOException - thrown if an I/O error occurs while creating the directory

create

public FSDataOutputStream create(Path f,
                                 boolean overwrite,
                                 int bufferSize,
                                 short replication,
                                 long blockSize)
                          throws IOException

Description copied from class: FileSystem

Opens an FSDataOutputStream at the indicated Path.

This method is deprecated, because most of its parameters are ignored by most file systems. To control for example the replication factor and block size in the Hadoop Distributed File system, make sure that the respective Hadoop configuration file is either linked from the Flink configuration, or in the classpath of either Flink or the user code.

Overrides:

create in class FileSystem

Parameters:

f - the file name to open

overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.

bufferSize - the size of the buffer to be used.

replication - required block replication for the file.

blockSize - the size of the file blocks

Throws:

IOException - Thrown, if the stream could not be opened because of an I/O, or because a file already exists at that path and the write mode indicates to not overwrite the file.

create

public FSDataOutputStream create(Path f,
                                 FileSystem.WriteMode overwrite)
                          throws IOException

Description copied from interface: IFileSystem

Opens an FSDataOutputStream to a new file at the given path.

If the file already exists, the behavior depends on the given WriteMode. If the mode is set to FileSystem.WriteMode.NO_OVERWRITE, then this method fails with an exception.

Specified by:

create in interface IFileSystem

Specified by:

create in class FileSystem

Parameters:

f - The file path to write to

overwrite - The action to take if a file or directory already exists at the given path.

Returns:

The stream to the new file at the target path.

Throws:

IOException - Thrown, if the stream could not be opened because of an I/O, or because a file already exists at that path and the write mode indicates to not overwrite the file.

rename

public boolean rename(Path src,
                      Path dst)
               throws IOException

Description copied from interface: IFileSystem

Renames the file/directory src to dst.

Specified by:

rename in interface IFileSystem

Specified by:

rename in class FileSystem

Parameters:

src - the file/directory to rename

dst - the new name of the file/directory

Returns:

true if the renaming was successful, false otherwise

Throws:

IOException

initOutPathLocalFS

public boolean initOutPathLocalFS(Path outPath,
                                  FileSystem.WriteMode writeMode,
                                  boolean createDirectory)
                           throws IOException

Description copied from interface: IFileSystem

Initializes output directories on local file systems according to the given write mode.

• WriteMode.NO_OVERWRITE & parallel output:
  • A directory is created if the output path does not exist.
  • An existing directory is reused, files contained in the directory are NOT deleted.
  • An existing file raises an exception.
• WriteMode.NO_OVERWRITE & NONE parallel output:
  • An existing file or directory raises an exception.
• WriteMode.OVERWRITE & parallel output:
  • A directory is created if the output path does not exist.
  • An existing directory is reused, files contained in the directory are NOT deleted.
  • An existing file is deleted and replaced by a new directory.
• WriteMode.OVERWRITE & NONE parallel output:
  • An existing file or directory (and all its content) is deleted

Files contained in an existing directory are not deleted, because multiple instances of a DataSinkTask might call this function at the same time and hence might perform concurrent delete operations on the file system (possibly deleting output files of concurrently running tasks). Since concurrent DataSinkTasks are not aware of each other, coordination of delete and create operations would be difficult.

Specified by:

initOutPathLocalFS in interface IFileSystem

Overrides:

initOutPathLocalFS in class FileSystem

Parameters:

outPath - Output path that should be prepared.

writeMode - Write mode to consider.

createDirectory - True, to initialize a directory at the given path, false to prepare space for a file.

Returns:

True, if the path was successfully prepared, false otherwise.

Throws:

IOException - Thrown, if any of the file system access operations failed.

initOutPathDistFS

public boolean initOutPathDistFS(Path outPath,
                                 FileSystem.WriteMode writeMode,
                                 boolean createDirectory)
                          throws IOException

Description copied from interface: IFileSystem

Initializes output directories on distributed file systems according to the given write mode.

WriteMode.NO_OVERWRITE & parallel output: - A directory is created if the output path does not exist. - An existing file or directory raises an exception.

WriteMode.NO_OVERWRITE & NONE parallel output: - An existing file or directory raises an exception.

WriteMode.OVERWRITE & parallel output: - A directory is created if the output path does not exist. - An existing directory and its content is deleted and a new directory is created. - An existing file is deleted and replaced by a new directory.

WriteMode.OVERWRITE & NONE parallel output: - An existing file or directory is deleted and replaced by a new directory.

Specified by:

initOutPathDistFS in interface IFileSystem

Overrides:

initOutPathDistFS in class FileSystem

Parameters:

outPath - Output path that should be prepared.

writeMode - Write mode to consider.

createDirectory - True, to initialize a directory at the given path, false otherwise.

Returns:

True, if the path was successfully prepared, false otherwise.

Throws:

IOException - Thrown, if any of the file system access operations failed.

isDistributedFS

public boolean isDistributedFS()

Description copied from interface: IFileSystem

Returns true if this is a distributed file system. A distributed file system here means that the file system is shared among all Flink processes that participate in a cluster or job and that all these processes can see the same files.

Specified by:

isDistributedFS in interface IFileSystem

Specified by:

isDistributedFS in class FileSystem

Returns:

True, if this is a distributed file system, false otherwise.

getWrappedDelegate

public FileSystem getWrappedDelegate()

Specified by:

getWrappedDelegate in interface WrappingProxy<FileSystem>