org.apache.hadoop.fs.azure

Class NativeAzureFileSystem

java.lang.Object

org.apache.hadoop.conf.Configured

org.apache.hadoop.fs.FileSystem

org.apache.hadoop.fs.azure.NativeAzureFileSystem

All Implemented Interfaces:

Closeable, AutoCloseable, Configurable

@InterfaceAudience.Public
@InterfaceStability.Stable
public class NativeAzureFileSystem
extends FileSystem

A FileSystem for reading and writing files stored on Windows Azure. This implementation is blob-based and stores files on Azure in their native form so they can be read by other Azure tools.

Field Summary

Fields

Modifier and Type	Field and Description
static String	APPEND_SUPPORT_ENABLE_PROPERTY_NAME
static String	AZURE_CHMOD_USERLIST_PROPERTY_NAME Configuration property used to specify list of users that can perform chmod operation when authorization is enabled in WASB.
static String	AZURE_CHOWN_USERLIST_PROPERTY_NAME Configuration property used to specify list of users that can perform chown operation when authorization is enabled in WASB.
static String	AZURE_DAEMON_USERLIST_PROPERTY_NAME Configuration property used to specify list of daemon users that can perform chmod operation when authorization is enabled in WASB.
static String	AZURE_DELETE_THREADS The configuration property to set number of threads to be used for delete operation.
static String	AZURE_RENAME_THREADS The configuration property to set number of threads to be used for rename operation.
static int	DEFAULT_AZURE_DELETE_THREADS The default number of threads to be used for delete operation.
static int	DEFAULT_AZURE_RENAME_THREADS The default number of threads to be used for rename operation.
static String	KEY_AZURE_AUTHORIZATION Configuration key to enable authorization support in WASB.
static org.slf4j.Logger	LOG
static String	SKIP_AZURE_METRICS_PROPERTY_NAME

Fields inherited from class org.apache.hadoop.fs.FileSystem

DEFAULT_FS, FS_DEFAULT_NAME_KEY, SHUTDOWN_HOOK_PRIORITY, statistics, TRASH_PREFIX, USER_HOME_PREFIX

Constructor Summary

Constructors

Constructor and Description
NativeAzureFileSystem()
NativeAzureFileSystem(org.apache.hadoop.fs.azure.NativeFileSystemStore store)

Method Summary

Methods

Modifier and Type	Method and Description
void	access(Path path, FsAction mode) Checks if the user can access a path.
org.apache.hadoop.fs.azure.SelfRenewingLease	acquireLease(Path path) Get a self-renewing lease on the specified file.
FSDataOutputStream	append(Path f, int bufferSize, Progressable progress) This optional operation is not yet supported.
protected void	checkPath(Path path) Check that a Path belongs to this FileSystem.
void	close() Close this FileSystem instance.
FSDataOutputStream	create(Path f, FsPermission permission, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress) Create an FSDataOutputStream at the indicated Path with write-progress reporting.
protected FSDataOutputStream	createInternal(Path f, FsPermission permission, boolean overwrite, org.apache.hadoop.fs.azure.SelfRenewingLease parentFolderLease) This is the version of the create call that is meant for internal usage.
FSDataOutputStream	createNonRecursive(Path f, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress) Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
FSDataOutputStream	createNonRecursive(Path f, FsPermission permission, boolean overwrite, int bufferSize, short replication, long blockSize, Progressable progress) Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
FSDataOutputStream	createNonRecursive(Path f, FsPermission permission, EnumSet<CreateFlag> flags, int bufferSize, short replication, long blockSize, Progressable progress) Opens an FSDataOutputStream at the indicated Path with write-progress reporting.
boolean	delete(Path path) Deprecated.
boolean	delete(Path f, boolean recursive) Delete a file.
boolean	delete(Path f, boolean recursive, boolean skipParentFolderLastModifiedTimeUpdate) Delete the specified file or folder.
void	deleteFilesWithDanglingTempData(Path root) Looks under the given root path for any blob that are left "dangling", meaning that they are place-holder blobs that we created while we upload the data to a temporary blob, but for some reason we crashed in the middle of the upload and left them there.
protected boolean	existsInternal(Path f) Checks if a given path exists in the filesystem.
protected void	finalize()
Token<?>	getDelegationToken(String renewer) Get a delegation token from remote service endpoint if 'fs.azure.enable.kerberos.support' is set to 'true'.
FileStatus	getFileStatus(Path f) Return a file status object that represents the path.
Path	getHomeDirectory() Return the current user's home directory in this FileSystem.
AzureFileSystemInstrumentation	getInstrumentation() Gets the metrics source for this file system.
String	getOwnerForPath(Path absolutePath)
String	getScheme() Return the protocol scheme for this FileSystem.
org.apache.hadoop.fs.azure.AzureNativeFileSystemStore	getStore() For unit test purposes, retrieves the AzureNativeFileSystemStore store backing this file system.
org.apache.hadoop.fs.azure.AzureFileSystemThreadPoolExecutor	getThreadPoolExecutor(int threadCount, String threadNamePrefix, String operation, String key, String config)
URI	getUri() Returns a URI which identifies this FileSystem.
Path	getWorkingDirectory() Get the current working directory for the given FileSystem
void	initialize(URI uri, Configuration conf) Initialize a FileSystem.
FileStatus[]	listStatus(Path f) Retrieve the status of a given path if it is a file, or of all the contained files if it is a directory.
Path	makeAbsolute(Path path) Get the absolute version of the path (fully qualified).
boolean	mkdirs(Path f, FsPermission permission) Make the given file and all non-existent parents into directories.
boolean	mkdirs(Path f, FsPermission permission, boolean noUmask)
static String	newMetricsSourceName() Creates a new metrics source name that's unique within this process.
FSDataInputStream	open(Path f, int bufferSize) Opens an FSDataInputStream at the indicated Path.
String	pathToKey(Path path) Convert the path to a key.
void	recoverFilesWithDanglingTempData(Path root, Path destination) Looks under the given root path for any blob that are left "dangling", meaning that they are place-holder blobs that we created while we upload the data to a temporary blob, but for some reason we crashed in the middle of the upload and left them there.
boolean	rename(Path src, Path dst) Renames Path src to Path dst.
void	setOwner(Path p, String username, String groupname) Set owner of a path (i.e.
void	setPermission(Path p, FsPermission permission) Set permission of a path.
void	setWorkingDirectory(Path newDir) Set the working directory to the given directory.
void	updateWasbAuthorizer(org.apache.hadoop.fs.azure.WasbAuthorizerInterface authorizer)

Methods inherited from class org.apache.hadoop.fs.FileSystem

addDelegationTokens, append, append, appendFile, areSymlinksEnabled, cancelDeleteOnExit, canonicalizeUri, clearStatistics, closeAll, closeAllForUGI, completeLocalOutput, concat, copyFromLocalFile, copyFromLocalFile, copyFromLocalFile, copyFromLocalFile, copyToLocalFile, copyToLocalFile, copyToLocalFile, create, create, create, create, create, create, create, create, create, create, create, create, createFile, createNewFile, createSnapshot, createSnapshot, createSymlink, deleteOnExit, deleteSnapshot, enableSymlinks, exists, fixRelativePart, get, get, get, getAclStatus, getAllStatistics, getAllStoragePolicies, getBlockSize, getCanonicalServiceName, getCanonicalUri, getContentSummary, getDefaultBlockSize, getDefaultBlockSize, getDefaultPort, getDefaultReplication, getDefaultReplication, getDefaultUri, getFileBlockLocations, getFileBlockLocations, getFileChecksum, getFileChecksum, getFileLinkStatus, getFileSystemClass, getFSofPath, getGlobalStorageStatistics, getInitialWorkingDirectory, getLength, getLinkTarget, getLocal, getName, getNamed, getQuotaUsage, getReplication, getServerDefaults, getServerDefaults, getStatistics, getStatistics, getStatus, getStatus, getStoragePolicy, getStorageStatistics, getTrashRoot, getTrashRoots, getUsed, getUsed, getXAttr, getXAttrs, getXAttrs, globStatus, globStatus, isDirectory, isFile, listCorruptFileBlocks, listFiles, listLocatedStatus, listLocatedStatus, listStatus, listStatus, listStatus, listStatusIterator, listXAttrs, makeQualified, mkdirs, mkdirs, modifyAclEntries, moveFromLocalFile, moveFromLocalFile, moveToLocalFile, newInstance, newInstance, newInstance, newInstanceLocal, open, primitiveCreate, primitiveMkdir, primitiveMkdir, printStatistics, processDeleteOnExit, removeAcl, removeAclEntries, removeDefaultAcl, removeXAttr, rename, renameSnapshot, resolveLink, resolvePath, setAcl, setDefaultUri, setDefaultUri, setReplication, setStoragePolicy, setTimes, setVerifyChecksum, setWriteChecksum, setXAttr, setXAttr, startLocalOutput, supportsSymlinks, truncate, unsetStoragePolicy

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.slf4j.Logger LOG

AZURE_CHOWN_USERLIST_PROPERTY_NAME

public static final String AZURE_CHOWN_USERLIST_PROPERTY_NAME

Configuration property used to specify list of users that can perform chown operation when authorization is enabled in WASB.

See Also:

Constant Field Values

AZURE_DAEMON_USERLIST_PROPERTY_NAME

public static final String AZURE_DAEMON_USERLIST_PROPERTY_NAME

Configuration property used to specify list of daemon users that can perform chmod operation when authorization is enabled in WASB.

See Also:

Constant Field Values

AZURE_CHMOD_USERLIST_PROPERTY_NAME

public static final String AZURE_CHMOD_USERLIST_PROPERTY_NAME

Configuration property used to specify list of users that can perform chmod operation when authorization is enabled in WASB.

See Also:

Constant Field Values

SKIP_AZURE_METRICS_PROPERTY_NAME

public static final String SKIP_AZURE_METRICS_PROPERTY_NAME

See Also:

Constant Field Values

APPEND_SUPPORT_ENABLE_PROPERTY_NAME

public static final String APPEND_SUPPORT_ENABLE_PROPERTY_NAME

See Also:

Constant Field Values

AZURE_RENAME_THREADS

public static final String AZURE_RENAME_THREADS

The configuration property to set number of threads to be used for rename operation.

See Also:

Constant Field Values

DEFAULT_AZURE_RENAME_THREADS

public static final int DEFAULT_AZURE_RENAME_THREADS

The default number of threads to be used for rename operation.

See Also:

Constant Field Values

AZURE_DELETE_THREADS

public static final String AZURE_DELETE_THREADS

The configuration property to set number of threads to be used for delete operation.

See Also:

Constant Field Values

DEFAULT_AZURE_DELETE_THREADS

public static final int DEFAULT_AZURE_DELETE_THREADS

The default number of threads to be used for delete operation.

See Also:

Constant Field Values

KEY_AZURE_AUTHORIZATION

public static final String KEY_AZURE_AUTHORIZATION

Configuration key to enable authorization support in WASB.

See Also:

Constant Field Values

Constructor Detail

NativeAzureFileSystem

public NativeAzureFileSystem()

NativeAzureFileSystem

public NativeAzureFileSystem(org.apache.hadoop.fs.azure.NativeFileSystemStore store)

Method Detail

getScheme

public String getScheme()

Description copied from class: FileSystem

Return the protocol scheme for this FileSystem.

This implementation throws an UnsupportedOperationException.

Overrides:

getScheme in class FileSystem

Returns:

the protocol scheme for this FileSystem.

newMetricsSourceName

public static String newMetricsSourceName()

Creates a new metrics source name that's unique within this process.

Returns:

metric source name

checkPath

protected void checkPath(Path path)

Description copied from class: FileSystem

Check that a Path belongs to this FileSystem. The base implementation performs case insensitive equality checks of the URIs' schemes and authorities. Subclasses may implement slightly different checks.

Overrides:

checkPath in class FileSystem

Parameters:

path - to check

initialize

public void initialize(URI uri,
              Configuration conf)
                throws IOException,
                       IllegalArgumentException

Description copied from class: FileSystem

Initialize a FileSystem. Called after the new FileSystem instance is constructed, and before it is ready for use. FileSystem implementations overriding this method MUST forward it to their superclass, though the order in which it is done, and whether to alter the configuration before the invocation are options of the subclass.

Overrides:

initialize in class FileSystem

Parameters:

uri - a URI whose authority section names the host, port, etc. for this FileSystem

conf - the configuration

Throws:

IOException - on any failure to initialize this instance.

IllegalArgumentException - if the URI is considered invalid.

getHomeDirectory

public Path getHomeDirectory()

Description copied from class: FileSystem

Return the current user's home directory in this FileSystem. The default implementation returns "/user/$USER/".

Overrides:

getHomeDirectory in class FileSystem

updateWasbAuthorizer

public void updateWasbAuthorizer(org.apache.hadoop.fs.azure.WasbAuthorizerInterface authorizer)

pathToKey

public String pathToKey(Path path)

Convert the path to a key. By convention, any leading or trailing slash is removed, except for the special case of a single slash.

Parameters:

path - path converted to a key

Returns:

key string

makeAbsolute

public Path makeAbsolute(Path path)

Get the absolute version of the path (fully qualified). This is public for testing purposes.

Parameters:

path - path to be absolute path.

Returns:

fully qualified path

getStore

public org.apache.hadoop.fs.azure.AzureNativeFileSystemStore getStore()

For unit test purposes, retrieves the AzureNativeFileSystemStore store backing this file system.

Returns:

The store object.

getInstrumentation

public AzureFileSystemInstrumentation getInstrumentation()

Gets the metrics source for this file system. This is mainly here for unit testing purposes.

Returns:

the metrics source.

append

public FSDataOutputStream append(Path f,
                        int bufferSize,
                        Progressable progress)
                          throws IOException

This optional operation is not yet supported.

Specified by:

append in class FileSystem

Parameters:

f - the existing file to be appended.

bufferSize - the size of the buffer to be used.

progress - for reporting progress if it is not null.

Throws:

IOException - IO failure

create

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

Description copied from class: FileSystem

Create an FSDataOutputStream at the indicated Path with write-progress reporting.

Specified by:

create in class FileSystem

Parameters:

f - the file name to open

permission - file permission

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 - block size

progress - the progress reporter

Throws:

IOException - IO failure

See Also:

FileSystem.setPermission(Path, FsPermission)

acquireLease

public org.apache.hadoop.fs.azure.SelfRenewingLease acquireLease(Path path)
                                                          throws AzureException

Get a self-renewing lease on the specified file.

Parameters:

path - path whose lease to be renewed.

Returns:

Lease

Throws:

AzureException - when not being able to acquire a lease on the path

createNonRecursive

public FSDataOutputStream createNonRecursive(Path f,
                                    FsPermission permission,
                                    boolean overwrite,
                                    int bufferSize,
                                    short replication,
                                    long blockSize,
                                    Progressable progress)
                                      throws IOException

Description copied from class: FileSystem

Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.

Overrides:

createNonRecursive in class FileSystem

Parameters:

f - the file name to open

permission - file permission

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 - block size

progress - the progress reporter

Throws:

IOException - IO failure

See Also:

FileSystem.setPermission(Path, FsPermission)

createNonRecursive

public FSDataOutputStream createNonRecursive(Path f,
                                    FsPermission permission,
                                    EnumSet<CreateFlag> flags,
                                    int bufferSize,
                                    short replication,
                                    long blockSize,
                                    Progressable progress)
                                      throws IOException

Description copied from class: FileSystem

Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.

Overrides:

createNonRecursive in class FileSystem

Parameters:

f - the file name to open

permission - file permission

flags - CreateFlags to use for this stream.

bufferSize - the size of the buffer to be used.

replication - required block replication for the file.

blockSize - block size

progress - the progress reporter

Throws:

IOException - IO failure

See Also:

FileSystem.setPermission(Path, FsPermission)

createNonRecursive

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

Description copied from class: FileSystem

Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.

Overrides:

createNonRecursive 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 - block size

progress - the progress reporter

Throws:

IOException - IO failure

See Also:

FileSystem.setPermission(Path, FsPermission)

createInternal

protected FSDataOutputStream createInternal(Path f,
                                FsPermission permission,
                                boolean overwrite,
                                org.apache.hadoop.fs.azure.SelfRenewingLease parentFolderLease)
                                     throws FileAlreadyExistsException,
                                            IOException

This is the version of the create call that is meant for internal usage. This version is not public facing and does not perform authorization checks. It is used by the public facing create call and by FolderRenamePending to create the internal -RenamePending.json file.

Parameters:

f - the path to a file to be created.

permission - for the newly created file.

overwrite - specifies if the file should be overwritten.

parentFolderLease - lease on the parent folder.

Returns:

the output stream used to write data into the newly created file .

Throws:

IOException - if an IO error occurs while attempting to delete the path.

FileAlreadyExistsException

delete

@Deprecated
public boolean delete(Path path)
               throws IOException

Deprecated.

Description copied from class: FileSystem

Delete a file/directory.

Overrides:

delete in class FileSystem

Throws:

IOException

delete

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

Description copied from class: FileSystem

Delete a file.

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 else false.

Throws:

IOException - IO failure

delete

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

Delete the specified file or folder. The parameter skipParentFolderLastModifiedTimeUpdate is used in the case of atomic folder rename redo. In that case, there is a lease on the parent folder, so (without reworking the code) modifying the parent folder update time will fail because of a conflict with the lease. Since we are going to delete the folder soon anyway so accurate modified time is not necessary, it's easier to just skip the modified time update.

Parameters:

f - file path to be deleted.

recursive - specify deleting recursively or not.

skipParentFolderLastModifiedTimeUpdate - If true, don't update the folder last modified time.

Returns:

true if and only if the file is deleted

Throws:

IOException - Thrown when fail to delete file or directory.

getThreadPoolExecutor

public org.apache.hadoop.fs.azure.AzureFileSystemThreadPoolExecutor getThreadPoolExecutor(int threadCount,
                                                                                 String threadNamePrefix,
                                                                                 String operation,
                                                                                 String key,
                                                                                 String config)

getFileStatus

public FileStatus getFileStatus(Path f)
                         throws FileNotFoundException,
                                IOException

Description copied from class: FileSystem

Return a file status object that represents the path.

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

existsInternal

protected boolean existsInternal(Path f)
                          throws IOException

Checks if a given path exists in the filesystem. Calls getFileStatusInternal and has the same costs as the public facing exists call. This internal version of the exists call does not perform authorization checks, and is used internally by various filesystem operations that need to check if the parent/ancestor/path exist. The idea is to avoid having to configure authorization policies for these internal calls.

Parameters:

f - the path to a file or directory.

Returns:

true if path exists; otherwise false.

Throws:

IOException - if an IO error occurs while attempting to check for existence of the path.

getUri

public URI getUri()

Description copied from class: FileSystem

Returns a URI which identifies this FileSystem.

Specified by:

getUri in class FileSystem

Returns:

the URI of this filesystem.

listStatus

public FileStatus[] listStatus(Path f)
                        throws FileNotFoundException,
                               IOException

Retrieve the status of a given path if it is a file, or of all the contained files if it is a directory.

Specified by:

listStatus in class FileSystem

Parameters:

f - given path

Returns:

the statuses of the files/directories in the given patch

Throws:

FileNotFoundException - when the path does not exist

IOException - see specific implementation

mkdirs

public boolean mkdirs(Path f,
             FsPermission permission)
               throws IOException

Description copied from class: FileSystem

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

Specified by:

mkdirs in class FileSystem

Parameters:

f - path to create

permission - to apply to f

Throws:

IOException - IO failure

mkdirs

public boolean mkdirs(Path f,
             FsPermission permission,
             boolean noUmask)
               throws IOException

Throws:

IOException

open

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

Description copied from class: FileSystem

Opens an FSDataInputStream at the indicated Path.

Specified by:

open in class FileSystem

Parameters:

f - the file name to open

bufferSize - the size of the buffer to be used.

Throws:

IOException - IO failure

FileNotFoundException

rename

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

Description copied from class: FileSystem

Renames Path src to Path dst.

Specified by:

rename in class FileSystem

Parameters:

src - path to be renamed

dst - new path after rename

Returns:

true if rename is successful

Throws:

IOException - on failure

FileNotFoundException

setWorkingDirectory

public void setWorkingDirectory(Path newDir)

Set the working directory to the given directory.

Specified by:

setWorkingDirectory in class FileSystem

Parameters:

newDir - Path of new working directory

getWorkingDirectory

public Path getWorkingDirectory()

Description copied from class: FileSystem

Get the current working directory for the given FileSystem

Specified by:

getWorkingDirectory in class FileSystem

Returns:

the directory pathname

setPermission

public void setPermission(Path p,
                 FsPermission permission)
                   throws FileNotFoundException,
                          IOException

Description copied from class: FileSystem

Set permission of a path.

Overrides:

setPermission in class FileSystem

Parameters:

p - The path

permission - permission

Throws:

IOException - IO failure

FileNotFoundException

setOwner

public void setOwner(Path p,
            String username,
            String groupname)
              throws IOException

Description copied from class: FileSystem

Set owner of a path (i.e. a file or a directory). The parameters username and groupname cannot both be null.

Overrides:

setOwner in class FileSystem

Parameters:

p - The path

username - If it is null, the original username remains unchanged.

groupname - If it is null, the original groupname remains unchanged.

Throws:

IOException - IO failure

close

public void close()
           throws IOException

Description copied from class: FileSystem

Close this FileSystem instance. Will release any held locks, delete all files queued for deletion through calls to FileSystem.deleteOnExit(Path), and remove this FS instance from the cache, if cached. After this operation, the outcome of any method call on this FileSystem instance, or any input/output stream created by it is undefined.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class FileSystem

Throws:

IOException - IO failure

getDelegationToken

public Token<?> getDelegationToken(String renewer)
                            throws IOException

Get a delegation token from remote service endpoint if 'fs.azure.enable.kerberos.support' is set to 'true'.

Parameters:

renewer - the account name that is allowed to renew the token.

Returns:

delegation token

Throws:

IOException - thrown when getting the current user.

access

public void access(Path path,
          FsAction mode)
            throws IOException

Description copied from class: FileSystem

Checks if the user can access a path. The mode specifies which access checks to perform. If the requested permissions are granted, then the method returns normally. If access is denied, then the method throws an AccessControlException.

The default implementation calls FileSystem.getFileStatus(Path) and checks the returned permissions against the requested permissions. Note that the FileSystem.getFileStatus(Path) call will be subject to authorization checks. Typically, this requires search (execute) permissions on each directory in the path's prefix, but this is implementation-defined. Any file system that provides a richer authorization model (such as ACLs) may override the default implementation so that it checks against that model instead.

In general, applications should avoid using this method, due to the risk of time-of-check/time-of-use race conditions. The permissions on a file may change immediately after the access call returns. Most applications should prefer running specific file system actions as the desired user represented by a UserGroupInformation.

Parameters:

path - Path to check

mode - type of access to check

Throws:

AccessControlException - if access is denied

FileNotFoundException - if the path does not exist

IOException - see specific implementation

recoverFilesWithDanglingTempData

public void recoverFilesWithDanglingTempData(Path root,
                                    Path destination)
                                      throws IOException

Looks under the given root path for any blob that are left "dangling", meaning that they are place-holder blobs that we created while we upload the data to a temporary blob, but for some reason we crashed in the middle of the upload and left them there. If any are found, we move them to the destination given.

Parameters:

root - The root path to consider.

destination - The destination path to move any recovered files to.

Throws:

IOException - Thrown when fail to recover files.

deleteFilesWithDanglingTempData

public void deleteFilesWithDanglingTempData(Path root)
                                     throws IOException

Looks under the given root path for any blob that are left "dangling", meaning that they are place-holder blobs that we created while we upload the data to a temporary blob, but for some reason we crashed in the middle of the upload and left them there. If any are found, we delete them.

Parameters:

root - The root path to consider.

Throws:

IOException - Thrown when fail to delete.

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable

getOwnerForPath

public String getOwnerForPath(Path absolutePath)
                       throws IOException

Throws:

IOException