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"""Azure Blob Storage Implementation for accesing files on
Azure Blob Storage.
"""
from apache_beam.io.azure import blobstorageio
from apache_beam.io.filesystem import BeamIOError
from apache_beam.io.filesystem import CompressedFile
from apache_beam.io.filesystem import CompressionTypes
from apache_beam.io.filesystem import FileMetadata
from apache_beam.io.filesystem import FileSystem
__all__ = ['BlobStorageFileSystem']
[docs]class BlobStorageFileSystem(FileSystem):
"""An Azure Blob Storage ``FileSystem`` implementation for accesing files on
Azure Blob Storage.
"""
CHUNK_SIZE = blobstorageio.MAX_BATCH_OPERATION_SIZE
AZURE_FILE_SYSTEM_PREFIX = 'azfs://'
def __init__(self, pipeline_options):
super().__init__(pipeline_options)
self._pipeline_options = pipeline_options
[docs] @classmethod
def scheme(cls):
"""URI scheme for the FileSystem
"""
return 'azfs'
[docs] def join(self, basepath, *paths):
"""Join two or more pathname components for the filesystem
Args:
basepath: string path of the first component of the path
paths: path components to be added
Returns: full path after combining all the passed components
"""
if not basepath.startswith(BlobStorageFileSystem.AZURE_FILE_SYSTEM_PREFIX):
raise ValueError(
'Basepath %r must be an Azure Blob Storage path.' % basepath)
path = basepath
for p in paths:
path = path.rstrip('/') + '/' + p.lstrip('/')
return path
[docs] def split(self, path):
"""Splits the given path into two parts.
Splits the path into a pair (head, tail) such that tail contains the last
component of the path and head contains everything up to that.
For file-systems other than the local file-system, head should include the
prefix.
Args:
path: path as a string
Returns:
a pair of path components as strings.
"""
path = path.strip()
if not path.startswith(BlobStorageFileSystem.AZURE_FILE_SYSTEM_PREFIX):
raise ValueError('Path %r must be Azure Blob Storage path.' % path)
prefix_len = len(BlobStorageFileSystem.AZURE_FILE_SYSTEM_PREFIX)
last_sep = path[prefix_len:].rfind('/')
if last_sep >= 0:
last_sep += prefix_len
if last_sep > 0:
return (path[:last_sep], path[last_sep + 1:])
elif last_sep < 0:
return (path, '')
else:
raise ValueError('Invalid path: %s' % path)
[docs] def mkdirs(self, path):
"""Recursively create directories for the provided path.
Args:
path: string path of the directory structure that should be created
Raises:
IOError: if leaf directory already exists.
"""
pass
[docs] def has_dirs(self):
"""Whether this FileSystem supports directories."""
return False
def _list(self, dir_or_prefix):
"""List files in a location.
Listing is non-recursive (for filesystems that support directories).
Args:
dir_or_prefix: (string) A directory or location prefix (for filesystems
that don't have directories).
Returns:
Generator of ``FileMetadata`` objects.
Raises:
``BeamIOError``: if listing fails, but not if no files were found.
"""
try:
for path, (size, updated) in self._blobstorageIO().list_files(
dir_or_prefix, with_metadata=True):
yield FileMetadata(path, size, updated)
except Exception as e: # pylint: disable=broad-except
raise BeamIOError("List operation failed", {dir_or_prefix: e})
def _blobstorageIO(self):
return blobstorageio.BlobStorageIO(pipeline_options=self._pipeline_options)
def _path_open(
self,
path,
mode,
mime_type='application/octet-stream',
compression_type=CompressionTypes.AUTO):
"""Helper functions to open a file in the provided mode.
"""
compression_type = FileSystem._get_compression_type(path, compression_type)
mime_type = CompressionTypes.mime_type(compression_type, mime_type)
raw_file = self._blobstorageIO().open(path, mode, mime_type=mime_type)
if compression_type == CompressionTypes.UNCOMPRESSED:
return raw_file
return CompressedFile(raw_file, compression_type=compression_type)
[docs] def create(
self,
path,
mime_type='application/octet-stream',
compression_type=CompressionTypes.AUTO):
# type: (...) -> BinaryIO # noqa: F821
"""Returns a write channel for the given file path.
Args:
path: string path of the file object to be written to the system
mime_type: MIME type to specify the type of content in the file object
compression_type: Type of compression to be used for this object
Returns: file handle with a close function for the user to use
"""
return self._path_open(path, 'wb', mime_type, compression_type)
[docs] def open(
self,
path,
mime_type='application/octet-stream',
compression_type=CompressionTypes.AUTO):
# type: (...) -> BinaryIO # noqa: F821
"""Returns a read channel for the given file path.
Args:
path: string path of the file object to be read
mime_type: MIME type to specify the type of content in the file object
compression_type: Type of compression to be used for this object
Returns: file handle with a close function for the user to use
"""
return self._path_open(path, 'rb', mime_type, compression_type)
[docs] def copy(self, source_file_names, destination_file_names):
"""Recursively copy the file tree from the source to the destination
Args:
source_file_names: list of source file objects that needs to be copied
destination_file_names: list of destination of the new object
Raises:
``BeamIOError``: if any of the copy operations fail
"""
if not len(source_file_names) == len(destination_file_names):
message = 'Unable to copy unequal number of sources and destinations.'
raise BeamIOError(message)
src_dest_pairs = list(zip(source_file_names, destination_file_names))
return self._blobstorageIO().copy_paths(src_dest_pairs)
[docs] def rename(self, source_file_names, destination_file_names):
"""Rename the files at the source list to the destination list.
Source and destination lists should be of the same size.
Args:
source_file_names: List of file paths that need to be moved
destination_file_names: List of destination_file_names for the files
Raises:
``BeamIOError``: if any of the rename operations fail
"""
if not len(source_file_names) == len(destination_file_names):
message = 'Unable to rename unequal number of sources and destinations.'
raise BeamIOError(message)
src_dest_pairs = list(zip(source_file_names, destination_file_names))
results = self._blobstorageIO().rename_files(src_dest_pairs)
# Retrieve exceptions.
exceptions = {(src, dest): error
for (src, dest, error) in results if error is not None}
if exceptions:
raise BeamIOError("Rename operation failed.", exceptions)
[docs] def exists(self, path):
"""Check if the provided path exists on the FileSystem.
Args:
path: string path that needs to be checked.
Returns: boolean flag indicating if path exists
"""
try:
return self._blobstorageIO().exists(path)
except Exception as e: # pylint: disable=broad-except
raise BeamIOError("Exists operation failed", {path: e})
[docs] def size(self, path):
"""Get size in bytes of a file on the FileSystem.
Args:
path: string filepath of file.
Returns: int size of file according to the FileSystem.
Raises:
``BeamIOError``: if path doesn't exist.
"""
try:
return self._blobstorageIO().size(path)
except Exception as e: # pylint: disable=broad-except
raise BeamIOError("Size operation failed", {path: e})
[docs] def last_updated(self, path):
"""Get UNIX Epoch time in seconds on the FileSystem.
Args:
path: string path of file.
Returns: float UNIX Epoch time
Raises:
``BeamIOError``: if path doesn't exist.
"""
try:
return self._blobstorageIO().last_updated(path)
except Exception as e: # pylint: disable=broad-except
raise BeamIOError("Last updated operation failed", {path: e})
[docs] def checksum(self, path):
"""Fetch checksum metadata of a file on the
:class:`~apache_beam.io.filesystem.FileSystem`.
Args:
path: string path of a file.
Returns: string containing checksum
Raises:
``BeamIOError``: if path isn't a file or doesn't exist.
"""
try:
return self._blobstorageIO().checksum(path)
except Exception as e: # pylint: disable=broad-except
raise BeamIOError("Checksum operation failed", {path, e})
[docs] def delete(self, paths):
"""Deletes files or directories at the provided paths.
Directories will be deleted recursively.
Args:
paths: list of paths that give the file objects to be deleted
Raises:
``BeamIOError``: if any of the delete operations fail
"""
results = self._blobstorageIO().delete_paths(paths)
# Retrieve exceptions.
exceptions = {
path: error
for (path, error) in results.items() if error is not None
}
if exceptions:
raise BeamIOError("Delete operation failed", exceptions)