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"""GCS file system implementation for accessing files on GCS."""
from __future__ import absolute_import
from builtins import zip
from future.utils import iteritems
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
from apache_beam.io.gcp import gcsio
__all__ = ['GCSFileSystem']
[docs]class GCSFileSystem(FileSystem):
"""A GCS ``FileSystem`` implementation for accessing files on GCS.
"""
CHUNK_SIZE = gcsio.MAX_BATCH_OPERATION_SIZE # Chuck size in batch operations
GCS_PREFIX = 'gs://'
[docs] @classmethod
def scheme(cls):
"""URI scheme for the FileSystem
"""
return 'gs'
[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(GCSFileSystem.GCS_PREFIX):
raise ValueError('Basepath %r must be GCS 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.
Head will include the GCS prefix ('gs://').
Args:
path: path as a string
Returns:
a pair of path components as strings.
"""
path = path.strip()
if not path.startswith(GCSFileSystem.GCS_PREFIX):
raise ValueError('Path %r must be GCS path.' % path)
prefix_len = len(GCSFileSystem.GCS_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 in iteritems(gcsio.GcsIO().list_prefix(dir_or_prefix)):
yield FileMetadata(path, size)
except Exception as e: # pylint: disable=broad-except
raise BeamIOError("List operation failed", {dir_or_prefix: e})
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 = gcsio.GcsIO().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):
"""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):
"""Returns a read 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, '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
"""
err_msg = ("source_file_names and destination_file_names should "
"be equal in length")
assert len(source_file_names) == len(destination_file_names), err_msg
def _copy_path(source, destination):
"""Recursively copy the file tree from the source to the destination
"""
if not destination.startswith(GCSFileSystem.GCS_PREFIX):
raise ValueError('Destination %r must be GCS path.' % destination)
# Use copy_tree if the path ends with / as it is a directory
if source.endswith('/'):
gcsio.GcsIO().copytree(source, destination)
else:
gcsio.GcsIO().copy(source, destination)
exceptions = {}
for source, destination in zip(source_file_names, destination_file_names):
try:
_copy_path(source, destination)
except Exception as e: # pylint: disable=broad-except
exceptions[(source, destination)] = e
if exceptions:
raise BeamIOError("Copy operation failed", exceptions)
[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
"""
err_msg = ("source_file_names and destination_file_names should "
"be equal in length")
assert len(source_file_names) == len(destination_file_names), err_msg
gcs_batches = []
gcs_current_batch = []
for src, dest in zip(source_file_names, destination_file_names):
gcs_current_batch.append((src, dest))
if len(gcs_current_batch) == self.CHUNK_SIZE:
gcs_batches.append(gcs_current_batch)
gcs_current_batch = []
if gcs_current_batch:
gcs_batches.append(gcs_current_batch)
# Execute GCS renames if any and return exceptions.
exceptions = {}
for batch in gcs_batches:
copy_statuses = gcsio.GcsIO().copy_batch(batch)
copy_succeeded = []
for src, dest, exception in copy_statuses:
if exception:
exceptions[(src, dest)] = exception
else:
copy_succeeded.append((src, dest))
delete_batch = [src for src, dest in copy_succeeded]
delete_statuses = gcsio.GcsIO().delete_batch(delete_batch)
for i, (src, exception) in enumerate(delete_statuses):
dest = copy_succeeded[i][1]
if exception:
exceptions[(src, dest)] = exception
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
"""
return gcsio.GcsIO().exists(path)
[docs] def size(self, path):
"""Get size of path on the FileSystem.
Args:
path: string path in question.
Returns: int size of path according to the FileSystem.
Raises:
``BeamIOError`` if path doesn't exist.
"""
return gcsio.GcsIO().size(path)
[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.
"""
return gcsio.GcsIO().last_updated(path)
[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 gcsio.GcsIO().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
"""
def _delete_path(path):
"""Recursively delete the file or directory at the provided path.
"""
if path.endswith('/'):
path_to_use = path + '*'
else:
path_to_use = path
match_result = self.match([path_to_use])[0]
statuses = gcsio.GcsIO().delete_batch(
[m.path for m in match_result.metadata_list])
failures = [e for (_, e) in statuses if e is not None]
if failures:
raise failures[0]
exceptions = {}
for path in paths:
try:
_delete_path(path)
except Exception as e: # pylint: disable=broad-except
exceptions[path] = e
if exceptions:
raise BeamIOError("Delete operation failed", exceptions)