Source code for apache_beam.io.localfilesystem

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"""Local File system implementation for accessing files on disk."""

from __future__ import absolute_import

import os
import shutil

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__ = ['LocalFileSystem']


[docs]class LocalFileSystem(FileSystem): """A Local ``FileSystem`` implementation for accessing files on disk. """
[docs] @classmethod def scheme(cls): """URI scheme for the FileSystem """ return None
[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 """ return os.path.join(basepath, *paths)
[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. Args: path: path as a string Returns: a pair of path components as strings. """ return os.path.split(os.path.abspath(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. """ try: os.makedirs(path) except OSError as err: raise IOError(err)
[docs] def has_dirs(self): """Whether this FileSystem supports directories.""" return True
def _url_dirname(self, url_or_path): """Pass through to os.path.dirname. This version uses os.path instead of posixpath to be compatible with the host OS. Args: url_or_path: A string in the form of /some/path. """ return os.path.dirname(url_or_path) 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. """ if not self.exists(dir_or_prefix): return try: for f in os.listdir(dir_or_prefix): f = self.join(dir_or_prefix, f) try: yield FileMetadata(f, os.path.getsize(f)) except OSError: # Files may disappear, such as when listing /tmp. pass 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) raw_file = open(path, mode) if compression_type == CompressionTypes.UNCOMPRESSED: return raw_file else: 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 """ try: if os.path.exists(destination): if os.path.isdir(destination): shutil.rmtree(destination) else: os.remove(destination) if os.path.isdir(source): shutil.copytree(source, destination) else: shutil.copy2(source, destination) except OSError as err: raise IOError(err) 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 def _rename_file(source, destination): """Rename a single file object""" try: os.rename(source, destination) except OSError as err: raise IOError(err) exceptions = {} for source, destination in zip(source_file_names, destination_file_names): try: _rename_file(source, destination) except Exception as e: # pylint: disable=broad-except exceptions[(source, destination)] = e 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 os.path.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. """ try: return os.path.getsize(path) except Exception as e: # pylint: disable=broad-except raise BeamIOError("Size 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 file size. Raises: ``BeamIOError`` if path isn't a file or doesn't exist. """ if not self.exists(path): raise BeamIOError('Path does not exist: %s' % path) return str(os.path.getsize(path))
[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 """ def _delete_path(path): """Recursively delete the file or directory at the provided path. """ try: if os.path.isdir(path): shutil.rmtree(path) else: os.remove(path) except OSError as err: raise IOError(err) 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)