Source code for fsspec.core

from __future__ import absolute_import, division, print_function

import io
import logging
import os
import re
from glob import has_magic

# for backwards compat, we export cache things from here too
from .caching import (  # noqa: F401
    BaseCache,
    BlockCache,
    BytesCache,
    MMapCache,
    ReadAheadCache,
    caches,
)
from .compression import compr
from .registry import filesystem, get_filesystem_class
from .utils import (
    _unstrip_protocol,
    build_name_function,
    infer_compression,
    stringify_path,
    update_storage_options,
)

logger = logging.getLogger("fsspec")


[docs]class OpenFile(object): """ File-like object to be used in a context Can layer (buffered) text-mode and compression over any file-system, which are typically binary-only. These instances are safe to serialize, as the low-level file object is not created until invoked using `with`. Parameters ---------- fs: FileSystem The file system to use for opening the file. Should match the interface of ``dask.bytes.local.LocalFileSystem``. path: str Location to open mode: str like 'rb', optional Mode of the opened file compression: str or None, optional Compression to apply encoding: str or None, optional The encoding to use if opened in text mode. errors: str or None, optional How to handle encoding errors if opened in text mode. newline: None or str Passed to TextIOWrapper in text mode, how to handle line endings. """ def __init__( self, fs, path, mode="rb", compression=None, encoding=None, errors=None, newline=None, ): self.fs = fs self.path = path self.mode = mode self.compression = get_compression(path, compression) self.encoding = encoding self.errors = errors self.newline = newline self.fobjects = [] def __reduce__(self): return ( OpenFile, ( self.fs, self.path, self.mode, self.compression, self.encoding, self.errors, self.newline, ), ) def __repr__(self): return "<OpenFile '{}'>".format(self.path) def __fspath__(self): # may raise if cannot be resolved to local file return self.open().__fspath__() def __enter__(self): mode = self.mode.replace("t", "").replace("b", "") + "b" f = self.fs.open(self.path, mode=mode) self.fobjects = [f] if self.compression is not None: compress = compr[self.compression] f = compress(f, mode=mode[0]) self.fobjects.append(f) if "b" not in self.mode: # assume, for example, that 'r' is equivalent to 'rt' as in builtin f = io.TextIOWrapper( f, encoding=self.encoding, errors=self.errors, newline=self.newline ) self.fobjects.append(f) return self.fobjects[-1] def __exit__(self, *args): self.close() def __del__(self): if hasattr(self, "fobjects"): self.fobjects.clear() # may cause cleanup of objects and close files @property def full_name(self): return _unstrip_protocol(self.path, self.fs)
[docs] def open(self): """Materialise this as a real open file without context The file should be explicitly closed to avoid enclosed file instances persisting. This code-path monkey-patches the file-like objects, so they can close even if the parent OpenFile object has already been deleted; but a with-context is better style. """ out = self.__enter__() closer = out.close fobjects = self.fobjects.copy()[:-1] mode = self.mode def close(): # this func has no reference to closer() # original close bound method of the final file-like _close(fobjects, mode) # call close on other dependent file-likes out.close = close return out
[docs] def close(self): """Close all encapsulated file objects""" _close(self.fobjects, self.mode)
[docs]class OpenFiles(list): """List of OpenFile instances Can be used in a single context, which opens and closes all of the contained files. Normal list access to get the elements works as normal. A special case is made for caching filesystems - the files will be down/uploaded together at the start or end of the context, and this may happen concurrently, if the target filesystem supports it. """ def __init__(self, *args, mode="rb", fs=None): self.mode = mode self.fs = fs self.files = [] super().__init__(*args) def __enter__(self): if self.fs is None: raise ValueError("Context has already been used") fs = self.fs while True: if hasattr(fs, "open_many"): # check for concurrent cache download; or set up for upload self.files = fs.open_many(self) return self.files if hasattr(fs, "fs") and fs.fs is not None: fs = fs.fs else: break return [s.__enter__() for s in self] def __exit__(self, *args): fs = self.fs if "r" not in self.mode: while True: if hasattr(fs, "open_many"): # check for concurrent cache upload fs.commit_many(self.files) self.files.clear() return if hasattr(fs, "fs") and fs.fs is not None: fs = fs.fs else: break [s.__exit__(*args) for s in self] def __repr__(self): return "<List of %s OpenFile instances>" % len(self)
def _close(fobjects, mode): for f in reversed(fobjects): if "r" not in mode and not f.closed: f.flush() f.close() fobjects.clear()
[docs]def open_files( urlpath, mode="rb", compression=None, encoding="utf8", errors=None, name_function=None, num=1, protocol=None, newline=None, auto_mkdir=True, expand=True, **kwargs, ): """Given a path or paths, return a list of ``OpenFile`` objects. For writing, a str path must contain the "*" character, which will be filled in by increasing numbers, e.g., "part*" -> "part1", "part2" if num=2. For either reading or writing, can instead provide explicit list of paths. Parameters ---------- urlpath: string or list Absolute or relative filepath(s). Prefix with a protocol like ``s3://`` to read from alternative filesystems. To read from multiple files you can pass a globstring or a list of paths, with the caveat that they must all have the same protocol. mode: 'rb', 'wt', etc. compression: string Compression to use. See ``dask.bytes.compression.files`` for options. encoding: str For text mode only errors: None or str Passed to TextIOWrapper in text mode name_function: function or None if opening a set of files for writing, those files do not yet exist, so we need to generate their names by formatting the urlpath for each sequence number num: int [1] if writing mode, number of files we expect to create (passed to name+function) protocol: str or None If given, overrides the protocol found in the URL. newline: bytes or None Used for line terminator in text mode. If None, uses system default; if blank, uses no translation. auto_mkdir: bool (True) If in write mode, this will ensure the target directory exists before writing, by calling ``fs.mkdirs(exist_ok=True)``. expand: bool **kwargs: dict Extra options that make sense to a particular storage connection, e.g. host, port, username, password, etc. Examples -------- >>> files = open_files('2015-*-*.csv') # doctest: +SKIP >>> files = open_files( ... 's3://bucket/2015-*-*.csv.gz', compression='gzip' ... ) # doctest: +SKIP Returns ------- An ``OpenFiles`` instance, which is a list of ``OpenFile`` objects that can be used as a single context """ fs, fs_token, paths = get_fs_token_paths( urlpath, mode, num=num, name_function=name_function, storage_options=kwargs, protocol=protocol, expand=expand, ) if "r" not in mode and auto_mkdir: parents = {fs._parent(path) for path in paths} [fs.makedirs(parent, exist_ok=True) for parent in parents] return OpenFiles( [ OpenFile( fs, path, mode=mode, compression=compression, encoding=encoding, errors=errors, newline=newline, ) for path in paths ], mode=mode, fs=fs, )
def _un_chain(path, kwargs): if isinstance(path, (tuple, list)): bits = [_un_chain(p, kwargs) for p in path] out = [] for pbit in zip(*bits): paths, protocols, kwargs = zip(*pbit) if len(set(protocols)) > 1: raise ValueError("Protocol mismatch in URL chain") if len(set(paths)) == 1: paths = paths[0] else: paths = list(paths) out.append([paths, protocols[0], kwargs[0]]) return out x = re.compile(".*[^a-z]+.*") # test for non protocol-like single word bits = ( [p if "://" in p or x.match(p) else p + "://" for p in path.split("::")] if "::" in path else [path] ) if len(bits) < 2: return [] # [[url, protocol, kwargs], ...] out = [] previous_bit = None for bit in reversed(bits): protocol = split_protocol(bit)[0] or "file" cls = get_filesystem_class(protocol) extra_kwargs = cls._get_kwargs_from_urls(bit) kws = kwargs.get(protocol, {}) kw = dict(**extra_kwargs, **kws) bit = cls._strip_protocol(bit) if ( protocol in {"blockcache", "filecache", "simplecache"} and "target_protocol" not in kw ): bit = previous_bit out.append((bit, protocol, kw)) previous_bit = bit out = list(reversed(out)) return out
[docs]def url_to_fs(url, **kwargs): """ Turn fully-qualified and potentially chained URL into filesystem instance Parameters ---------- url : str The fsspec-compatible URL **kwargs: dict Extra options that make sense to a particular storage connection, e.g. host, port, username, password, etc. Returns ------- filesystem : FileSystem The new filesystem discovered from ``url`` and created with ``**kwargs``. urlpath : str The file-systems-specific URL for ``url``. """ chain = _un_chain(url, kwargs) if len(chain) > 1: inkwargs = {} # Reverse iterate the chain, creating a nested target_* structure for i, ch in enumerate(reversed(chain)): urls, protocol, kw = ch if i == len(chain) - 1: inkwargs = dict(**kw, **inkwargs) continue inkwargs["target_options"] = dict(**kw, **inkwargs) inkwargs["target_protocol"] = protocol inkwargs["fo"] = urls urlpath, protocol, _ = chain[0] fs = filesystem(protocol, **inkwargs) else: protocol = split_protocol(url)[0] cls = get_filesystem_class(protocol) options = cls._get_kwargs_from_urls(url) update_storage_options(options, kwargs) fs = cls(**options) urlpath = fs._strip_protocol(url) return fs, urlpath
[docs]def open( urlpath, mode="rb", compression=None, encoding="utf8", errors=None, protocol=None, newline=None, **kwargs, ): """Given a path or paths, return one ``OpenFile`` object. Parameters ---------- urlpath: string or list Absolute or relative filepath. Prefix with a protocol like ``s3://`` to read from alternative filesystems. Should not include glob character(s). mode: 'rb', 'wt', etc. compression: string Compression to use. See ``dask.bytes.compression.files`` for options. encoding: str For text mode only errors: None or str Passed to TextIOWrapper in text mode protocol: str or None If given, overrides the protocol found in the URL. newline: bytes or None Used for line terminator in text mode. If None, uses system default; if blank, uses no translation. **kwargs: dict Extra options that make sense to a particular storage connection, e.g. host, port, username, password, etc. Examples -------- >>> openfile = open('2015-01-01.csv') # doctest: +SKIP >>> openfile = open( ... 's3://bucket/2015-01-01.csv.gz', compression='gzip' ... ) # doctest: +SKIP >>> with openfile as f: ... df = pd.read_csv(f) # doctest: +SKIP ... Returns ------- ``OpenFile`` object. """ return open_files( urlpath=[urlpath], mode=mode, compression=compression, encoding=encoding, errors=errors, protocol=protocol, newline=newline, expand=False, **kwargs, )[0]
[docs]def open_local(url, mode="rb", **storage_options): """Open file(s) which can be resolved to local For files which either are local, or get downloaded upon open (e.g., by file caching) Parameters ---------- url: str or list(str) mode: str Must be read mode storage_options: passed on to FS for or used by open_files (e.g., compression) """ if "r" not in mode: raise ValueError("Can only ensure local files when reading") of = open_files(url, mode=mode, **storage_options) if not getattr(of[0].fs, "local_file", False): raise ValueError( "open_local can only be used on a filesystem which" " has attribute local_file=True" ) with of as files: paths = [f.name for f in files] if isinstance(url, str) and not has_magic(url): return paths[0] return paths
def get_compression(urlpath, compression): if compression == "infer": compression = infer_compression(urlpath) if compression is not None and compression not in compr: raise ValueError("Compression type %s not supported" % compression) return compression def split_protocol(urlpath): """Return protocol, path pair""" urlpath = stringify_path(urlpath) if "://" in urlpath: protocol, path = urlpath.split("://", 1) if len(protocol) > 1: # excludes Windows paths return protocol, path return None, urlpath def strip_protocol(urlpath): """Return only path part of full URL, according to appropriate backend""" protocol, _ = split_protocol(urlpath) cls = get_filesystem_class(protocol) return cls._strip_protocol(urlpath) def expand_paths_if_needed(paths, mode, num, fs, name_function): """Expand paths if they have a ``*`` in them. :param paths: list of paths mode: str Mode in which to open files. num: int If opening in writing mode, number of files we expect to create. fs: filesystem object name_function: callable If opening in writing mode, this callable is used to generate path names. Names are generated for each partition by ``urlpath.replace('*', name_function(partition_index))``. :return: list of paths """ expanded_paths = [] paths = list(paths) if "w" in mode and sum([1 for p in paths if "*" in p]) > 1: raise ValueError("When writing data, only one filename mask can be specified.") elif "w" in mode: num = max(num, len(paths)) for curr_path in paths: if "*" in curr_path: if "w" in mode: # expand using name_function expanded_paths.extend(_expand_paths(curr_path, name_function, num)) else: # expand using glob expanded_paths.extend(fs.glob(curr_path)) else: expanded_paths.append(curr_path) # if we generated more paths that asked for, trim the list if "w" in mode and len(expanded_paths) > num: expanded_paths = expanded_paths[:num] return expanded_paths
[docs]def get_fs_token_paths( urlpath, mode="rb", num=1, name_function=None, storage_options=None, protocol=None, expand=True, ): """Filesystem, deterministic token, and paths from a urlpath and options. Parameters ---------- urlpath: string or iterable Absolute or relative filepath, URL (may include protocols like ``s3://``), or globstring pointing to data. mode: str, optional Mode in which to open files. num: int, optional If opening in writing mode, number of files we expect to create. name_function: callable, optional If opening in writing mode, this callable is used to generate path names. Names are generated for each partition by ``urlpath.replace('*', name_function(partition_index))``. storage_options: dict, optional Additional keywords to pass to the filesystem class. protocol: str or None To override the protocol specifier in the URL expand: bool Expand string paths for writing, assuming the path is a directory """ if isinstance(urlpath, (list, tuple, set)): if not urlpath: raise ValueError("empty urlpath sequence") urlpath = [stringify_path(u) for u in urlpath] else: urlpath = stringify_path(urlpath) chain = _un_chain(urlpath, storage_options or {}) if len(chain) > 1: inkwargs = {} # Reverse iterate the chain, creating a nested target_* structure for i, ch in enumerate(reversed(chain)): urls, nested_protocol, kw = ch if i == len(chain) - 1: inkwargs = dict(**kw, **inkwargs) continue inkwargs["target_options"] = dict(**kw, **inkwargs) inkwargs["target_protocol"] = nested_protocol inkwargs["fo"] = urls paths, protocol, _ = chain[0] fs = filesystem(protocol, **inkwargs) if isinstance(paths, (list, tuple, set)): paths = [fs._strip_protocol(u) for u in paths] else: paths = fs._strip_protocol(paths) else: if isinstance(urlpath, (list, tuple, set)): protocols, paths = zip(*map(split_protocol, urlpath)) if protocol is None: protocol = protocols[0] if not all(p == protocol for p in protocols): raise ValueError( "When specifying a list of paths, all paths must " "share the same protocol" ) cls = get_filesystem_class(protocol) optionss = list(map(cls._get_kwargs_from_urls, urlpath)) paths = [cls._strip_protocol(u) for u in urlpath] options = optionss[0] if not all(o == options for o in optionss): raise ValueError( "When specifying a list of paths, all paths must " "share the same file-system options" ) update_storage_options(options, storage_options) fs = cls(**options) else: protocols = split_protocol(urlpath)[0] protocol = protocol or protocols cls = get_filesystem_class(protocol) options = cls._get_kwargs_from_urls(urlpath) paths = cls._strip_protocol(urlpath) update_storage_options(options, storage_options) fs = cls(**options) if isinstance(paths, (list, tuple, set)): paths = expand_paths_if_needed(paths, mode, num, fs, name_function) else: if "w" in mode and expand: paths = _expand_paths(paths, name_function, num) elif "*" in paths: paths = [f for f in sorted(fs.glob(paths)) if not fs.isdir(f)] else: paths = [paths] return fs, fs._fs_token, paths
def _expand_paths(path, name_function, num): if isinstance(path, str): if path.count("*") > 1: raise ValueError("Output path spec must contain exactly one '*'.") elif "*" not in path: path = os.path.join(path, "*.part") if name_function is None: name_function = build_name_function(num - 1) paths = [path.replace("*", name_function(i)) for i in range(num)] if paths != sorted(paths): logger.warning( "In order to preserve order between partitions" " paths created with ``name_function`` should " "sort to partition order" ) elif isinstance(path, (tuple, list)): assert len(path) == num paths = list(path) else: raise ValueError( "Path should be either\n" "1. A list of paths: ['foo.json', 'bar.json', ...]\n" "2. A directory: 'foo/\n" "3. A path with a '*' in it: 'foo.*.json'" ) return paths