Source code for fsspec.core

from __future__ import annotations

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

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

logger = logging.getLogger("fsspec")


[docs] class OpenFile: """ 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 be a subclass or duck-type with ``fsspec.spec.AbstractFileSystem`` 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. autoopen: bool If True, calls open() immediately. Mostly used by pickle pos: int If given and autoopen is True, seek to this location immediately """ 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 f"<OpenFile '{self.path}'>" def __enter__(self): mode = self.mode.replace("t", "").replace("b", "") + "b" try: f = self.fs.open(self.path, mode=mode) except FileNotFoundError as e: if has_magic(self.path): raise FileNotFoundError( "%s not found. The URL contains glob characters: you maybe needed\n" "to pass expand=True in fsspec.open() or the storage_options of \n" "your library. You can also set the config value 'open_expand'\n" "before import, or fsspec.core.DEFAULT_EXPAND at runtime, to True.", self.path, ) from e raise 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 = PickleableTextIOWrapper( f, encoding=self.encoding, errors=self.errors, newline=self.newline ) self.fobjects.append(f) return self.fobjects[-1] def __exit__(self, *args): self.close() @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 OpenFile object should be explicitly closed to avoid enclosed file instances persisting. You must, therefore, keep a reference to the OpenFile during the life of the file-like it generates. """ return self.__enter__()
[docs] def close(self): """Close all encapsulated file objects""" for f in reversed(self.fobjects): if "r" not in self.mode and not f.closed: f.flush() f.close() self.fobjects.clear()
[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 [s.__exit__(*args) for s in self] if "r" not in self.mode: while True: if hasattr(fs, "open_many"): # check for concurrent cache upload fs.commit_many(self.files) return if hasattr(fs, "fs") and fs.fs is not None: fs = fs.fs else: break def __getitem__(self, item): out = super().__getitem__(item) if isinstance(item, slice): return OpenFiles(out, mode=self.mode, fs=self.fs) return out def __repr__(self): return f"<List of {len(self)} OpenFile instances>"
[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 or None If given, open file using compression codec. Can either be a compression name (a key in ``fsspec.compression.compr``) or "infer" to guess the compression from the filename suffix. 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 Notes ----- For a full list of the available protocols and the implementations that they map across to see the latest online documentation: - For implementations built into ``fsspec`` see https://filesystem-spec.readthedocs.io/en/latest/api.html#built-in-implementations - For implementations in separate packages see https://filesystem-spec.readthedocs.io/en/latest/api.html#other-known-implementations """ fs, fs_token, paths = get_fs_token_paths( urlpath, mode, num=num, name_function=name_function, storage_options=kwargs, protocol=protocol, expand=expand, ) if fs.protocol == "file": fs.auto_mkdir = auto_mkdir elif "r" not in mode and auto_mkdir: parents = {fs._parent(path) for path in paths} for parent in parents: try: fs.makedirs(parent, exist_ok=True) except PermissionError: pass 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): 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] ) # [[url, protocol, kwargs], ...] out = [] previous_bit = None kwargs = kwargs.copy() for bit in reversed(bits): protocol = kwargs.pop("protocol", None) or split_protocol(bit)[0] or "file" cls = get_filesystem_class(protocol) extra_kwargs = cls._get_kwargs_from_urls(bit) kws = kwargs.pop(protocol, {}) if bit is bits[0]: kws.update(kwargs) 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.reverse() 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``. """ url = stringify_path(url) # non-FS arguments that appear in fsspec.open() # inspect could keep this in sync with open()'s signature known_kwargs = { "compression", "encoding", "errors", "expand", "mode", "name_function", "newline", "num", } kwargs = {k: v for k, v in kwargs.items() if k not in known_kwargs} chain = _un_chain(url, kwargs) 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) return fs, urlpath
DEFAULT_EXPAND = conf.get("open_expand", False)
[docs] def open( urlpath, mode="rb", compression=None, encoding="utf8", errors=None, protocol=None, newline=None, expand=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 or None If given, open file using compression codec. Can either be a compression name (a key in ``fsspec.compression.compr``) or "infer" to guess the compression from the filename suffix. 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. expand: bool or Nonw Whether to regard file paths containing special glob characters as needing expansion (finding the first match) or absolute. Setting False allows using paths which do embed such characters. If None (default), this argument takes its value from the DEFAULT_EXPAND module variable, which takes its initial value from the "open_expand" config value at startup, which will be False if not set. **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. Notes ----- For a full list of the available protocols and the implementations that they map across to see the latest online documentation: - For implementations built into ``fsspec`` see https://filesystem-spec.readthedocs.io/en/latest/api.html#built-in-implementations - For implementations in separate packages see https://filesystem-spec.readthedocs.io/en/latest/api.html#other-known-implementations """ expand = DEFAULT_EXPAND if expand is None else expand out = open_files( urlpath=[urlpath], mode=mode, compression=compression, encoding=encoding, errors=errors, protocol=protocol, newline=newline, expand=expand, **kwargs, ) if not out: raise FileNotFoundError(urlpath) return out[0]
[docs] def open_local( url: str | list[str] | Path | list[Path], mode: str = "rb", **storage_options: dict, ) -> str | list[str]: """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)) or isinstance(url, Path): 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(f"Compression type {compression} not supported") 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 if urlpath.startswith("data:"): return urlpath.split(":", 1) 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 (write mode) or any of ``*?[]`` in them (read mode). :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: # read mode if sum([1 for p in paths if "*" in p]) > 1: raise ValueError( "When writing data, only one filename mask can be specified." ) num = max(num, len(paths)) for curr_path in paths: if "*" in curr_path: # expand using name_function expanded_paths.extend(_expand_paths(curr_path, name_function, num)) else: expanded_paths.append(curr_path) # if we generated more paths that asked for, trim the list if len(expanded_paths) > num: expanded_paths = expanded_paths[:num] else: # read mode for curr_path in paths: if has_magic(curr_path): # expand using glob expanded_paths.extend(fs.glob(curr_path)) else: expanded_paths.append(curr_path) 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") urlpath0 = stringify_path(list(urlpath)[0]) else: urlpath0 = stringify_path(urlpath) storage_options = storage_options or {} if protocol: storage_options["protocol"] = protocol chain = _un_chain(urlpath0, storage_options or {}) 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(urlpath, (list, tuple, set)): pchains = [ _un_chain(stringify_path(u), storage_options or {})[0] for u in urlpath ] if len({pc[1] for pc in pchains}) > 1: raise ValueError("Protocol mismatch getting fs from %s", urlpath) paths = [pc[0] for pc in pchains] else: paths = fs._strip_protocol(paths) if isinstance(paths, (list, tuple, set)): if expand: paths = expand_paths_if_needed(paths, mode, num, fs, name_function) elif not isinstance(paths, list): paths = list(paths) else: if "w" in mode and expand: paths = _expand_paths(paths, name_function, num) elif "x" 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 class PickleableTextIOWrapper(io.TextIOWrapper): """TextIOWrapper cannot be pickled. This solves it. Requires that ``buffer`` be pickleable, which all instances of AbstractBufferedFile are. """ def __init__( self, buffer, encoding=None, errors=None, newline=None, line_buffering=False, write_through=False, ): self.args = buffer, encoding, errors, newline, line_buffering, write_through super().__init__(*self.args) def __reduce__(self): return PickleableTextIOWrapper, self.args