This document describes the current stable version of Celery (5.3). For development docs, go here.

Source code for celery.backends.filesystem

"""File-system result store backend."""
import locale
import os
from datetime import datetime

from kombu.utils.encoding import ensure_bytes

from celery import uuid
from celery.backends.base import KeyValueStoreBackend
from celery.exceptions import ImproperlyConfigured

default_encoding = locale.getpreferredencoding(False)

E_NO_PATH_SET = 'You need to configure a path for the file-system backend'
E_PATH_NON_CONFORMING_SCHEME = (
    'A path for the file-system backend should conform to the file URI scheme'
)
E_PATH_INVALID = """\
The configured path for the file-system backend does not
work correctly, please make sure that it exists and has
the correct permissions.\
"""


[docs]class FilesystemBackend(KeyValueStoreBackend): """File-system result backend. Arguments: url (str): URL to the directory we should use open (Callable): open function to use when opening files unlink (Callable): unlink function to use when deleting files sep (str): directory separator (to join the directory with the key) encoding (str): encoding used on the file-system """ def __init__(self, url=None, open=open, unlink=os.unlink, sep=os.sep, encoding=default_encoding, *args, **kwargs): super().__init__(*args, **kwargs) self.url = url path = self._find_path(url) # Remove forwarding "/" for Windows os if os.name == "nt" and path.startswith("/"): path = path[1:] # We need the path and separator as bytes objects self.path = path.encode(encoding) self.sep = sep.encode(encoding) self.open = open self.unlink = unlink # Lets verify that we've everything setup right self._do_directory_test(b'.fs-backend-' + uuid().encode(encoding)) def __reduce__(self, args=(), kwargs=None): kwargs = {} if not kwargs else kwargs return super().__reduce__(args, {**kwargs, 'url': self.url}) def _find_path(self, url): if not url: raise ImproperlyConfigured(E_NO_PATH_SET) if url.startswith('file://localhost/'): return url[16:] if url.startswith('file://'): return url[7:] raise ImproperlyConfigured(E_PATH_NON_CONFORMING_SCHEME) def _do_directory_test(self, key): try: self.set(key, b'test value') assert self.get(key) == b'test value' self.delete(key) except OSError: raise ImproperlyConfigured(E_PATH_INVALID) def _filename(self, key): return self.sep.join((self.path, key))
[docs] def get(self, key): try: with self.open(self._filename(key), 'rb') as infile: return infile.read() except FileNotFoundError: pass
[docs] def set(self, key, value): with self.open(self._filename(key), 'wb') as outfile: outfile.write(ensure_bytes(value))
[docs] def mget(self, keys): for key in keys: yield self.get(key)
[docs] def delete(self, key): self.unlink(self._filename(key))
[docs] def cleanup(self): """Delete expired meta-data.""" if not self.expires: return epoch = datetime(1970, 1, 1, tzinfo=self.app.timezone) now_ts = (self.app.now() - epoch).total_seconds() cutoff_ts = now_ts - self.expires for filename in os.listdir(self.path): for prefix in (self.task_keyprefix, self.group_keyprefix, self.chord_keyprefix): if filename.startswith(prefix): path = os.path.join(self.path, filename) if os.stat(path).st_mtime < cutoff_ts: self.unlink(path) break