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

Source code for celery.backends.mongodb

"""MongoDB result store backend."""
from datetime import datetime, timedelta

from kombu.exceptions import EncodeError
from kombu.utils.objects import cached_property
from kombu.utils.url import maybe_sanitize_url, urlparse

from celery import states
from celery.exceptions import ImproperlyConfigured

from .base import BaseBackend

try:
    import pymongo
except ImportError:
    pymongo = None

if pymongo:
    try:
        from bson.binary import Binary
    except ImportError:
        from pymongo.binary import Binary
    from pymongo.errors import InvalidDocument
else:                                       # pragma: no cover
    Binary = None

    class InvalidDocument(Exception):
        pass

__all__ = ('MongoBackend',)

BINARY_CODECS = frozenset(['pickle', 'msgpack'])


[docs]class MongoBackend(BaseBackend): """MongoDB result backend. Raises: celery.exceptions.ImproperlyConfigured: if module :pypi:`pymongo` is not available. """ mongo_host = None host = 'localhost' port = 27017 user = None password = None database_name = 'celery' taskmeta_collection = 'celery_taskmeta' groupmeta_collection = 'celery_groupmeta' max_pool_size = 10 options = None supports_autoexpire = False _connection = None def __init__(self, app=None, **kwargs): self.options = {} super().__init__(app, **kwargs) if not pymongo: raise ImproperlyConfigured( 'You need to install the pymongo library to use the ' 'MongoDB backend.') # Set option defaults for key, value in self._prepare_client_options().items(): self.options.setdefault(key, value) # update conf with mongo uri data, only if uri was given if self.url: self.url = self._ensure_mongodb_uri_compliance(self.url) uri_data = pymongo.uri_parser.parse_uri(self.url) # build the hosts list to create a mongo connection hostslist = [ f'{x[0]}:{x[1]}' for x in uri_data['nodelist'] ] self.user = uri_data['username'] self.password = uri_data['password'] self.mongo_host = hostslist if uri_data['database']: # if no database is provided in the uri, use default self.database_name = uri_data['database'] self.options.update(uri_data['options']) # update conf with specific settings config = self.app.conf.get('mongodb_backend_settings') if config is not None: if not isinstance(config, dict): raise ImproperlyConfigured( 'MongoDB backend settings should be grouped in a dict') config = dict(config) # don't modify original if 'host' in config or 'port' in config: # these should take over uri conf self.mongo_host = None self.host = config.pop('host', self.host) self.port = config.pop('port', self.port) self.mongo_host = config.pop('mongo_host', self.mongo_host) self.user = config.pop('user', self.user) self.password = config.pop('password', self.password) self.database_name = config.pop('database', self.database_name) self.taskmeta_collection = config.pop( 'taskmeta_collection', self.taskmeta_collection, ) self.groupmeta_collection = config.pop( 'groupmeta_collection', self.groupmeta_collection, ) self.options.update(config.pop('options', {})) self.options.update(config) @staticmethod def _ensure_mongodb_uri_compliance(url): parsed_url = urlparse(url) if not parsed_url.scheme.startswith('mongodb'): url = f'mongodb+{url}' if url == 'mongodb://': url += 'localhost' return url def _prepare_client_options(self): if pymongo.version_tuple >= (3,): return {'maxPoolSize': self.max_pool_size} else: # pragma: no cover return {'max_pool_size': self.max_pool_size, 'auto_start_request': False} def _get_connection(self): """Connect to the MongoDB server.""" if self._connection is None: from pymongo import MongoClient host = self.mongo_host if not host: # The first pymongo.Connection() argument (host) can be # a list of ['host:port'] elements or a mongodb connection # URI. If this is the case, don't use self.port # but let pymongo get the port(s) from the URI instead. # This enables the use of replica sets and sharding. # See pymongo.Connection() for more info. host = self.host if isinstance(host, str) \ and not host.startswith('mongodb://'): host = f'mongodb://{host}:{self.port}' # don't change self.options conf = dict(self.options) conf['host'] = host if self.user: conf['username'] = self.user if self.password: conf['password'] = self.password self._connection = MongoClient(**conf) return self._connection
[docs] def encode(self, data): if self.serializer == 'bson': # mongodb handles serialization return data payload = super().encode(data) # serializer which are in a unsupported format (pickle/binary) if self.serializer in BINARY_CODECS: payload = Binary(payload) return payload
[docs] def decode(self, data): if self.serializer == 'bson': return data return super().decode(data)
def _store_result(self, task_id, result, state, traceback=None, request=None, **kwargs): """Store return value and state of an executed task.""" meta = self._get_result_meta(result=self.encode(result), state=state, traceback=traceback, request=request) # Add the _id for mongodb meta['_id'] = task_id try: self.collection.replace_one({'_id': task_id}, meta, upsert=True) except InvalidDocument as exc: raise EncodeError(exc) return result def _get_task_meta_for(self, task_id): """Get task meta-data for a task by id.""" obj = self.collection.find_one({'_id': task_id}) if obj: return self.meta_from_decoded({ 'task_id': obj['_id'], 'status': obj['status'], 'result': self.decode(obj['result']), 'date_done': obj['date_done'], 'traceback': obj['traceback'], 'children': obj['children'], }) return {'status': states.PENDING, 'result': None} def _save_group(self, group_id, result): """Save the group result.""" meta = { '_id': group_id, 'result': self.encode([i.id for i in result]), 'date_done': datetime.utcnow(), } self.group_collection.replace_one({'_id': group_id}, meta, upsert=True) return result def _restore_group(self, group_id): """Get the result for a group by id.""" obj = self.group_collection.find_one({'_id': group_id}) if obj: return { 'task_id': obj['_id'], 'date_done': obj['date_done'], 'result': [ self.app.AsyncResult(task) for task in self.decode(obj['result']) ], } def _delete_group(self, group_id): """Delete a group by id.""" self.group_collection.delete_one({'_id': group_id}) def _forget(self, task_id): """Remove result from MongoDB. Raises: pymongo.exceptions.OperationsError: if the task_id could not be removed. """ # By using safe=True, this will wait until it receives a response from # the server. Likewise, it will raise an OperationsError if the # response was unable to be completed. self.collection.delete_one({'_id': task_id})
[docs] def cleanup(self): """Delete expired meta-data.""" if not self.expires: return self.collection.delete_many( {'date_done': {'$lt': self.app.now() - self.expires_delta}}, ) self.group_collection.delete_many( {'date_done': {'$lt': self.app.now() - self.expires_delta}}, )
def __reduce__(self, args=(), kwargs=None): kwargs = {} if not kwargs else kwargs return super().__reduce__( args, dict(kwargs, expires=self.expires, url=self.url)) def _get_database(self): conn = self._get_connection() return conn[self.database_name] @cached_property def database(self): """Get database from MongoDB connection. performs authentication if necessary. """ return self._get_database() @cached_property def collection(self): """Get the meta-data task collection.""" collection = self.database[self.taskmeta_collection] # Ensure an index on date_done is there, if not process the index # in the background. Once completed cleanup will be much faster collection.create_index('date_done', background=True) return collection @cached_property def group_collection(self): """Get the meta-data task collection.""" collection = self.database[self.groupmeta_collection] # Ensure an index on date_done is there, if not process the index # in the background. Once completed cleanup will be much faster collection.create_index('date_done', background=True) return collection @cached_property def expires_delta(self): return timedelta(seconds=self.expires)
[docs] def as_uri(self, include_password=False): """Return the backend as an URI. Arguments: include_password (bool): Password censored if disabled. """ if not self.url: return 'mongodb://' if include_password: return self.url if ',' not in self.url: return maybe_sanitize_url(self.url) uri1, remainder = self.url.split(',', 1) return ','.join([maybe_sanitize_url(uri1), remainder])