μMongo: sync/async ODM
September 23, 2025 · View on GitHub
====================== μMongo: sync/async ODM
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μMongo is a Python MongoDB ODM. Its inception comes from two needs: the lack of async ODM and the difficulty to do document (un)serialization with existing ODMs.
From this point, μMongo made a few design choices:
- Stay close to the standards MongoDB driver to keep the same API when possible:
use
find({"field": "value"})like usual but retrieve your data nicely OO wrapped ! - Work with multiple drivers (PyMongo_, TxMongo_, motor_asyncio_ and mongomock_ for the moment)
- Tight integration with Marshmallow_ serialization library to easily dump and load your data with the outside world
- i18n integration to localize validation error messages
- Free software: MIT license
- Test with 90%+ coverage ;-)
Quick example
.. code-block:: python
import datetime as dt
from pymongo import MongoClient
from umongo import Document, fields, validate
from umongo.frameworks import PyMongoInstance
db = MongoClient().test
instance = PyMongoInstance(db)
@instance.register
class User(Document):
email = fields.EmailField(required=True, unique=True)
birthday = fields.DateTimeField(
validate=validate.Range(min=dt.datetime(1900, 1, 1))
)
friends = fields.ListField(fields.ReferenceField("User"))
class Meta:
collection_name = "user"
# Make sure that unique indexes are created
User.ensure_indexes()
goku = User(email="goku@sayen.com", birthday=dt.datetime(1984, 11, 20))
goku.commit()
vegeta = User(email="vegeta@over9000.com", friends=[goku])
vegeta.commit()
vegeta.friends
# <object umongo.data_objects.List([<object umongo.dal.pymongo.PyMongoReference(document=User, pk=ObjectId('5717568613adf27be6363f78'))>])>
vegeta.dump()
# {id': '570ddb311d41c89cabceeddc', 'email': 'vegeta@over9000.com', friends': ['570ddb2a1d41c89cabceeddb']}
User.find_one({"email": "goku@sayen.com"})
# <object Document __main__.User({'id': ObjectId('570ddb2a1d41c89cabceeddb'), 'friends': <object umongo.data_objects.List([])>,
# 'email': 'goku@sayen.com', 'birthday': datetime.datetime(1984, 11, 20, 0, 0)})>
Get it now::
$ pip install umongo # This installs umongo with pymongo
$ pip install my-mongo-driver # Other MongoDB drivers must be installed manually
Or to get it along with the MongoDB driver you're planing to use::
$ pip install umongo[motor]
$ pip install umongo[txmongo]
$ pip install umongo[mongomock]
Support umongo
If you'd like to support the future of the project, please consider contributing to Marshmallow_'s Open Collective:
.. image:: https://opencollective.com/marshmallow/donate/button.png :target: https://opencollective.com/marshmallow :width: 200 :alt: Donate to our collective
.. _PyMongo: https://api.mongodb.org/python/current/ .. _TxMongo: https://txmongo.readthedocs.org/en/latest/ .. _motor_asyncio: https://motor.readthedocs.org/en/stable/ .. _mongomock: https://github.com/vmalloc/mongomock .. _Marshmallow: http://marshmallow.readthedocs.org