Flask configuration

Flask-mongoengine does not provide any configuration defaults. User is responsible for setting up correct database settings, to exclude any possible misconfiguration and data corruption.

There are several options to set connection. Please note, that all except recommended are deprecated and may be removed in future versions, to lower code base complexity and bugs. If you use any deprecated connection settings approach, you should update your application configuration.

By default, flask-mongoengine2 open the connection when extension is instantiated, but you can configure it to open connection only on first database access by setting the 'connect' dictionary parameter or its MONGODB_CONNECT flat equivalent to False.

Note

Due lack of developers we are unable to answer/solve not recommended connection methods errors. Please switch to recommended method before posting any issue. Thank you.

Recommended: List of dictionaries settings

Recommended way for setting up connections is to set MONGODB_SETTINGS in you application config. MONGODB_SETTINGS is a list of dictionaries, where each dictionary is configuration for individual database (for systems with multi-database) use.

Each dictionary in MONGODB_SETTINGS will be passed to mongoengine.connect(), which will bypass settings to mongoengine.register_connection(). All settings related to mongoengine.connect() and mongoengine.register_connection() will be extracted by mentioned functions, any other keyword arguments will be silently followed to pymongo.mongo_client.MongoClient.

This allows complete and flexible database configuration.

Example:

import flask
from flask_mongoengine2 import MongoEngine

db = MongoEngine()
app = flask.Flask("example_app")
app.config["MONGODB_SETTINGS"] = [
    {
        "db": "project1",
        "host": "localhost",
        "port": 27017,
        "alias": "default",
    }
]
db.init_app(app)