MongoEngine, create and set all DB's

mongodb.py

import settings
from mongoengine import connect as mongodb_connect
from mongoengine import register_connection
from pymongo.database import Database

_database_settings = dict(
    host=settings.DATABASE_HOST,
    port=settings.DATABASE_PORT,
    username=settings.DATABASE_USER,
    password=settings.DATABASE_PASS)

dbcnx = mongodb_connect(settings.DATABASE_NAME, **_database_settings)

_db = Database(dbcnx, 'admin')
_db.authenticate(settings.DATABASE_USER, settings.DATABASE_PASS)

for a in settings.DATABASE_MULTIPLE:
    # config
    _cfg = settings.DATABASE_MULTIPLE[a]

    # create
    _db = Database(dbcnx, _cfg.get('name'))
    _db.authenticate(settings.DATABASE_USER, settings.DATABASE_PASS)
    _db.add_user(_cfg.get('username'), _cfg.get('password'))

    # register
    register_connection(**_cfg)

settings.py

#: database (default)
DATABASE_ORM  = True
DATABASE_NAME = 'admin'
DATABASE_USER = 'admin'
DATABASE_PASS = 'admin'
DATABASE_HOST = '127.0.0.1'
DATABASE_PORT = 27017
DATABASE_CONN = 100   # poll_size
DATABASE_AREQ = True  # auto_start_request
DATABASE_UGLS = False # greenlets

#: database async
DATABASE_CACH = 10

#: database (others)
DATABASE_MULTIPLE = dict(
    users=dict(
        alias='users-db',
        name='local-users',
        username='admin',
        password='admin',
        host='127.0.0.1',
        port=27017,
        max_pool_size=100,
        auto_start_request=True,
        use_greenlets=False          
    ),

    events=dict(
        alias='events-db',
        name='local-events',
        username='admin',
        password='admin',
        host='127.0.0.1',
        port=27017,
        max_pool_size=100,
        auto_start_request=True,
        use_greenlets=False
    ),
)