dynamically change db_alias

[JDDJ]

i am using dev version of mongoengine (0.5.3), and want to know if its
possible to change a document definition db_alias dynamically.

[Ankhbayar Lhagvadorj]

Hello. 

It won't work using standard method. 

Use this method. This is little bit hard code. :(  

import mongoengine

import os

DEFAULT_DB = "default_db"

class DynamicAliasModel(mongoengine.Document):

    # .... model definition.

    @classmethod

    def _get_db(cls):

        dynamic_alias = os.environ.get("db_alias", DEFAULT_DB )

        return mongoengine.connection.get_db(dynamic_alias)

if you need to change variable os.environ["db_alias"]  you should delete cached collection instance.

from mongoengine import base

# Too Danger :( May be slow some code.

for key, doc_class in base._document_registry.items():

   doc_class._collection = None # Remove cache collection  

  

On Fri, Jan 27, 2012 at 3:22 AM, JDDJ <jaidee...@gmail.com> wrote:

i am using dev version of mongoengine (0.5.3), and want to know if its
possible to change a document definition db_alias dynamically.

--
Хүндэтгэсэн Анхбаяр

[Ross Lawley]

Hi,

I havent looked into this but do you really have to change the cached _collection to None?

Also, to help me understand this what are your use cases for changing the db?

Ross