django：如何为工厂男孩动态指定数据库

Question

I am setting up a Django application with a lot of databases, and some of them are using the same models (they are not replicas). I already configured my routers and everything is working great. The problem appears when making the tests as I want to use factory-boy .

On a different project I could setup the database inside Meta but now, I have to select on which database to create an instance dynamically (if not, I would have to create a DjangoModelFactory for each database, which wouldn't be pretty).

Is there an (easier) way to specify the database dynamically for each creation?

Answer 1

As far as I know factory_boy ( version <=2.10.0 ) doesn't provide anything like that.

Though, your problem is the perfect use case to use a context manager. It will allow you to set the database dynamically wherever you need and only under the desired scope, and also DRY!:

# factoryboy_utils.py

@classmethod
def _get_manager(cls, model_class):
    return super(cls, cls)._get_manager(model_class).using(cls.database)

class DBAwareFactory(object):
    """
    Context manager to make model factories db aware

    Usage:
        with DBAwareFactory(PersonFactory, 'db_qa') as personfactory_on_qa:
            person_on_qa = personfactory_on_qa()
            ...
    """
    def __init__(self, cls, db):
        # Take a copy of the original cls
        self.original_cls = cls
        # Patch with needed bits for dynamic db support
        setattr(cls, 'database', db)
        setattr(cls, '_get_manager', _get_manager)
        # save the patched class
        self.patched_cls = cls

    def __enter__(self):
        return self.patched_cls

    def __exit__(self, type, value, traceback):
        return self.original_cls

and then, in your tests, you can do something like:

from factoryboy_utils import DBAwareFactory

class MyTest(TestCase):

   def test_mymodel_on_db1(self):
       ...
       with DBAwareFactory(MyModelFactory, 'db1') as MyModelFactoryForDB1:
           mymodelinstance_on_db1 = MyModelFactoryForDB1()
           # whatever you need with that model instance
           ...
       # something else here

   def test_mymodel_on_db2(self):
       ...
       with DBAwareFactory(MyModelFactory, 'db2') as MyModelFactoryForDB2:
           mymodelinstance_on_db2 = MyModelFactoryForDB2()
           # whatever you need with that model instance
           ...
       # something else here