[Django]-Django specify which database to use for module

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4👍

✅

You can read on django database routers for this, some good examples can be found online as well and they should be straightforward.

—

Another solution would be to modify the Model manager.

from django.db import models


class ReplicaRoutingManager(models.Manager):
    def get_queryset(self):
        queryset = super().get_queryset(self)

        if settings.ENV == 'production':
            return queryset.using('read-replica')

        return queryset


class Customer(models.Model):

    ...
    objects = models.Manager()
    replica_objects = ReplicaRoutingManager()

with this, you can just use the normal Customer.objects.filter and the manager should do the routing.

I still suggest going with the database router solution, and creating a custom logic in the class. But if the manager works for you, its fine.

👤ibaguio

1👍

If you want All the queries in the email_lists app to query read-replica, then a router is the way to go. If you need to query different databases within the same app, then @ibaguio’s solution is the way to go. Here’s a basic router example similar to what I’m using:

project/database_routers.py

MAP = {'some_app': 'default',
       'some_other_app': 'default',
       'email_lists': 'read-replica',}

class DatabaseRouter:

    def db_for_read(self, model, **hints):
        return MAP.get(model._meta.app_label, None)

    def db_for_write(self, model, **hints):
        return MAP.get(model._meta.app_label, None)

    def allow_relation(self, object_1, object_2, **hints):
        database_object_1 = MAP.get(object_1._meta.app_label)
        database_object_2 = MAP.get(object_2._meta.app_label)
        return database_object_1 == database_object_2

    def allow_migrate(self, db, app_label, model=None, **hints):
        return MAP.get(app_label, None)

In settings.py:

DATABASE_ROUTERS = ['project.database_router.DatabaseRouter',]

It looks like you only want it in production, so I would think you could add it conditionally:

if ENV == 'production':
    DATABASE_ROUTERS = ['project.database_router.DatabaseRouter',]
👤Rob Vezina

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