How to add another database server node in Django

Question

I've a 2 databases which I've been running on a single machine. my question is how how can I add More database server along with that I wanna use django sharding so how can I shard my data from both database according to users means user 1 data from db1 and db2 on 1st server user 2's data on another

Answer 1

You need to define a router in settings:

DATABASE_ROUTERS = ['routers.routers.ModelDatabaseRouter']

in routers create file routers:

class ModelDatabaseRouter(object):
    """Allows each model to set its own destiny"""

    def db_for_read(self, model, **hints):
        # Specify target database with field in_db in model's Meta class
        if hasattr(model._meta, 'in_db'):
            return model._meta.in_db
        return None

    def db_for_write(self, model, **hints):
        # Specify target database with field in_db in model's Meta class
        if hasattr(model._meta, 'in_db'):
            return model._meta.in_db        
        return None

    def allow_syncdb(self, db, model):      
        # Specify target database with field in_db in model's Meta class
        if hasattr(model._meta, 'in_db'):
            if model._meta.in_db == db:
                return True
            else:
                return False
        else:
            # Random models that don't specify a database can only go to 'default'
            if db == 'default':
                return True
            else:
                return False

(from ) https://djangosnippets.org/snippets/2687/

Now you can define the DB in your models like this:

class YourClass(models.Model):
    name = models.CharField(primary_key=True, max_length=50)
    creation_time = models.DateTimeField()

    class Meta:
        in_db = 'api'  <-- THIS

The db must be defined in settings:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'XXXXX',
        'USER': 'XXXXX',
        'PASSWORD': 'XXXXXX',
        'HOST': '127.0.0.1',
        'PORT': '3306',
    },
    'api': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'xxxx',
        'USER': 'xxxx',
        'PASSWORD': 'xxxxxx',
        'HOST': '127.0.0.1',
        'PORT': '3306',
    }
}