Using multiple databases with peewee

Question

I'm writing a "multi tenant" application. It's going to be hosted on different subdomains, and based on which subdomain it's hosted, it should use a different database.

Is it possible to define, in execution time, which database peewee should be using? If I were using django, I'd just write a router that takes care of it, but I haven't found anything similar on peewee.

Am I missing something?

Thanks!

PS: A hack like this How to query several similar databases using Peewee?, where you need to know beforehand which class to invoke wouldn't work fine in my scenario

Answer 1

You can also take a look at the ReadSlave module for an example of changing databases at run-time.

Code:

class ReadSlaveModel(Model):
    @classmethod
    def _get_read_database(cls):
        if not getattr(cls._meta, 'read_slaves', None):
            return cls._meta.database
        current_idx = getattr(cls, '_read_slave_idx', -1)
        cls._read_slave_idx = (current_idx + 1) % len(cls._meta.read_slaves)
        return cls._meta.read_slaves[cls._read_slave_idx]

    @classmethod
    def select(cls, *args, **kwargs):
        query = super(ReadSlaveModel, cls).select(*args, **kwargs)
        query.database = cls._get_read_database()
        return query

    @classmethod
    def raw(cls, *args, **kwargs):
        query = super(ReadSlaveModel, cls).raw(*args, **kwargs)
        if query._sql.lower().startswith('select'):
            query.database = cls._get_read_database()
        return query

Answer 2

Peewee provides also the possibility to use DB Proxy, where you can switch the DB easily. Peewee Documentation

database_proxy = Proxy()  # Create a proxy for our db.

class BaseModel(Model):
    class Meta:
        database = database_proxy  # Use proxy for our DB.

class User(BaseModel):
    username = CharField()

# Based on configuration, use a different database.
if app.config['DEBUG']:
    database = SqliteDatabase('local.db')
elif app.config['TESTING']:
    database = SqliteDatabase(':memory:')
else:
    database = PostgresqlDatabase('mega_production_db')

# Configure our proxy to use the db we specified in config.
database_proxy.initialize(database)