4.14. Initialization scripts

Some applications require basic data in order to run. For example, the users application, after installation, also needs to enter the administrator account information to be able to manage other accounts and the entire system. To record this raw data, we can use initialization scripts that are executable at the command line when a project is deployed.

From the init_func parameter of any application we can assign an initialization function to it:

from backendpy.app import App
from .controllers.init import init_data

app = App(

And an init function could be like this:

from asyncio import current_task
from backendpy.db import get_db_engine, get_db_session
from backendpy.logging import logging
from ..db import queries

LOGGER = logging.getLogger(__name__)

async def init_data(config):
    # Get db session
    db_engine = get_db_engine(config['database'], echo=False)
    db_session = get_db_session(db_engine, current_task)

        # ...
        # Create admin user
        if await queries.get_users(db_session):
            LOGGER.warning('Users created already [SKIPPED]')
                user_data = {
                    'first_name': input('Enter first name:\n'),
                    'last_name': input('Enter last name:\n'),
                    'username': input('Enter admin username:\n'),
                    'password': input('Enter admin password:\n')}
            except Exception as e:
                raise Exception(f'Input error:\n{e}')

            if await queries.set_user(db_session, user_data):
                LOGGER.info('Admin user created successfully')
                raise Exception('Admin user creation error')
        await db_session.remove()
        await db_engine.dispose()

As can be seen, the init functions receive config parameter, which can be used to access project configurations such as database information and so on.

The project manager can perform the initialization by executing the following command on the command line in the project dir:

$ backendpy init_project

By executing this command, the Backendpy framework executes the initialization scripts of all applications activated in the project configuration sequentially.