Deescovery is a Python package to find and initialize modules of your Python projects on startup.
- Find and register blueprints in a Flask project.
- Automatically initialize Flask extensions.
- Find all SQLAlchemy models to make alembic happy.
- Find all FastAPI endpoints.
- Collect all Celery tasks.
Initially designed to initialize Flask applications, it was made generic enough to work with any micro-framework or no framework at all.
Micro-framework-based projects are clean while they're small. Every micro-framework codebase I've seen, has a mess in the project initialization. With time, create_app() becomes filled with ad-hoc settings, imports-within-functions, and plug-in initializations.
The Application Factory Pattern, proposed, for example, in the official Flask documentation, and the Flask Mega-Tutorial, legitimize this approach.
The nature of create_app() leaves no place for the open-closed principle. We update this module every time we add a new plug-in, a new blueprint, or a new package.
# myproject/__init__.py
def create_app(config_class=Config):
app = Flask(__name__)
app.config.from_object(config_class)
db.init_app(app)
migrate.init_app(app, db)
login.init_app(app)
mail.init_app(app)
bootstrap.init_app(app)
moment.init_app(app)
babel.init_app(app)
from myproject.errors import bp as errors_bp
app.register_blueprint(errors_bp)
from myproject.auth import bp as auth_bp
app.register_blueprint(auth_bp, url_prefix='/auth')
return appA common Flask application. The code is based on the Flask Mega-Tutorial.
With deescovery, you can make the same code shorter, and remove the dependencies from implementation details.
# file: myproject/app.py
from flask import Flask
from deescovery import discover
from deescovery.flask import get_flask_rules
def create_app():
flask_app = Flask(__name__)
flask_app.config.from_object("myproject.config")
discover("myproject", get_flask_rules("myproject", flask_app))
return flask_app