I define my Flask application using the app factory pattern. When using Flask-Script, I can pass the factory function to the Manager
. I'd like to use Flask's built-in Click CLI instead. How do I use the factory with Click?
My current code uses Flask-Script. How do I do this with Click?
from flask import Flask
from flask_script import Manager, Shell
def create_app():
app = Flask(__name__)
...
return app
manager = Manager(create_app)
def make_shell_context():
return dict(app=app, db=db, User=User, Role=Role)
manager.add_command('shell', Shell(make_context=make_shell_context))
if __name__ == '__main__':
manager.run()
To run the app outside of the VS Code debugger, use the following steps from a terminal: Set an environment variable for FLASK_APP . On Linux and macOS, use export set FLASK_APP=webapp ; on Windows use set FLASK_APP=webapp . Navigate into the hello_app folder, then launch the program using python -m flask run .
Installing Flask installs the flask script, a Click command line interface, in your virtualenv. Executed from the terminal, this script gives access to built-in, extension, and application-defined commands. The --help option will give more information about any commands and options.
The flask
command is a Click interface created with flask.cli.FlaskGroup
. Create your own group and pass it the factory function. Use app.shell_context_processor
to add objects to the shell.
from flask import Flask
from flask.cli import FlaskGroup
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
def create_app(script_info=None):
app = Flask(__name__)
db.init_app(app)
...
@app.shell_context_processor
def shell_context():
return {'app': app, 'db': db}
return app
cli = FlaskGroup(create_app=create_app)
@cli.command
def custom_command():
pass
if __name__ == '__main__':
cli()
Run your file instead of the flask
command. You'll get the Click interface using your factory.
FLASK_DEBUG=1 python app.py run
Ideally, create an entry point and install your package in your env. Then you can call the script as a command. Create a setup.py
file with at least the following.
project/
app/
__init__.py
setup.py
from setuptools import setup, find_packages
setup(
name='my_app',
version='1.0.0',
packages=find_packages(),
entry_points={
'console_scripts': [
'app=app:cli',
],
},
)
pip install -e /path/to/project
FLASK_DEBUG=1 app run
Using your own CLI is less robust than the built-in flask
command. Because your cli
object is defined with your other code, a module-level error will cause the reloader to fail because it can no longer import the object. The flask
command is separate from your project, so it's not affected by errors in your module.
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