flask migrate db not found

I’ve been getting deeper and deeper into flask recently. I really enjoy using flask-migrate to deal with my Models, and I’ve discovered I run into this following error more often then I should.

If you see something like the following, here are the steps to help debug:

(venv) ➜ flask db init
Usage: flask [OPTIONS] COMMAND [ARGS]...
Try 'flask --help' for help.

Error: No such command 'db'.

Check your virtualenv, believe it or not your (venv) might be lying to you.

(venv) ➜  which flask
/Users/jjasghar/src/local/python/flask-app/venv/bin/flask
(venv) ➜  which pip
/Users/jjasghar/src/local/python/flask-app/venv/bin/pip

If this is ok, then go on to the next check.

Verify you have flask-migrate installed:

(venv) ➜ pip freeze
Flask-Migrate==4.0.4

If you don’t you should do pip install Flask-Migrate again.

Verify that the flask cli can’t find the db subcommand.

(venv) ➜  /Users/jjasghar/src/local/python/flask-app/venv/bin/flask
Usage: flask [OPTIONS] COMMAND [ARGS]...

  A general utility script for Flask applications.

  An application to load must be given with the '--app' option, 'FLASK_APP'
  environment variable, or with a 'wsgi.py' or 'app.py' file in the current
  directory.

Options:
  -e, --env-file FILE   Load environment variables from this file. python-
                        dotenv must be installed.
  -A, --app IMPORT      The Flask application or factory function to load, in
                        the form 'module:name'. Module can be a dotted import
                        or file path. Name is not required if it is 'app',
                        'application', 'create_app', or 'make_app', and can be
                        'name(args)' to pass arguments.
  --debug / --no-debug  Set debug mode.
  --version             Show the Flask version.
  --help                Show this message and exit.

Commands:
  routes  Show the routes for the app.
  run     Run a development server.
  shell   Run a shell in the app context.

If so, start checking your code, open up your main.py or app.py

Verify you have your “migrate” wired up correct, you should have these in your code:

from flask_migrate import Migrate


db = SQLAlchemy(app)
migrate = Migrate(app, db)

If you don’t the flask db commands don’t actually now what to migrate. After this verify the db sub command is there:

(venv) ➜  /Users/jjasghar/src/local/python/flask-app/venv/bin/flask
Usage: flask [OPTIONS] COMMAND [ARGS]...

  A general utility script for Flask applications.

  An application to load must be given with the '--app' option, 'FLASK_APP'
  environment variable, or with a 'wsgi.py' or 'app.py' file in the current
  directory.

Options:
  -e, --env-file FILE   Load environment variables from this file. python-
                        dotenv must be installed.
  -A, --app IMPORT      The Flask application or factory function to load, in
                        the form 'module:name'. Module can be a dotted import
                        or file path. Name is not required if it is 'app',
                        'application', 'create_app', or 'make_app', and can be
                        'name(args)' to pass arguments.
  --debug / --no-debug  Set debug mode.
  --version             Show the Flask version.
  --help                Show this message and exit.

Commands:
  db      Perform database migrations.
  routes  Show the routes for the app.
  run     Run a development server.
  shell   Run a shell in the app context.

If all of these things are there, you should be able to run the following and get your init off the ground:

(venv) ➜  flask-sqlite-template flask db init
  Creating directory '/Users/jjasghar/src/local/python/flask-app/migrations' ...  done
  Creating directory '/Users/jjasghar/src/local/python/flask-app/migrations/versions' ...  done
  Generating /Users/jjasghar/src/local/python/flask-app/migrations/script.py.mako ...  done
  Generating /Users/jjasghar/src/local/python/flask-app/migrations/env.py ...  done
  Generating /Users/jjasghar/src/local/python/flask-app/migrations/README ...  done
  Generating /Users/jjasghar/src/local/python/flask-app/migrations/alembic.ini ...  done
  Please edit configuration/connection/logging settings in '/Users/jjasghar/src/local/python/flask-app/migrations/alembic.ini'
  before proceeding.