Flask: Default flask.cli commands are not override-able

[allanlei]

The default commands run and shell cannot be overridden.

Using a custom command called shell, I expect the custom shell to override the builtin shell

@app.cli.command('shell', short_help='My custom shell')
def shell():
    pass

But running --help still produces flask.cli.shell's help

> python -m flask
Usage: python -m flask [OPTIONS] COMMAND [ARGS]...

  This shell command acts as general utility script for Flask applications.

  It loads the application configured (either through the FLASK_APP
  environment variable) and then provides commands either provided by the
  application or Flask itself.

  The most useful commands are the "run" and "shell" command.

  Example usage:

    $ export FLASK_APP=hello
    $ export FLASK_DEBUG=1
    $ flask run

Options:
  --help  Show this message and exit.

Commands:
  run    Runs a development server.
  shell  Runs a shell in the app context.

And running gives me flask.cli.shell's shell

> python -m flask shell

Python 3.5.2 (default, Jul 17 2016, 00:00:00) 
[GCC 4.8.4] on linux
App: wallet
Instance: app/instance
>>> 

Also,

@app.cli.command('shell_plus', short_help='bar')
def shell_plus_1():
    pass

@app.cli.command('shell_plus', short_help='foo')
def shell_plus_2():
    pass

has the behaviour I expect

Usage: python -m flask [OPTIONS] COMMAND [ARGS]...

  This shell command acts as general utility script for Flask applications.

  It loads the application configured (either through the FLASK_APP
  environment variable) and then provides commands either provided by the
  application or Flask itself.

  The most useful commands are the "run" and "shell" command.

  Example usage:

    $ export FLASK_APP=hello
    $ export FLASK_DEBUG=1
    $ flask run

Options:
  --help  Show this message and exit.

Commands:
  run         Runs a development server.
  shell       Runs a shell in the app context.
  shell_plus  foo

[mrecachinas]

This appears to be the intended behavior to ensure basic script functionality in the event the application fails. See https://github.com/pallets/flask/blob/master/flask/cli.py#L329-L349.

If there is internal interest in changing that, I have a patch ready for review.

[davidism]

from flask.cli import FlaskGroup, run_command

cli = FlaskGroup(add_default_commands=False, create_app=create_app)
cli.add_command(run_command)

@cli.command('shell', short_help='Starts an interactive shell in an app context.')
def shell_command():
    ctx = current_app.make_shell_context()

    try:
        from IPython import start_ipython
        start_ipython(argv=(), user_ns=ctx)
    except ImportError:
        from code import interact
        interact(local=ctx)

Create your own FlaskGroup, omit the default commands, add the run command, add your own shell command.

@mrecachinas PRs are always welcome, for discussion even if we don't end up merging it. I'd be interested to see what you changed.

[urbainy]

How to use flask.cli to launch the program in factory environment?

I know how to use flask_script and I have found a solution by using 'click' to make my program running. But the official document propose to use flask.cli instead of flask_script extension while I think 'click' solution is a dirty solution.

As davidism propose the code:

from flask.cli import FlaskGroup, run_command

cli = FlaskGroup(add_default_commands=False, create_app=create_app)
cli.add_command(run_command)

@cli.command('shell', short_help='Starts an interactive shell in an app context.')
def shell_command():
    ctx = current_app.make_shell_context()

    try:
        from IPython import start_ipython
        start_ipython(argv=(), user_ns=ctx)
    except ImportError:
        from code import interact
        interact(local=ctx)

It seems that there is a clean method to use 'flask.cli' by instantiating the 'FlaskGroup'. But then? What code should I write in 'if __name__ == "__main__":' segment? I don't know how to run this cli, by decorator like 'click' does or something else?

[ThiefMaster]

There is absolutely no reason to override the shell command like you did - if you want ipython, simply pip install flask-shell-ipython, then the flask shell command will use ipython instead of the default python REPL.

while I think 'click' solution is a dirty solution

Would you care to elaborate? Possibly on IRC since this seem off-topic for the issue tracker.

[davidism]

As Thief said, use the extension now. But in case you still want to do it manually, it's just like all other Click applications: you call cli.main().