Share a sub-command among multiple top level commands

Question

I have a Python project with multiple top level entry points, let's call them foo and bar. Both entry points use the same code base, and I wish to implement a foo version and bar version command using the exact same code implementing the version() command.

So, in foo.py, I'd say

import click

@click.group()
def foo():

@foo.command
@option('--long', ...)
@option('--check', ...)
def version(long, check):
    ...

Same in bar. How can I avoid duplicating the command definitions in both files?

Answer 1

Referencing this answer, you can build a click command and add it to multiple groups or commands as two separate operations.

Build a click command:

First we need to build a click command. We will use a helper function to decorate the importable command like:

import click

def importable_command(*args, **kwargs):
    def decorator(f):
        return click.decorators.command(*args, **kwargs)(f)
    return decorator


@importable_command('version')
@click.option('--long')
@click.option('--check')
def version_cmd(long, check):
    click.echo('version long: {}'.format(long))
    click.echo('version check: {}'.format(check))

Add command to group:

Then we can import the command and add it to a group with:

from where-ever-we-defined-it import version_cmd

# Add our version command to this group
a_group.add_command(version_cmd)

Test Code:

import click

def importable_command(*args, **kwargs):
    def decorator(f):
        return click.decorators.command(*args, **kwargs)(f)
    return decorator


@importable_command('version')
@click.option('--long')
@click.option('--check')
def version_cmd(long, check):
    click.echo('version long: {}'.format(long))
    click.echo('version check: {}'.format(check))


@click.group()
def cli():
    """An Awesome CLI"""


# Add our version command to this group
cli.add_command(version_cmd)

if __name__ == "__main__":
    commands = (
        'version --long a_long',
        'version --help',
        '--help',
    )

    import sys, time

    time.sleep(1)
    print('Click Version: {}'.format(click.__version__))
    print('Python Version: {}'.format(sys.version))
    for cmd in commands:
        try:
            time.sleep(0.1)
            print('-----------')
            print('> ' + cmd)
            time.sleep(0.1)
            cli(cmd.split())

        except BaseException as exc:
            if str(exc) != '0' and \
                    not isinstance(exc, (click.ClickException, SystemExit)):
                raise

Results:

Click Version: 6.7
Python Version: 3.6.3 (v3.6.3:2c5fed8, Oct  3 2017, 18:11:49) [MSC v.1900 64 bit (AMD64)]
-----------
> version --long a_long
version long: a_long
version check: None
-----------
> version --help
Usage: test.py version [OPTIONS]

Options:
  --long TEXT
  --check TEXT
  --help        Show this message and exit.
-----------
> --help
Usage: test.py [OPTIONS] COMMAND [ARGS]...

  An Awesome CLI

Options:
  --help  Show this message and exit.

Commands:
  version