extencli 0.3.0

A set of utilities around click, for extensible CLI

extencli

A set of utilities around click, which offers extensible CLI mechanism, with little effort

Features

Easy third-party extensible click.group

This package offers a specialized click.group implementation. Using it, you can create a CLI that will be extended by simply installing additional modules.

As an example, here is how one would define an extensible click.group in their python package core_module:

import click

from extencli import PluginAutoloaderGroup

@click.group('core', cls=PluginAutoloaderGroup, depends_on='core_module')
def core_group():
    ...

The depends_on parameter is required:

• depends_on specifies the name of the package that CLI extensions should depend on

Now, the CLI extension package should import the core_group from the core_module like so:

from core_module.cli import core_group

@core_group.command('myext')
def cli_extension():
    ...

Now, by simply installing both the core_module and the extension third-party, the core_module will be extended with the myext command:

$> core --help
Usage: core [OPTIONS] COMMAND [ARGS]...

Options:
  --help                          Show this message and exit.

Commands:
  myext

Caveats

Silent "failure" to load extensions

If the base CLI has its extensible group declared in the __init__.py file, the internal click initialization mechanism might use different instances of the group when loaded by extensions, and when invoked through the CLI.

To avoid this, please refer to the tests's tests/python_packages/test_core python module, which is built in a way that avoid this caveat:

• extensible group should not be in the __init__.py file
• pyproject.toml may refer directly to it for script entrypoints