Click + option groups + constraints + aliases + help themes + ...

https://cloup.readthedocs.io/

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Overview

Cloup — originally from "Click + option groups" — enriches Click with several features that make it more expressive and configurable:

• option groups
• constraints, like mutually_exclusive, that can be applied to option groups or to any group of parameters, even conditionally
• subcommand aliases
• subcommands sections, i.e. the possibility of organizing the subcommands of a Group in multiple help sections
• a themeable HelpFormatter that:
  • has more parameters for adjusting widths and spacing, which can be provided at the context and command level
  • use a different layout when the terminal width is below a certain threshold in order to improve readability
• additional parameter types, e.g. path types that use pathlib.Path instead of str by default.
• command decorators with individually typed keyword arguments, plus typed helpers such as Context.settings() and HelpFormatter.settings(), for better IDE and static type checker support.

Cloup is statically type-checked with Mypy and Pyrefly and extensively tested against multiple versions of Python with nearly 100% coverage.

Does it replace Click?

Since version 4.0.0, Cloup makes an effort to re-export the public symbols in Click's top-level namespace. Applications using Cloup can therefore access most Click functionality through cloup without maintaining separate top-level imports from both packages.

A simple example

from cloup import (
    HelpFormatter, HelpTheme, Style,
    command, option, option_group
)
from cloup.constraints import RequireAtLeast, mutually_exclusive

# Check the docs for all available arguments of HelpFormatter and HelpTheme.
formatter_settings = HelpFormatter.settings(
    theme=HelpTheme(
        invoked_command=Style(fg='bright_yellow'),
        heading=Style(fg='bright_white', bold=True),
        constraint=Style(fg='magenta'),
        col1=Style(fg='bright_yellow'),
    )
)

# In a multi-command app, you can pass formatter_settings as part
# of your context_settings so that they are propagated to subcommands.
@command(formatter_settings=formatter_settings)
@option_group(
    "Cool options",
    option('--foo', help='This text should describe the option --foo.'),
    option('--bar', help='This text should describe the option --bar.'),
    constraint=mutually_exclusive,
)
@option_group(
    "Other cool options",
    "This is the optional description of this option group.",
    option('--pippo', help='This text should describe the option --pippo.'),
    option('--pluto', help='This text should describe the option --pluto.'),
    constraint=RequireAtLeast(1),
)
def cmd(**kwargs):
    """This is the command description."""
    pass

if __name__ == '__main__':
    cmd(prog_name='invoked-command')

If you don't provide --pippo or --pluto:

Usage: invoked-command [OPTIONS]
Try 'invoked-command --help' for help.

Error: at least 1 of the following parameters must be set:
  --pippo
  --pluto

This simple example just scratches the surface. Read more in the documentation (links below).

Links

• Documentation (release | development)
• Release notes
• GitHub repository
• Q&A and discussions