taskcli - a library for pragmatic CLI tools

A library for building pragmatic CLI interfaces.

Features:

• simple to use for small scripts.
• powerful enough for more complex tools (argparse-based)
• familiar argparse syntax in the arg decorator.
• automatically adds "-v|--verbose" flag to all tasks
• automatically adds "-h|--help" flag to all tasks

Heavily inspired by the excellent argh library.

Differences to argh

Registering tasks

In taskcli registering tasks takes place via the @task decorator

Parameters without default values

Given a function with a parameter without a default value:

def foobar(path)
    print(a)

In argh, such a function results in ./tool.py /tmp/somefile

in taskcli ./tools --path /tmp/somefile

Rationale:

• This makes it easier to add a default value later, without breaking existing calls
• Arguments without default value should be used rarely. It's prudent to require the user to specify them explicitly via arg decorator.

Acknowledgements

• This library builds on ideas from the argh project
• The library uses argparse behing the scenes.

FIXME

• Text in help output broken - does include task name. We should modify parser's print-usage to include task name

TODOs

• also print env vars in help
• add -v to help
• support 'help' syntax
• add auto short flags
• add "--no-*" versino of bool flags.
• add default subtask
• add @task(name)
• add @task(aliases)
• add @task(namespace)
• allow importing tasks from other modules, even with same names
  • Right now, this will likely break task_data_args[func_name][main_name]
• Consider support file with functions prefixed with "task_", and use "main" as the default task by default