auto_cli

auto_cli is a tool for calling Python functions directly from the command-line, without the need for writing argument parsers. Instead, the argument parser is automatically generated from the annotation of the function, including default arguments and types. When you use auto_cli, you can still use your Python functions from code without any changes. In fact, you can use auto_cli to generate a CLI for functions in a stand-alone script, or for an external library, as long as the functions have type annotations.

Getting Started

Add a file called auto_cli.py to any directory. This file registers all the functions that are available from the command-line. Register your command-line app with auto_cli, using

$ ac cli register_app --name my_app

Add any function you want to be able to call from the command-line to auto_cli.py. Here is a very simple auto_cli.py for an imaginary package called weather:

import auto_cli

auto_cli.register_command("weather.get_weather")

Now, you can call your function from the command-line:

$ ac my_app get_weather --location Amsterdam
21 degrees celsius. Sunny all day!

Instead of giving a string to register_command (which is convenient when the package is installed), you can also give it the function object directly. That will allow you to create a CLI for functions in arbitrary Python scripts. Then your auto_cli.py would look like this:

import auto_cli
from weather import get_weather

auto_cli.register_command(get_weather)

Alternatively, you could manipulate the PYTHONPATH environment variable to make sure Python can find your function.

Benefits

• Write your function once, call it from Python code and the command-line
• Automatically generate argument parsers, no need to duplicate argument names, default values, documentation and types.
• Automatically print the result of the function to the console, no need to clutter your code with print or log.
• Keep your production code free of decorators to describe command-line interfaces.
• Easily view all the available commands for your app.