How to call a function of a file in python

Take the following use case, where I have a script that I use in my Continues Integration (CI) pipeline and I would like to call a function in that file from the command-line with parameters.

The inspect module provides several useful functions to help get information about live objects such as modules, classes, methods, functions, tracebacks, frame objects, and code objects. For example, it can help you examine the contents of a class, retrieve the source code of a method, extract and format the argument list for a function, or get all the information you need to display a detailed traceback.

In more detail, the class inspect.Signature provides the ability to capture the signature of a Callable object, meaning that it returns the parameters of the function including each parameters type.

# @file: myscript.py

import inspect
import sys

def foo(bar: str):
    print(f"foo(bar={bar}")

if __name__ == "__main__":
    # args[0]  = current file
    # args[1]  = function name
    # args[2:] = function args : (*unpacked)
    func = globals()[sys.argv[1]]
    args = list(arg for arg in sys.argv[2:] if not "=" in arg)
    kwargs = dict(arg.split("=") for arg in sys.argv[2:] if "=" in arg)
    try:
        # Binds / maps the command-line arguments to the function
        bound_arguments = inspect.signature(func).bind(*args, **kwargs)
        func(*bound_arguments.args, **bound_arguments.kwargs)
    except TypeError as e: # throws params mismatched
        raise e
    else:
        func(*args, **kwargs)

Lets break the example down. The main expects one or more command-line arguments that are used to lookup a function by name with parameters in the current python file. Using globals we can retrieve the Callable object to our function by name. Secondly, the optional remaining arguments are sliced from sys.argv and converted to a list of args and mapped to a dictionary of keyword argument conditionally if the parameter contains a = in the string. Finally, using inspect.Signature.bind the parameters are mapped to the function. The function is called if the conditions call signature are met, otherwise it throws.

# Call using positional arguments
$ python3 myscript.py foo baz
"foo(bar=baz)"

# Call using keyword arguments
$ python3 myscript.py foo bar=baz
"foo(bar=baz)"