Call another click command from a click command

Question

I want to use some useful functions as commands. For that I am testing the click library. I defined my three original functions then decorated as click.co

Answer 1

When you call add_name() and add_surname() directly from another function, you actually call the decorated versions of them so the arguments expected may not be as you defined them (see the answers to How to strip decorators from a function in python for some details on why).

I would suggest modifying your implementation so that you keep the original functions undecorated and create thin click-specific wrappers for them, for example:

def add_name(content, to_stdout=False):
    if not content:
        content = ''.join(sys.stdin.readlines())
    result = content + "\n\tadded name"
    if to_stdout is True:
        sys.stdout.writelines(result)
    return result

@click.command()
@click.argument('content', required=False)
@click.option('--to_stdout', default=True)
def add_name_command(content, to_stdout=False):
    return add_name(content, to_stdout)

You can then either call these functions directly or invoke them via a CLI wrapper script created by setup.py.

This might seem redundant but in fact is probably the right way to do it: one function represents your business logic, the other (the click command) is a "controller" exposing this logic via command line (there could be, for the sake of example, also a function exposing the same logic via a Web service for example).

In fact, I would even advise to put them in separate Python modules - Your "core" logic and a click-specific implementation which could be replaced for any other interface if needed.