Run click command from a given string

Question

I have a sample python script that uses the click library:

import click

@click.group()
def cli(): 
    pass

@cli.command()
@click.argument("name", default="User")
def hello(name):
    print(f"Hello, {name}!")

if __name__ == "__main__":
    cli()

I would like to run the command from a string so it can be called dynamically via code (with a loop over lines in a text file, for example). I have one solution using the CliRunner class, but it comes with the caveat:

This only works in single-threaded systems without any concurrency as it changes the global interpreter state.

This solution looks like:

import shlex
from click.testing import CliRunner

def run_line(line):
    runner = CliRunner()
    # Split with shlex to allow "quoted values"
    # Also use ternary to prevent empty arrays
    args = shlex.split(line) if line != "" else [""]
    # Get the function from globals, default to no subcommand
    command = globals().get(args.pop(0), cli)
    result = runner.invoke(command, args)

    print(result.output)

run_line("hello World")

The above outputs Hello, World!. I could probably use locks to guard against simultaneous access on files, but that still feels hacky given the note on the CliRunner class. Any ideas?

Run click command from a given string

0 Answers