Python Fire is a Python library for automatically creating command line interfaces (CLIs) from absolutely any Python object.

Check it out at https://github.com/google/python-fire.

I originally wrote Python Fire after joining Google Brain in 2016. In March 2017 we open sourced the project, and I am proud and delighted by the growth and reception it has seen since.

To give it a try, simply pip install fire, and then call fire.Fire() as the main of any Python program.

Here’s a simple example to pique your interest, and then if you want to learn more, you should read the Python Fire Guide.

import fire

def gcd(a, b):
  """Calculates the greatest common divisor of a and b."""
  if a < b:
    a, b = b, a
  if b == 0:
    return a
  return gcd(a % b, b)


if __name__ == '__main__':
  fire.Fire(gcd)

Saving this file as gcdfire.py, we can run at the command line:

$ python gcdfire.py 45 50
5
$ python gcdfire.py 34 90
2

Just by calling Fire, we’ve turned our gcd function into a command line utility.

Fire works on functions, classes, objects, lists, etc. Any Python object at all will be turned into a sensible CLI just by calling fire.Fire on it. Learn more from the documentation here.