Simplifying CLI application development using fire

Hi Pythonistas!

Today we will learn about a package called fire. This helps us to create CLI application with less effort. Let us dive into the code.

Installation

pip install fire

Function based app

import fire

def hello(name="Pythonista"):
  return f"Hello {name}"

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

Run without argument

python fire_intro.py

Output

Hello Pythonista

Run with argument

python fire_intro.py --name Python

Output

Hello Python

Class based App

import fire

class CLIApp:
    def add(self, first_number, second_number):
        print("first number", first_number)
        print("second number", second_number)
        result = first_number + second_number
        print(f"The result is: {result}")

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

Run without name (with position)

python fire_intro.py add 10 20

Output

first number 10

second number 20

The result is: 30

Run with name

python fire_intro.py add --second_number 10 --first_number 20

Output

first number 20

second number 10

The result is: 30

Some experiments

python fire_intro.py add 10 --second_number 30

Output

first number 10

second number 30

The result is: 40

python fire_intro.py add 10 --first_number 30

Output

first number 30

second number 10

The result is: 40

python fire_intro.py add  --first_number 30

Output

ERROR: The function received no value for the required argument: second_number
Usage: fire_intro.py add FIRST_NUMBER SECOND_NUMBER

For detailed information on this command, run:
  fire_intro.py add --help

python fire_intro.py add --help

Output

NAME
fire_intro.py add


SYNOPSIS
fire_intro.py add FIRST_NUMBER SECOND_NUMBER


POSITIONAL ARGUMENTS

FIRST_NUMBER

SECOND_NUMBER


NOTES

You can also use flags syntax for POSITIONAL ARGUMENTS

Hope you have learned something from this post. Please share your valuable suggestions and topic suggestions with afsal@parseltongue.co.in