4.7 Your first CLI

Libraries

For building a cli (Command Line Interface) you can write pure Python (no external libraries) or use a library like:

• Click

• Invoke

• Tox

• Typer

• Python Fire

• Argparse

Getting started

1. Install click library.

   pip install click
   

2. Create the directory and the file structure.

   cli  # directory project
   ├── devops_cli  # directory package
   │  ├── __init__.py
   │  └── devops_cli.py  # your script
   └── setup.py
   

   Note

   The Python interpreter is informed that a directory contains code for a Python module by the __init__.py file. A file named __init__.py may be empty. You cannot import modules into your project from another location without one.

3. Write your first cli.

   import click
   import psutil
   
   @click.group()
   def cli():
       """Simple command line tool to extract system information."""
   
   @cli.command("cpu", short_help="Show CPU")
   def cpu():
       """Shows CPU Resources."""
       click.echo(psutil.cpu_times())
   
   @cli.command("disk", short_help="Show Disk")
   def disk():
       """Shows Disk Status."""
       click.echo(psutil.disk_partitions())