Using click.command to make a function as a command

Question

I am trying to make the function log into a command using the following code inside simple.py:

import click

@click.command()
@click.option('-v', '--verbose', count=True)
def log(verbose):
    click.echo(f"Verbosity: {verbose}")

When I type the following on the command terminal:log -vvv , I get an error as : Command 'log' not found, but there are 16 similar ones.

@click.command should have converted the function log into a command? But, it doesn't work here. Could someone explain,please? Thanks!

I have tried the following commands:

log -vvv
Command 'log' not found, but there are 16 similar ones.

python3 simple.py log
Usage: simple.py [OPTIONS]
Try 'simple.py --help' for help.

Error: Got unexpected extra argument (log)

Could someone please explain what does @click.command() actually do and how's it different from running simple.py. The documentation does not make it very clear to me as well. Thanks!

Answer 1

import click

@click.command()
@click.option('-v', '--verbose', count=True)
def log(verbose):
    click.echo(f"Verbosity: {verbose}")

if __name__ == '__main__':
    log()

Then calling it like

$ python simple.py    
Verbosity: 0

$ python simple.py -v
Verbosity: 1

The way you try to run it, suggest you think about command group, i.e. nesting commands

import click

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

@cli.command('log')
@click.option('-v', '--verbose', count=True)
def log(verbose):
    click.echo(f"Verbosity: {verbose}")

@cli.command('greet')
def greet():
    click.echo("Hello")

if __name__ == '__main__':
    cli()

Then

$ python simple.py greet
Hello

$ python simple.py log -v -v # or just -vv
Verbosity: 2

Next step would be setuptools integration, etc.