[PYTHON] Use click to create a sub-sub command --netsted sub-sub command -

Overview

When creating a command line tool using a command line analysis tool in python, the modules used are roughly divided into the following three.

• argparse
• click
• fire

Since argparse is a standard library, it has the advantage that it can be used without thinking, and since click is not a standard module, it is easy to implement things that are difficult to implement in the standard library.

Since I have never used fire and this article is not intended to introduce command line analysis tools, I will omit further comparison and explanation here.

How to create a subcommand using click

The method of creating a subcommand using click is as follows.

• https://click.palletsprojects.com/en/7.x/quickstart/#nesting-commands

If you want to create a program that actually works, it will be as follows.

import click

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

@cli.command()
def initdb():
    click.echo('Initialized the database')

@cli.command()
def dropdb():
    click.echo('Dropped the database')

def main():
    cli()


if __name__ == "__main__":
    main()

$ python3 cli.py 
Usage: cli.py [OPTIONS] COMMAND [ARGS]...

Options:
  --help  Show this message and exit.

Commands:
  dropdb
  initdb

$ python3 cli.py dropdb
Dropped the database
$ python3 cli.py dropdb --help
Usage: cli.py dropdb [OPTIONS]

Options:
  --help  Show this message and exit.

$ python3 cli.py initdb --help
Usage: cli.py initdb [OPTIONS]

Options:
  --help  Show this message and exit.

$ python3 cli.py initdb
Initialized the database

How to make sub-sub commands

The above is how to make it when program command <options> Recently, the number of kubectl etc. that receive two subcommands such as kubectl get pods <options> is increasing. Therefore, what should I do if I make it myself?

Even if I read the click document, it says how to make subcommands, but not how to make subsubcommands. I searched around some documents and the Web and thought that the following method was beautiful, so I made it.

.
├── modules
│   ├── sub1.py
│   └── sub2.py
└── cli.py

import click
from modules import sub1
from modules import sub2

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

def main():
    cli.add_command(sub1.sub1cli)
    cli.add_command(sub2.sub2cli)
    cli()


if __name__ == "__main__":
    main()

import click

@click.group()
def sub1cli():
    pass

@sub1cli.command()
def sub1cmd1():
    click.echo('sub1cmd1')

@sub1cli.command()
def sub1cmd2():
    click.echo('sub1cmd2')

import click

@click.group()
def sub2cli():
    pass

@sub2cli.command()
def sub2cmd1():
    click.echo('sub2cmd1')

@sub2cli.command()
def sub2cmd2():
    click.echo('sub2cmd2')

In this way, you can create it by adding click.group with click's add_command.

$ python3 cli.py 
Usage: cli.py [OPTIONS] COMMAND [ARGS]...

Options:
  --help  Show this message and exit.

Commands:
  sub1cli
  sub2cli

$ python3 cli.py sub1cli
Usage: cli.py sub1cli [OPTIONS] COMMAND [ARGS]...

Options:
  --help  Show this message and exit.

Commands:
  sub1cmd1
  sub1cmd2

$ python3 cli.py sub2cli
Usage: cli.py sub2cli [OPTIONS] COMMAND [ARGS]...

Options:
  --help  Show this message and exit.

Commands:
  sub2cmd1
  sub2cmd2