Does click lib provide a way to print the builtin help message?

Question

I am using the click lib.

In my code , sometimes I want to print help msg , But the only way I know is :

python xxx --help

But I want to print the help msg in my code using a certain function , for example:

click.print_help_msg()

Is there a function like this ?

Hydroxyl

Answer 1

You can use Command's get_help method

import click

@click.command()
@click.option('--name', help='The person to greet.')
def hello(name):
    """Simple program that greets NAME."""
    click.echo('Hello %s!' % name)

def print_help_msg(command):
    with click.Context(command) as ctx:
        click.echo(command.get_help(ctx))

>> print_help_msg(hello)

Poetaster

Sadly that's not working for my case I always get AttributeError: 'name' object has no attribute 'allow_extra_args' – Senseless

if you're using nested groups and end up with "Usage: [OPTIONS] COMMAND [ARGS]..." (ie. the root name is missing), then calling with click.Context(command, info_name='mycli') as ctx: will populate the name properly. – Marylandmarylee

And if you want to print the help of a @click.group you can use your annotated group method instead of command. – Duhon

Answer 2

In click 5.x you can now use the get_current_context() method:

def print_help():
    ctx = click.get_current_context()
    click.echo(ctx.get_help())
    ctx.exit()

And if you're interested in just printing an error message and exiting, try:

def exit_with_msg():
    ctx = click.get_current_context()
    ctx.fail("Something unexpected happened")

Burnout

Now with click 7.x, ctx.exit() gives an AttributeError as exit() has been removed. Exiting is implicit with Context unless it's utilized in a callback function (e.g. printing out your cli version via MyCli.__version__). – Chavez

Answer 3

You can use click.echo something like this :

click.echo('FooBar')

echo also supports color codes and filtering based on type such as :

click.echo('FooBar', err=True)

You can refer to the documentation for more understanding.

Fossorial

I want the output of click.echo to be the same as the output of "python xxx --help" , is there any solution? – Hydroxyl

Answer 4

I modified the sample on click's documentation and came up with this, I haven't used it before though, or tested the below code.

@click.command()
@click.option('--help')
def help():
    """Simple program that greets NAME for a total of COUNT times."""
    for x in range(count):
        click.echo(get_help_message())

def get_help_message():
    return "I AM A HELP MESSAGE!"

Would something like this not work?

Arletha

I want the output of click.echo to be the same as the output of "python xxx --help" , is there any solution? – Hydroxyl