default (sub)command for Group

[PAStheLoD]

I've a shameless support question or request for enhancement.

We'd like to make a command the default for a group of commands, so basically Group(invoke_without_command=True), plus somehow invoking a command as if it would have been invoked via Command.main().

Currently it turns out that somewhere deep in click the args parsing results in a no such command found error if I use any (positional) arguments.

import click

@click.group(invoke_without_command=True)
@click.pass_context
def cli(ctx):
    if ctx.invoked_subcommand is None:
        click.echo('I was invoked without subcommand')
        a.main()
    else:
        click.echo('I am about to invoke %s' % ctx.invoked_subcommand)

@cli.command()
@click.option('--test')
def a(test):
    click.echo(test)

@cli.command()
def sync():
    click.echo('The subcommand')

cli()

Thanks!

[untitaker]

Replace this:

a.main()

with:

ctx.invoke(a)

[PAStheLoD]

No go :)

pas@stranger:~/tmp/t$ python i.py --test a
Error: no such option: --test

Oh, and this is python 3.5.0. (No that it likely matters, but just to be sure.)

[untitaker]

Then ctx.forward might do the job.

I'd recommend against conflating parameters and subcommands like that though.

[PAStheLoD]

Thanks, but no luck with that either.

Sure, we might have to separate this "default" behavior (a task queue runner daemon) from the "run this and this task with such and such parameters" executable.

[untitaker]

It's probably barely implementable, but I guess it's worth a discussion at least.

[sublee]

I wanted the same behavior. Here's how I implemented an implicit sub command: https://github.com/what-studio/profiling/blob/e6894bcfb975c723b00d764682a785df71c10b70/profiling/__main__.py#L87

[sublee]

https://github.com/sublee/click-default-group

I made a separate repository for default subcommand.

[llchan]

@sublee thanks for your example. I wound up using something similar but with a slightly different interface:

class DefaultGroup(click.Group):

    ignore_unknown_options = True

    def __init__(self, *args, **kwargs):
        default_command = kwargs.pop('default_command', None)
        super(DefaultGroup, self).__init__(*args, **kwargs)
        self.default_cmd_name = None
        if default_command is not None:
            self.set_default_command(default_command)

    def set_default_command(self, command):
        if isinstance(command, basestring):
            cmd_name = command
        else:
            cmd_name = command.name
            self.add_command(command)
        self.default_cmd_name = cmd_name

    def parse_args(self, ctx, args):
        if not args and self.default_cmd_name is not None:
            args.insert(0, self.default_cmd_name)
        return super(DefaultGroup, self).parse_args(ctx, args)

    def get_command(self, ctx, cmd_name):
        if cmd_name not in self.commands and self.default_cmd_name is not None:
            ctx.args0 = cmd_name
            cmd_name = self.default_cmd_name
        return super(DefaultGroup, self).get_command(ctx, cmd_name)

    def resolve_command(self, ctx, args):
        cmd_name, cmd, args = super(DefaultGroup, self).resolve_command(ctx, args)
        args0 = getattr(ctx, 'args0', None)
        if args0 is not None:
            args.insert(0, args0)
        return cmd_name, cmd, args

This has the additional benefit that I can call group.add_command(command) with a command decorated with the vanilla click.command decorator, rather than requiring that I use the special decorator.

[llchan]

To elaborate on the last point, heres two different ways to get the same thing:

@click.group(cls=DefaultGroup, default_command='a')
def cli():
    pass

@cli.command()
@click.option('--test')
def a(test):
    click.echo(test)

@cli.command()
def sync():
    click.echo('The subcommand')

cli()

@click.group(cls=DefaultGroup)
def cli():
    pass

@click.command()
@click.option('--test')
def a(test):
    click.echo(test)

@click.command()
def sync():
    click.echo('The subcommand')

cli.add_command(a)
cli.add_command(sync)
cli.set_default_command(a)
cli()

[untitaker]

Because click-default-group exists, may we close this?

BTW @sublee your project would be a good fit for https://github.com/click-contrib

[llchan]

Yeah, that's fine. My interface is different enough that it would require a breaking change for him to incorporate the changes, so it's probably not worth the effort (especially since he's already pushed it to pypi). The snippet is short so I figured I'd just comment here in case anyone else is looking for similar functionality.

If/when we add this to click-contrib we can discuss further there.

[untitaker]

Cool

[sublee]

@llchan Your approach looks better than mine. Can I borrow the approach on click-default-group?

[llchan]

Yeah, of course! Btw, you should enable issues on your repo so we can move the discussion outside of this core click repo.

[tony]

@sublee Please enable issues in your repo @ https://github.com/sublee/click-default-group

[sublee]

@tony Oh, I didn't know. I've just enabled.

[glehmann]

@sublee You should actually consider moving click-default-group to click-contrib as proposed by @untitaker. The project really looks interesting, but I only found it by chance. It would be a lot more visible in click-contrib!

[tony]

@glehmann @sublee

Agreed. Is there any other things that get shared? Pypi/readthedocs needed to be added?

[sublee]

@glehmann I just transferred click-default-group to click-contrib. Check it out!

[oberstet]

Using @click.group(cls=DefaultGroup, default='shell', default_if_no_args=True) breaks the auto-completition from https://github.com/click-contrib/click-repl

Why is it preferred versus the following anyway (which works, and does not break click-repl?

@click.group(invoke_without_command=True)
@click.option(
    '--profile',
    help='profile to use',
    default=u'default'
)
@click.pass_context
def cli(ctx, profile):
    ctx.obj = Config(_app, profile)
    if ctx.invoked_subcommand is None:
        ctx.invoke(cmd_shell)

[untitaker]

I think this discussion should be continued in a new issue on click-default-group, not in this old thread.