UX idea: make pueue parallel return current level of parallelism if not extra argument was given

[d33tah]

Hi! First of all, thanks for creating pueue! It's a real gem - I rarely find a tool that I pick up so quickly and immediately come up with many use cases for!

I sometimes use pueue as a tunable replacement for xargs -P. I start with a small number of parallel processes and once I get a better feel of how much resources I need, I ramp it up. Now, the question is: how much should I raise the limit by? I can't just say pueue parallel -g xargs +10 to increase it by 10 (or at least it doesn't seem to be documented), so I first need to find out what's the current level. Now, if the queue is deep, this information is "hidden" at the top of pueue status -g xargs. Beacuse of that, there's a major risk of the user missing the proverbial needle in the haystack.

My proposed solution is to change the behavior of pueue parallel -g xargs. Currently it prints an error saying it's missing a parameter:

 > pueue parallel -g xargs
error: The following required arguments were not provided:
    <PARALLEL_TASKS>

USAGE:
    pueue parallel --group <group> <PARALLEL_TASKS>

My suggestion is for it to return something like "Current parallelism for group xargs is: 20. In order to change it, run pueue parallel --group <group> <PARALLEL_TASKS>. This behavior of "get if no parameters, set if there's one" is common in other CLI tools, though nothing other than Git immediately comes to my mind.

Describe alternatives you've considered

1. pueue parallel --get-paralellism -g xargs
2. pueue parallel -g xargs +10

Actually solution no. 2 and what I proposed above aren't mutually exclusive, so it might be a good idea to implement both.

Additional context

Feature wasn't there as of 1.0.3, which I installed via cargo sometime last week.

[Nukesor]

The current amount of parallel tasks can already be seen with pueue group

We might think about moving the parallel subcommand to the group subcommand in the long run. This is probably the cleaner solution to this problem.

There was already a proposal to add subcommands to group.

• pueue group add $name
• pueue group remove $name
• pueue group parallel $name $amount

I guess this is something for a v2.0 release.

[Nukesor]

After reading through your proposal once again, does pueue group satisfy your need for an easy way of inspecting the amount of parallel tasks per group?

Moving the parallel command to the group subcommand seems somewhat unwieldy, pueue group parallel $name $amount really isn't nice to type.

[Nukesor]

Implemented in 69fdf80