Allow Parallelization Core Limits

[adamzimmermann]

Steps to reproduce

When you run a command with parallelization it uses all of the CPU cores, which puts a higher than wanted load on our QA server that is already running builds for multiple environments in parallel at the Docker level (outside the scope of Robo).

Expected behavior

When you run a command with parallelization you can specify how many cores you want to use.

Actual behavior

I am unable to specify the number of cores I want to use.

System Configuration

This is all likely N/A to this issue, but I'm providing it anyways

• A multi-core machine from https://www.tugboatqa.com/.
• Using the chromatichq/php-apache:8.1 image.

Proposed Change

I assume such a change would be done in ParallelExec::run, presumably via a new property on the class with a setter method?

• Has this been discussed before? (I couldn't find anything in the issue queue).
• Would you be open to a PR that adds this functionality
• Are there any gotchas or wisdom that you could share before I try to build something?

[greg-1-anderson]

Yes, a PR would be welcome. I am not sure off the top of my head how resource limitations can be specified in ParallelExec. Adding setters to tasks is straightforward, though, so as long as you have a mechanism to enforce the limits you want, this should be straightforward to do.

[adamzimmermann]

I'll give this a shot. Not sure when, but it's on the todo list.