Using milestone within a parallel task

[Daniel Beland]

Hi,

There's a restriction currently that prevents the use of a milestone step within a parallel execution of multiple tasks and I'm trying to understand if this is something that we could remove (I would submit a PR), but I'd like to discuss it first.

I have multiple jobs with the following pattern:

1. Build and run unit tests 

2. In parallel: 

  a. Run Integration Tests

  b. Generate Documentation

  c. Run very slow unit tests (if any)

I need to limit the number of jobs running integration tests to 1 per server and I want to use the milestone step to cancel previous builds when a newer job acquires the lock.

Currently my only option is to acquire the lock and set the milestone right before the parallel task, but then I will keep the lock until all branches complete and prevent other jobs from running their integration tests.

My only other option would be to take the integration tests branch out of the parallel step and run it before or after, but then my job will take longer to build.

Ideally, I'd like to keep the same structure but only lock resources and use the milestone step within the integration tests branch.

Option A: Modify the milestone plugin to allow it within a parallel execution, (no restriction at all)?

  - I understand it becomes unpredictable if used incorrectly , but we could print a WARNING in the console and let the users make sure they use it correctly (milestone number sequence need to increase, whatever the order they are executed, etc).

Option B: Allow a single milestone step for all branches of a parallel step?

  - Then the milestone step order becomes predictable, but it could mean stopping other branches that are currently executing

Option C: We cannot modify the current behavior

  - Please let me know why this is a bad idea to allow it in a branch

Please let me know what you think.

It would really improve my build times if I can lock only the integration tests branch.

Thanks,

Daniel

[Jesse Glick]

Without spending hours on the analysis I cannot say whether is a safe and usable extension to solve your situation, or in fact a way to accomplish it with the current step. You can clone the step to a private plugin and experiment with changes. Merging significant changes is not straightforward since it means a substantial number of new behavioral tests covering all foreseeable usage patterns.