Idempotent Dispatch Key for Parameterized Jobs

[alexmunda]

Firstly, I want to say that Nomad is awesome and keep up the good work 😄

Proposal

It would be nice to be able to specify an idempotency key when dispatching a parameterized job to ensure that only 1 instance of the batch job corresponding to the supplied key can be running at a time. Perhaps it could be a special meta key (shoutout to @nickethier and @tgross for the meta idempotency idea):

meta := map[string]string{
   "idempotency_key": "terraform-run-123"
}

_, _, err = client.Jobs().Dispatch("terraform", meta, bytes, nil)

Use-cases

End Goal: If a job is dispatched with a supplied idempotency key, there should only be 1 child job running at a given time that matches the key, regardless of how many times the job is dispatched for the same key during the running child job's lifetime.

An example use case is to ensure that only 1 Terraform run matching a supplied key is running at a given time.

Attempted Solutions

None yet 😄

[schmichael]

Fixed by #10806 so closing! Thanks for the issue and PR @alexmunda!

[github-actions]

I'm going to lock this issue because it has been closed for 120 days ⏳. This helps our maintainers find and focus on the active issues.
If you have found a problem that seems similar to this, please open a new issue and complete the issue template so we can capture all the details necessary to investigate further.