Prevent duplicate upload jobs

[bjhardcastle]

Is your feature request related to a problem? Please describe.
By accident, we managed to submit duplicate upload jobs twice this week: once through the website (not sure how this happened) and once via HTTP request (ran the same request twice).

We then weren't able to cancel the duplicate jobs - for one of them we didn't even realize until Jon alerted us.

In the end, running two uploads of the same data simultaneously didn't cause an issue: the second operation on each file must have seen that the data already existed and skipped it. A duplicate run of the sorting capsule was started after upload, and would have been wasteful had Jon not canceled it.

I can't think of a case where someone would want to upload the same session multiple times simultaneously, so I propose that the server could prevent this from happening.

Describe the solution you'd like
Before allowing a new upload job to be submitted, check there isn't already an upload job for that session in progress.

If there is a reason to allow multiple uploads with the same session ID, then compare csv/job upload parameters instead.

Describe alternatives you've considered

• user can check on site or via HTTP request.
  Problems with this are:
  • user has to be aware that duplicate upload jobs are possible
  • user has to remember to check every time, or implement their own check in code (resulting in multiple people solving the same problem)
• "submit job" helper code could be created that has this check built in; everybody uses that.
  Potential problem with this: may trade customizability of current API for usability with a subset of features, and then the full API will be used anyway when extra features are needed

[jtyoung84]

@jtyoung84 Convert to User Story