Handle disk space errors
Created by: malomarrec
Problem
When an executors is out of disk space, we currently try to start new jobs, which fail
It just occurred to me that the disk space issue could be handled differently by the executors, since It could be a temporary problem. Assuming the executor could detect it is out of disk space, it could skip processing new jobs until enough space is available. The other consideration I was thinking about (around Batch Changes error handling) is whether the error is meant for the end-user running Batch Changes or for a Sourcegraph admin. I imagine where we are, we cannot differentiate between the two, but as the feature evolves its probably a good idea to think about how to handle errors that can only be acted upon by admins.