Code review comment for lp:~brian-murray/daisy/remove-sandbox-dir-after-retrace

This was originally done for efficiency, if memory serves. In fact, leaving off the --sandbox-dir option would give you much the same effect in a cleaner way.

Could we not instead have a process watching the disk usage on the retracer? When it gets to a charm-defined percentage limit, this process could send SIGINT to the retracer process, which could be taught to finish up the current retrace and then terminate. The watchdog process would then clean up the retracer cache dirs and restart the retracer.

Alternatively, you could have the retracer do the cleanup on behalf of the watchdog, or just flat out kill the retracer process and put our ability to deal with retracers that die mid-retrace to the test. :)

It *should* throw the work back on the queue, since we didn't ack the message in that case, but I've never thoroughly tested it.