Psyllid should send end-of-run alert

[wcpettus]

Related to project8/dragonfly#135, psyllid should send an alert message when it finishes a timed run, that way other control software can do run cleanup.

[nsoblath]

@wcpettus is there a particular deadline for this as far as the SC are concerned?

[wcpettus]

No. The current implementation is completely functional, I think this is a generic enhancement that would be nice.

[laroque]

We've had several discussions about moving data flow to a push model. Hornet (or a dragonfly replacement) should catch alerts from psyllid to start processing files (solves the issue where file-close triggers are not cross platform). That system would then push to DIRAC (and any local analysis, etc.).

We should think through what we actually want and specify. Specifically, what should the alert look like, and should it be at the end of the run, or whenever a file is closed, or both? What information should it include? (I'd love to start getting reports of things like the trigger rate for system-health monitoring).