Add hooks for memmon to run a command before and after restarting a process about superlance

[smcmahon]

If this was available, we could also use it with a strategy similar to that used in the Plone Ansible Toolkit's client restart mechanism. It removes a zeo client from the cluster prior to the restart, then loads selected pages via the client before restoring it to the cluster.

[hvelarde]

@djay @erral @mauritsvanrees @smcmahon what do you think?

we can work on this if somebody guide us.

[erral]

I haven't had such a usecase, but hooks that allow pluggability are good in general. 👍 on my side if that count's for something

[hvelarde]

According with Supervisor/supervisor#31 this can be achieved "executing a script that registers a signal handler for TERM, spawns a subprocess, then waits forever, and calls the save command then kills the subprocess when it gets a TERM."