GerritChangeSource: orphan SSH process

[sanxiyn]

When you stop a buildmaster using GerritChangeSource? you get:

[-] Received SIGTERM, shutting down.
[-] starting 'gerrit stream-events'
[-] Main loop terminated.
[-] Server Shut Down.

That is, GerritChangeSource? restarts 'gerrit stream-events' SSH process while the buildmaster is shutting down. This results in an orphan SSH process.

[tom.prince]

This is probably best handled by using twisted.conch to connect to the server, instead of calling out to ssh as a seperate process.

[dustin]

This:

    def stopService(self):
        if self.process:
            self.process.signalProcess("KILL")

is killing the process, and then

    def streamProcessStopped(self):
        self.process = None

        # if the service is stopped, don't try to restart
        if not self.parent:
            log.msg("service is not running; not reconnecting")
            return

is re-starting it. The check for self.parent is not the same as self.running which is, sadly, an undocumented attribute of service.Service.

I think that the fix here is to add a new attribute to track whether the process should be running.

[Dustin J. Mitchell]

Track the status of the gerritChangeSource process

separately from self.parent, which does not mean 'running'

Fixes #2208.

Changeset: 097fedf23a93cb6c67395eb4b0fd5a719889a2f4