BuildSlave keepalive_interval arg is ignored about buildbot

[rlabrecque]

This still seems to be an issue :(

https://github.com/buildbot/buildbot/search?q=keepalive_interval

Only 3 uses of this and all are setting values, never using it.

Our worker logs look like this:

2021-02-21 22:24:15-0800 [HangCheckProtocol,client] message from master: keepalive
2021-02-21 22:24:17-0800 [-] sending app-level keepalive
2021-02-21 22:26:17-0800 [-] sending app-level keepalive
2021-02-21 22:28:17-0800 [-] sending app-level keepalive
2021-02-21 22:30:17-0800 [-] sending app-level keepalive
2021-02-21 22:32:17-0800 [-] sending app-level keepalive
2021-02-21 22:34:17-0800 [-] sending app-level keepalive
2021-02-21 22:36:17-0800 [-] sending app-level keepalive
2021-02-21 22:38:17-0800 [-] sending app-level keepalive
2021-02-21 22:40:17-0800 [-] sending app-level keepalive
2021-02-21 22:42:17-0800 [-] sending app-level keepalive
2021-02-21 22:44:17-0800 [-] sending app-level keepalive
2021-02-21 22:46:17-0800 [-] sending app-level keepalive
2021-02-21 22:48:17-0800 [-] sending app-level keepalive
2021-02-21 22:50:17-0800 [-] sending app-level keepalive
2021-02-21 22:52:17-0800 [-] sending app-level keepalive
2021-02-21 22:54:17-0800 [-] sending app-level keepalive
2021-02-21 22:56:17-0800 [-] sending app-level keepalive
2021-02-21 22:58:17-0800 [-] sending app-level keepalive
2021-02-21 23:00:17-0800 [-] sending app-level keepalive
2021-02-21 23:02:17-0800 [-] sending app-level keepalive
2021-02-21 23:04:17-0800 [-] sending app-level keepalive
2021-02-21 23:06:17-0800 [-] sending app-level keepalive
2021-02-21 23:08:17-0800 [-] sending app-level keepalive
2021-02-21 23:10:17-0800 [-] sending app-level keepalive
2021-02-21 23:12:17-0800 [-] sending app-level keepalive
2021-02-21 23:14:17-0800 [-] sending app-level keepalive
2021-02-21 23:16:17-0800 [-] sending app-level keepalive
2021-02-21 23:18:17-0800 [-] sending app-level keepalive
2021-02-21 23:20:17-0800 [-] sending app-level keepalive
2021-02-21 23:22:17-0800 [-] sending app-level keepalive
2021-02-21 23:24:14-0800 [HangCheckProtocol,client] message from master: keepalive

        workers.append(worker.Worker('worker_name', 'worker_password', keepalive_interval=60, max_builds=1))

Our temporary fix:

class FSGWorker(worker.Worker):
    @defer.inlineCallbacks
    def attached(self, conn):
        conn.keepalive_interval = 60

        conn.stopKeepaliveTimer()

        conn._keepalive_action_handler = \
            deferwaiter.RepeatedActionHandler(conn.master.reactor, conn._keepalive_waiter,
                                              conn.keepalive_interval, conn._do_keepalive)

        conn.startKeepaliveTimer()

        yield super().attached(conn)

Looks like there's 3 pieces missing:

1. AbstractWorker never saves keepalive_interval.

   buildbot/master/buildbot/worker/base.py

   Line 65 in 5727d0e

   keepalive_interval=DEFAULT_KEEPALIVE_INTERVAL,

   (This should default to None/0)
2. PB's Connection has no config override:

   buildbot/master/buildbot/worker/protocols/pb.py

   Line 131 in 5727d0e

   keepalive_interval = 3600

3. buildbot/master/buildbot/worker/protocols/pb.py

   Lines 139 to 140 in 5727d0e

   	deferwaiter.RepeatedActionHandler(master.reactor, self._keepalive_waiter,
   	self.keepalive_interval, self._do_keepalive)

   PB's Connection __init__ should be using worker.keepalive_interval if it's set.