[Buildbot-devel] Buildbot Summit - Out of process

[Dustin J. Mitchell]

On Tue, Nov 23, 2010 at 11:25 AM, Amber Yust <ayust at yelp.com> wrote:
> One thing to keep in mind with MQ is that since it's messaging-based as
> opposed to record, then fetch, it becomes trickier to have historical data
> (especially if the status system gets restarted or redeployed elsewhere).

This has been an active area of discussion.  Two designs have been proposed:

(A) Buildmaster produces a sequence of events; those events are read
by a status-recording utility which creates a permanent historical
record

(B) Buildmaster writes status to the historical record before sending
the corresponding event.

I tend to prefer (B), mostly because (A) requires that any part of the
Buildmaster which depends on historical state must track that state on
its own.  For example, a Scheduler cannot use the database to scan for
historical changes, because it cannot guarantee that changes have been
added to the database even after those changes are delivered to the
scheduler.

Dustin