[users at bb.net] Do some tasks once on the master before workers build

[Ryan Schmidt]

Hello, I'm using buildbot 0.8.12. When a change is committed to my repository, I want the buildbot master itself to do a few things (like fetching some files) before kicking off the workers to do their builds. What's the best way to do this? If I have the workers use MasterShellCommand, that runs the command on the master once for each worker, right? Which I don't want. Do I need to define a separate worker that runs on the same machine as the master, watches the repository, does the tasks, then triggers builds on the "real" workers?

Or, should I handle it outside of buildbot? Have the repository run a script when a change is committed, and that script does my extra file fetching, and then tells buildbot to do the builds? (If so, how do I tell buildbot to do that?)