Automatic builder creation for new branches

[mhoermann]

In Git (and other DVCS) branches are very easy to create and are used a lot more than in the ancient VCS like CVS, SVN,... where it was a huge administrative overhead to create one.

In buildbot however you have no way to properly work with these branches without constantly changing the config file, creating exactly that administrative overhead again.

It would be great if buildbot had some kind of builder templates that would create one builder per branch as soon as that branch is encountered the first time and remove it again once that branch hasn't been updated for a configurable time.

This would allow users to see in the waterfall which branches build and if several people commit on several of those branches quickbuilders wouldn't be as slow as full builders (like they are now since they delete the build dir when they are used on another branch).

Right now this severely limits the usefulness of buildbot on a modern DVCS unless everyone creating branches is familiar with buildbot config files and willing to edit them each time they make a new branch.

[dustin]

This would, indeed, be cool.

[nhemingway]

What I do is have a loop within master.cfg that creates a builder per branch that it finds listed in an external text file. That text file is recreated each night by a cron job (essentially doing svn ls  http://...) followed by a reconfig. It seems to work OK

[dustin]

I think you know how I feel about automatic reconfigs, but that sounds like a good solution for the time being at least.

[dustin]

Why do you need a new builder for each branch?

[tom.prince]

Currently, buildbot only takes into account the current and previous build on a given builder when determining whether to report a state transition between success and failure. If you want track that state per-branch, the only way right now is to have separate builders.

[dustin]

I'd like to de-emphasize the prevalence of builders in build status. If we can answer tomprince's concern in comment 5, then it's less important to dynamically create builders.

For cases where dynamic creation *is* necessary, I think it makes most sense to stick to the idea of dynamic reconfigs. Those are much more reliable now than 4 years ago.