Is this supported today? If so, how do I do it?

you can emit
https://cs.chromium.org/chromium/src/third_party/chromite/lib/buildbot_annotations.py?sq=package:chromium&q=SET_BUILD_+file:%5Esrc/third_party/chromite/+package:%5Echromium$&l=104&rcl=e58c0e260bf9ee2a5c3037c026b95dbb123867a2
with a metadata dict as a value

metadata will be available in ["properties"]["metadata"]

Oh, excellent! I was assuming this was a new tag for us.

Thanks.

I'll start emitting the data data this way.

Hopefully, that will be faster and easier for GE, though it'll never be backported to really old branches. Back porting to all active release branches might be feasible.

what’s the estimated size of the manifest in JSON format?

https://pantheon.corp.google.com/storage/browser/chromeos-image-archive/master-paladin/R73-11408.0.0-rc2 is an example of a CQ builder metadata.json. That's about 35k.

https://pantheon.corp.google.com/storage/browser/chromeos-image-archive/master-release/R73-11408.0.0 is an example from a release build. It's about 48k.

These are anticipated to grow a little but not by much. Maybe doubling at the high end.

Mike is working on deploying a mitigation that will increase all builder runtimes by 5-10 minutes be rerunning `git fetch --all` on all repos at the start of every build.

In the meantime, I will continue to manually fix broken bots.