I'm a little apprehensive here.

You say "Switch to X" without a reason, so I'm guessing the reason is that your pushes are slow?

My development VM is already on GCP, so my pushes to gcr.io are super fast already.

I'm concerned that this will only slow down my normal hack+push dev cycle, rather than speed it up, though I imagine this would speed up development if my primary dev machine was my laptop pushing to gcr.io from an airplane.

I believe all of our Dockerfiles are designed to make iterative development pretty painless, caching things at the last step to make the final compile quick, e.g.

https://github.com/golang/build/blob/da1460b7c9c9b65383d1336593ed9ad346f6a1c5/cmd/coordinator/Dockerfile.0#L105

So if we switch to GCP container builder, I want to understand why we're doing it and what we gain, and what sort of latency guarantees they have.

Or I want to preserve the ability to do it the current way, which I find to be interactively useful. I don't want a big slow machine between writing code and prod/staging.

oh ya this was assuming we could have both manual and that

A computer does it for us already. We type make push-prod. It's not like we're assembling a tarball in a hex editor by hand. :-)

If you just want to use new toys, that's fine, as long as it's optional to start with.

lol well I'm sticking it last on my list haha

Just my thoughts. GCP container builder may be nice to have, but it does come at a cost, so it should only be optional or can be done for "official" builds if we do need such.

I think what may be nice to improve on is switching to multi-stage Dockerfile for the builds, I think that may simplify the Makefile definitions.

multi-stage Docker would be nice. If we do that, though, make sure that for anybody running too-old Docker versions, we fail nicely with a useful error message.

I'm going to close this. We now use multi-stage Dockerfiles and the Makefiles are all super simplified. Things are much cleaner than when this bug was filed.

Even though we still don't use container builder, I'm not sure there's a big advantage.