Cloud-builders: Golang 1.9 support

[cove]

Any ETA as to when the golang builder updated for 1.9?

[skelterjohn]

The gcr.io/cloud-builders/go image uses whatever Go distribution is found in the public golang:alpine or golang:wheezy distributions. Currently that is 1.7.5, but that seems pretty old at this point so I'll see if we can get something more recent.

[cove]

Cool thanks, I wonder if it would make sense to pin it to a version, so it's a little clearer from the Dockerfile what version of go is being used.

[skelterjohn]

Would you ever want to use not-the-latest-version?

[cove]

In our case no, but if it's set to latest it's hard to tell what version it's at, and it's not clear what causes it to get rebuilt when a new version is out if it's not rebuilding on commit is my thought.

[iwata]

And, how about using golang:stretch?
Because golang:wheezy is not followed 1.8.x and 1.9.x on Go public registry.

[skelterjohn]

@cove Perfectly valid reason to want a pin, thank you.

@iwata We might use golang:stretch, or we might just use golang since we don't really care about the debian version for the go builder - it just needs to be a debian.

[skelterjohn]

gcr.io/cloud-builders/go:wheezy is now deprecated in favor of gcr.io/cloud-builders/go:debian, which supports go 1.9 (and whatever golang:latest supports).