Log base image@digest when building

[imjasonh]

Before:

2022/02/11 09:15:05 Using base golang:1.17 for github.com/google/ko

After:

2022/02/11 09:13:49 Using base golang:1.17 (index.docker.io/library/golang@sha256:1a35cc2c5338409227c7293add327ebe42e1ee5465049f6c57c829588e3f8a39) for github.com/google/ko

I couldn't tell where else to find the specific base image that was used before, without trying to guess using layer digests.

[imjasonh]

This could be shorter if the base image is specified by digest in .ko.yaml, I'm not sure how common that is in practice though.

edit: fixed

[mattmoor]

That's pretty long, I wonder if we should just emit the hash part, since the rest is redundant with something we're already printing on that line.

[imjasonh]

That's pretty long, I wonder if we should just emit the hash part, since the rest is redundant with something we're already printing on that line.

Yeah, good call. Now it's just:

2022/02/11 09:53:26 Using base golang:1.17@sha256:1a35cc2c5338409227c7293add327ebe42e1ee5465049f6c57c829588e3f8a39 for github.com/google/ko