Skaffold: [Builder] Support for SBT builder

[SMR39]

Allow Skaffold to also to build with SBT https://github.com/sbt/sbt.

[priyawadhwa]

Hey @SMR39 , we're currently working on implementing a builder plugin model in skaffold, which would allow users to write plugins for whatever builder they wish to use. Once that's ready this should definitely be possible, you can track the main issue for it at #1551!

[tejal29]

@SMR39 the custom Builder plugin is now available. Can you try hooking up a custom build step which build via sbt?

Docs https://skaffold.dev/docs/how-tos/builders/#custom-build-script-run-locally

Thanks
Tejal

[bagf]

@tejal29 I've given this custom builder a try and it appears to be building and publishing the correct version tags. But the version does not get applied to my Kubernetes deployment.

As a result no k8s changes get applied after I run skaffold run -p lagom-test-service-impl

I believe sbt is using sbt-native-packager to build the docker image. This is my first attempt at using Skaffold so I might be missing something. Here's my configs and build script: https://gist.github.com/bagf/a659e5b9723b7a5743eedcdb67f31790

[priyawadhwa]

Hey @bagf -- skaffold will replace the images in your Kubernetes manifests with a new tagged image during deploy. So you'll need to do a

docker push "$IMGNAME:$IMGTAG" so that Kubernetes can pull that image later for this to work.

[bagf]

Sorry it appears I was wrong. I can confirm that the images are being pushed with the correct tag in my build script. it's working as expected after query kubectl get pod -o yaml the correct image tag is present!

[priyawadhwa]

@bagf that's great! Unless you have any more questions, can this issue be closed?

[bagf]

Yip, I'm happy 👍