Skaffold: Skaffold should push the built image with the latest tag on GoogleCloudBuild for faster cached builds

[Inkdpixels]

Expected behavior

Using skaffold with GoogleCloudBuild and a cacheFrom directive using the same image name, we expect skaffold to instruct GCB to push the built image not only with the dirty-... tag, but also with the latest tag so we can re-use the layers on consecutive builds.

Actual behavior

Skaffold instructs GoogleCloudBuild to push the built image with the dirty tag, but not with the latest one.

Information

• Skaffold version: v0.34.0
• Operating system: MacOS 10.14.5
• Contents of skaffold.yaml:

apiVersion: skaffold/v1beta13
kind: Config
build:
  artifacts:
  - image: eu.gcr.io/my-project-id/my-image
    context: .
    docker:
      dockerfile: Dockerfile
      cacheFrom:
      - eu.gcr.io/my-project-id/my-image
  googleCloudBuild:
    projectId: my-project-id

Steps to reproduce the behavior

1. Create a gcloud project
2. Adjust the values of the skaffold.yml (e.g. my-project-id and my-image)
3. Create a dockerfile with multiple layers
4. skaffold dev
5. Another skaffold dev so you can see that no layers are being re-used.

[iasinDev]

Hi, if you put

  cacheFrom:
  - eu.gcr.io/my-project-id/my-image

with latest:

  cacheFrom:
  - eu.gcr.io/my-project-id/my-image:latest

as long as you have a latest tag in the registry it would work right?

[Inkdpixels]

@iasinDev The problem is that you have to manually push to the :latest tag each time a new image was built and pushed by skaffold, this is quite tedious.

What I would suggest is that skaffold should take care of that (maybe enabled/disabled via a setting in the skaffold.yml) so each time skaffold builds and pushes a new image, it will also be pushed as the latest image, that way the developer can enjoy cached builds.

[tstromberg]

Raising the priority, both because of the reactions, and because this seems like something we should sort out sooner than later. Thank you for raising this issue!

[iasinDev]

@iasinDev The problem is that you have to manually push to the :latest tag each time a new image was built and pushed by skaffold, this is quite tedious.

What I would suggest is that skaffold should take care of that (maybe enabled/disabled via a setting in the skaffold.yml) so each time skaffold builds and pushes a new image, it will also be pushed as the latest image, that way the developer can enjoy cached builds.

Yeah, that's the thing for that reason I downgraded to use Skaffold 0.20; this version makes the double tag, it creates the tag of the new version and at the same time tag the same image also with the latest tag, I don't know how and why in the last versions it has lost this behaviour (or maybe can be set but I don't know how)

[tejal29]

v0.20.0 fixes this because, skaffold created the build step with output as artifact.ImageName
https://github.com/GoogleContainerTools/skaffold/blob/v0.20.0/pkg/skaffold/build/gcb/desc.go#L53

vs now, its tag computed for the artifact.
https://github.com/GoogleContainerTools/skaffold/blob/5a9227ce7dfd9709547d5d2c7ad9f896ee74bafc/pkg/skaffold/build/gcb/buildpacks.go#L62

The easy way would be add image name also to the same line