Option to not push if a pull/rebuild hasn't changed anything and a boolean output `rebuilt`

[nitrocode]

I'd like to

• provide an option to not push if there isn't a rebuild
  • push_if_changed: true or similar ?
• know if the container had to rebuild, perhaps with an output
  • If it doesn't, then I know that there must have been file changes in the branch commits ignored successfully by the .dockerignore. If the container does not have to rebuild, then I do not have to redeploy the app.

---

We can detect if a previous build is the same as current build by comparing the Id which doesn't change if the docker build doesn't change.

docker inspect --format {{.Id}} $docker_image_name

Source: https://stackoverflow.com/a/45306984/2965993

[Aankhen]

This would be very useful for me too.

[gdvalderrama]

Instead of having a new option push_if_changed, reusing push should be posible by referencing some new variable. So instead of just push: true for example, using something like push: ${{ image_has_changed }}.

[crazy-max]

This would be part of the build reproducibility we have started to work on: https://github.com/moby/buildkit/blob/master/docs/build-repro.md.

[danieletorelli]

Hello, any update on this one?

[crazy-max]

Closing as this is not directly related to the action but BuildKit (maybe Buildx as well). See also https://github.com/moby/buildkit/blob/master/docs/build-repro.md#source_date_epoch and https://github.com/docker/build-push-action/issues/994#issuecomment-1805831110

[douglasparker]

Closing as this is not directly related to the action but BuildKit (maybe Buildx as well). See also https://github.com/moby/buildkit/blob/master/docs/build-repro.md#source_date_epoch and #994 (comment)

I’m not sure how what you linked helps us… Please reconsider this issue.