Allow docker image creation timestamp to be configurable

[philipp-paland]

As mentioned in #20126 (comment) I'm creating an enhancement request.

For good reasons (reproducibility AFAIK) the docker image created by e.g. the maven plugins have their creation timestamp set to a fixed point in time (1970-01-01?). Other tools that use the same approach have a way to customize this, e.g with jib you can set creationTime to USE_CURRENT_TIMESTAMP. I would like to have this feature also in Spring Boot. I do not know if the build packs already support this - then it might just be a question of surfacing that through the maven plugin - or if the feature would also need to be implemented there.

My use-case is that our docker registry (Gitlab) has an expiration policy feature that uses the timestamp to delete old images. That feature is currently not usable for us.

[scottfrederick]

There is a Cloud Native Buildpacks RFC that proposed lifecycle support for customization of the dates in image metadata in a way that could be used by any platform (like pack CLI and Spring Boot build plugins), but the RFC was closed without action.

Without support for setting a current timestamp in the CNB lifecycle, the Spring Boot plugins should be able to set the createDate of the resulting image but may not have control over timestamps of all the layers in the image. I don't know how much this matter to users who don't care about build reproducibility and are willing to give that up in order to get a current createDate on the image.

[scottfrederick]

In addition to allowing configuration for using the current date/time, this enhancement could allow the user to provide their own fixed date/time as an alternative to the default epoch createDate (1980-01-01T00:00:01Z). Marking this as pending-design-work so we can discuss further before implementation.

[vgropp]

to specify an alternative would be very useful as we could use the git timestamp for a somewhat reproducible build.

As far as i can tell, pack does already supports this feature: --creation-time string Desired create time in the output image config. Accepted values are Unix timestamps (e.g., '1641013200'), or 'now'. Platform API version must be at least 0.9 to use this feature.

[quaff]

to specify an alternative would be very useful as we could use the git timestamp for a somewhat reproducible build.

As far as i can tell, pack does already supports this feature: --creation-time string Desired create time in the output image config. Accepted values are Unix timestamps (e.g., '1641013200'), or 'now'. Platform API version must be at least 0.9 to use this feature.

@scottfrederick Would spring boot follow up?

[plebcity]

This issue is more important now since many will be using bootBuildImage to build native images using the buildpacks.

[scottfrederick]

@quaff @plebcity This issue is still open, and marked as an enhancement for a future release. It just hasn't been a high priority compared to other things we've been working on. We can take a look at the pack --create-time implementation and revisit the prioritization.

[plebcity]

Created pull request to fix this issue: #34511