/cnb/lifecycle/creator with SOURCE_DATE_EPOCH env var not working

[uqix]

Summary

According to the spec here https://github.com/buildpacks/spec/blob/main/platform.md#exporter, I try to pass SOURCE_DATE_EPOCH env var to /cnb/lifecycle/creator:

SOURCE_DATE_EPOCH=$(date -d $CI_COMMIT_TIMESTAMP +%s) /cnb/lifecycle/creator \
  -app=$module_dir \
  -cache-image=$cache_image \
  -skip-restore=$skip_restore \
  -run-image=$run_image \
  $extra_creator_flags \
  $image

but the creation date of the resulting image is still 01/01/1980.

---

Reproduction

Steps

1. SOURCE_DATE_EPOCH=... /cnb/lifecycle/creator ...

Current behavior

Image creation date = 01/01/1980

Expected

Image creation date = <SOURCE_DATE_EPOCH>

---

Context

lifecycle version

paketobuildpacks/builder:0.3.45-base

https://github.com/paketo-buildpacks/base-builder/releases/tag/v0.3.45

Lifecycle:
  Version: 0.14.1
  Buildpack APIs:
    Deprecated: (none)
    Supported: 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8
  Platform APIs:
    Deprecated: (none)
    Supported: 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9

platform version(s)

0.9

anything else?

[jjbustamante]

@uqix Did you try setting the environment variable CNB_PLATFORM_API to 0.9?

The reason I ask is that is the only missing thing I noticed in the code to decide to use the SOURCE_DATE_EPOCH value

[uqix]

@jjbustamante Following your tips fixed the image creation date issue, but the build output files' timestamps are still zero:

[sambhav]

@uqix that is expected. The SOURCE_DATE_EPOCH only applies to the OCI config/metadata files.

[uqix]

@samj1912 thanks, so any tip for this issue?

[natalieparellano]

In theory we could in the future allow buildpacks to set metadata on a per-layer basis to have the lifecycle omit zeroing the timestamps for particular layers. But this would require an RFC...

[uqix]

I see, I misunderstood the SOURCE_DATE_EPOCH at the very first, close this issue now.