[RFC #0105] - Dockerfiles

[natalieparellano]

RFC #0105 - Dockerfiles

📖 🌎 For a brief tour of what has shipped so far, consult these docs

Phase 1 - switching the run image

In this phase of the implementation, image extensions may output run.Dockerfiles in order to switch the runtime base image based on which buildpacks detected.
The detector binary should run /bin/detect for buildpacks and extensions, run /bin/generate for extensions, and determine the new run image from the generated Dockerfiles.

Spec:

• Platform api changes to support phase 1 of Dockerfiles implementation spec#308
• Buildpack api changes to support phase 1 of Dockerfiles implementation spec#307
• Released in platform API version 0.10
• Released in buildpack API version 0.9

Lifecycle:

• Support Dockerfiles (phase 1) lifecycle#849

Phase 2 - extending the build image

In this phase of the implementation, image extensions may output build.Dockerfiles in order to extend the build time base image.
The extender binary, running as root, should apply the Dockerfiles in the order determined during detect, and then drop privileges before executing the build phase.

Spec:

• Platform api changes to support phase 2 of Dockerfiles implementation spec#320
• Buildpack api changes to support phase 2 of Dockerfiles implementation spec#321
• Released in platform API version 0.10
• Released in buildpack API version 0.9

Lifecycle:

• Dockerfiles phase 2 lifecycle#896
• Released in lifecycle version 0.15

Pack:

• pack builder create should support extensions pack#1468 (more important, PR in progress)
• pack should support platform 0.10 pack#1469 (more important, PR in progress)
• pack should support pack extension * commands pack#1470
• pack inspect when image built with extensions should show the extensions pack#1486
• pack builder inspect should show extensions if they are present pack#1488
• pack build should support --extension pack#1551
• Released in pack version 0.30.0

Samples:

• Create sample apps with dockerfiles, hooks, etc  samples#112 (PR in progress)

Documentation:

• Document Dockerfiles feature (phase 1) docs#501 (PR in progress)
• Static image extensions should be documented docs#530

Phase 3 - extending the run image

In this phase of the implementation, image extensions may output Dockerfiles OR run.Dockerfiles in order to extend the runtime base image.
The extender binary, running as root, should apply the Dockerfiles in the order determined during detect, and then provide a reference to the extended run image to the platform, so that the platform can provide this during the export phase.

Spec:

• Platform API changes for run image extension (Dockerfiles phase 3) spec#347
• [RFC #0105] Buildpack API changes for run image extension (Dockerfiles phase 3) spec#348
• Released in platform API version 0.12
• Released in buildpack API version 0.10

Lifecycle:

• [RFC #0105] Analyzer changes for run image extension (Dockerfiles phase 3) lifecycle#995
• [RFC #0105] Detector changes for run image extension (Dockerfiles phase 3) lifecycle#996
• [RFC #0105] Restorer changes for run image extension (Dockerfiles phase 3) lifecycle#997
• [RFC #0105] Extender changes for run image extension (Dockerfiles phase 3) lifecycle#998
• [RFC #0105] Exporter changes for run image extension (Dockerfiles phase 3) lifecycle#999
• [RFC #0105] Rebaser changes for run image extension (Dockerfiles phase 3) lifecycle#1000

Libcnb:

• TBD
• Released in libcnb version TBD

Pack:

• [RFC #0105] pack should support run image extension pack#1620
• Run images are not pulled when using extensions pack#1686

Samples:

• [RFC #0105] Provide fixtures to demonstrate run image extension samples#137

Documentation:

• [RFC #0105] Run image extension should be documented docs#558

Optimizations

• pack build --interactive should show extensions pack#1487
• If extensions are only used to extend the build image and/or switch the run image, support creator workflow (only for trusted builders, the creator would need to stay root at least until detect/generate has finished)
• Support Dockerfiles (phases 1 and 2) buildpacks-community/kpack#1047
• Buildpacks: support Dockerfiles tektoncd/catalog#1096
• [RFC #0105] pack should support build image extension with Docker pack#1623 (mentorship project)

[cmoulliard]

Should we also include a link to a paketo's github EPIC as they will also have to support extensions Dockerfiles ?