Extend - Buildpacks — ContextQMD

+++ title="Extend" weight=9 +++

The extender applies Dockerfiles output by image extensions to the build or runtime base image.

When extending the build image:

In addition to the outputs enumerated below, outputs produced by extender include those produced by builder - as the lifecycle will run the build phase after extending the build image.
Platforms MUST skip the builder and proceed to the exporter.

Exit Code	Result
`0`	Success
`11`	Platform API incompatibility error
`12`	Buildpack API incompatibility error
`1-10`, `13-19`	Generic lifecycle errors
`100-109`	Extension-specific lifecycle errors

For each extension in <group> in order, if a Dockerfile exists in <generated>/<buildpack-id>/<kind>.Dockerfile, the lifecycle:
- Shall apply the Dockerfile to the environment according to the process outlined in the Image Extension Specification.
- SHALL set the build context to the folder according to the process outlined in the Image Extension Specification.
The extended image must be an extension of:
- The build-image in <analyzed> when <kind> is build, or
- The run-image in <analyzed> when <kind> is run
When extending the build image, after all build.Dockerfiles are applied, the lifecycle:
- Shall proceed with the build phase using the provided <gid> and <uid>
When extending the run image, after all run.Dockerfiles are applied, the lifecycle:
- If any run.Dockerfile set the label io.buildpacks.rebasable to false or left the label unset:
  - Shall set the label io.buildpacks.rebasable to false on the extended run image
- If after the final run.Dockerfile the run image user is root,
  - Shall fail
- Shall copy the manifest and config for the extended run image, along with any new layers, to <extended>/run

For more information about the extender, see the Platform API spec.