Support docker:// URIs for builder lifecycle parameter

[braunsonm]

Description

Right now we can provide a docker:// URI for the buildpacks listed in a builder inside the builder.toml but we cannot do the same thing with the lifecycle.

Proposed solution

[lifecycle]
  uri = "docker://buildpacksio/lifecycle:0.18.5"

Describe alternatives you've considered

Right now you need to provide a link to the tar.gz and cannot use docker images.

Additional context

The reason this would be a great quality of life feature is primarily because almost all the other fields in the specification allow docker:// archives. This would be consistent and not require a separate location for storage of the lifecycle binaries. It is a bit inconsistent that at build time you are able to specify a custom lifecycle image, but you can't do the same when you are packaging a builder.

[jjbustamante]

• The method responsible for fetching the lifecycle during builder creation is here
• It seems safe to add the corresponding logic to process the new protocol type
• On the other hand, the logic that handles docker:// when fetching buildpacks is here

[prashantrewar]

Hey @jjbustamante, I want to give it a try. Could you please assign this to me?

[rashadism]

Hi @jjbustamante , I would like to take a look if this is available

[natalieparellano]

@prashantrewar were you still working on this one, or could @rashadism have it?

[prashantrewar]

@natalieparellano, I apologize, I'm busy with something. @rashadism you can feel free to try it.

Thank you!

[rashadism]

@jjbustamante @natalieparellano Hi can u review the PR