feat: snippets

[bayou-brogrammer]

Goals

This PR adds snippets which is being discussed in #41 .

It will generate snippet lines for ONLY our containerfile module

• allow for modules to specify snippets
• append snippets to module run inside Containerfile
• write supporting test

Preview

Recipe.yml

# image will be published to ghcr.io/<user>/<name>
name: orora

description: A starting point for further customization of uBlue images. Make your own! https://ublue.it/making-your-own/

base-image: ghcr.io/ublue-os/silverblue-main
image-version: latest # latest is also supported if you want new updates ASAP

modules:
  - type: signing
    snippets:
      - COPY --from=ghcr.io/blue-build/cli:latest-installer /out/BLUEBUILD /usr/bin/BLUEBUILD

Generated Container File snippet

RUN chmod +x /tmp/modules/signing/signing.sh && source /tmp/exports.sh && /tmp/modules/signing/signing.sh '{"type":"signing","snippets":["COPY --from=ghcr.io/blue-build/cli:latest-installer /out/BLUEBUILD /usr/bin/BLUEBUILD"]}'
COPY --from=ghcr.io/blue-build/cli:latest-installer /out/BLUEBUILD /usr/bin/BLUEBUILD

[gmpinder]

Further discussions still need to be had for how to support this and for which modules:

#41

[xynydev]

I added my comment in #41 alongside some concerned questions on Discord, but here's more of a PR review:

• What's the usecase of adding snippets through the signing module? I understand this PR supports any module for snippets. Why, what's the benefit?
• Even if there is a benefit, it doesn't make sense to me to add another default key to the module configuration that isn't related to the modules functionality at all.
• This PR might be fine, though, if you refactor it to just work with the pre-existing containerfile module.