[feature] Enable passing --metadata-file arg to devcontainer build

[Thacai]

Hi,

As we're using private registry, Jfrog Artifactory, we want to publish build info after devcontainer has been build, and pushed, so that JFrog can properly track the containers dependencies.

But currently there doesn't seem to be a straight forward way to make devcontainer build command export the metadata file, needed for input to JFrog CLI jf rt build-docker-create --image-file command.
It's possible using native docker buildx build (reference: https://docs.docker.com/engine/reference/commandline/buildx_build/#metadata-file)

I would like to be able to pass it like this: devcontainer build --image-name ${IMAGE}:${TAG} --workspace-folder "src/${IMAGE}/" --metadata-file metadata.json

If this is already possible with some temporary workarounds, I'd like to know how.

[chrmarti]

--metadata-file could be passed along to our spawning of docker buildx build the same way we pass along --platform --push and --output.

cli/src/spec-node/devContainersSpecCLI.ts

Line 461 in 6bbaf36

'platform': { type: 'string', description: 'Set target platforms.' },

[Thacai]

That would be great

[michael-herwig]

Hi @chrmarti, what’s the status of this one?
I tried updating the feature implementation to the current main branch — the MR is linked. Please take it with a grain of salt, since I’m not very proficient in the TypeScript ecosystem. I just aligned the implementation with the existing buildxCacheTo option.