Optional features (feature groups).

[Softyy]

[Proposal] Optional features (feature groups)

One of the shortcomings I've encountered is allowing for slight differences in ci workflows vs local workflows. I was thinking of adding an additional property to the devcontainer-feature.json spec that would allow for grouping features between the two environments. Namely, allow for a subset of features to be used in ci workflows via cli flags.

Proposal

Extend the devcontainer-feature.json spec with the following property:

Property	Type	Description
group	string	Optional Metadata used for excluding this feature.

Example

Consider a devcontainer used for maintaining a gitops related repo. Locally one requires secret management and some manual handling tools, but in CI these tools are not required. A user would mark the features not needed for CI via a group named local. Ref:

devcontainer.json

{
    ...
    "features": {
        "ghcr.io/devcontainers/features/aws-cli:1": {"group": "local"},
        "ghcr.io/devcontainers/features/docker-outside-of-docker:1": {"group": "local"},
        "ghcr.io/devcontainers-contrib/features/sops:1": {"group": "local"},
        "ghcr.io/devcontainers/features/node:1": {
            "version": "lts"
        }
    },
    ...
}

When it comes to starting the devcontainer locally, there would be no change to existing behaviour. In CI, one would pass in the flag:

> devcontainer up --exclude-group local

This would spin up the devcontainer without the features in the local group.

Plan

I don't mind putting up a couple PRs across the various repo's (cli , ci) to make this a reality, but I'm looking for a green light on the work before I put in the time. Anyhow, I'm open to any feedback, e.g. make the system more extensible with include and exclude or whatever.