feat: add envbuilder install-feature command

[phorcys420]

I am looking into adding a module to the registry that would let template administrators install Dev Container features inside Coder Workspaces (even outside of envbuilder).

I think envbuilder already has the logic to install features, so I think the most logical thing to do would be to create a separate command just to install a given feature.

While Dev Container features are only shell scripts, there is still some logic needed for arguments in the manifest, e.g dependsOn.

See coder/modules#307 for more context.

Usage

envbuilder install-feature <source>
Ideally, source could be either a Git URL, a local folder or a path to an image.

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cc: @johnstcn

[mafredri]

How would this module work, would it require the envbuilder binary to be present or will it download and install envbuilder first, then attempt to install the feature?

One issue with installing features is permissions, i.e. envbuilder probably has to be run with sudo to work properly, otherwise users may end up with none or only partially working features.

That said, I think this is a pretty cool feature request, thanks for opening the ticket @phorcys420.

[phorcys420]

How would this module work, would it require the envbuilder binary to be present or will it download and install envbuilder first, then attempt to install the feature?

Probably download and install, but i haven't really decided.

One issue with installing features is permissions, i.e. envbuilder probably has to be run with sudo to work properly, otherwise users may end up with none or only partially working features.

Devcontainer features expect to be run as root anyways so it will always need sudo access.