Proposal: Allow using env-vars in devcontainer-feature.json

[max06]

My current use case involves defining additional container mounts in the future users home directory in the container. It seems to be impossible at the moment, since the remoteUser is configurable.

${devcontainerId} seems to be the only variable that can be used in the devcontainer-feature.json file. There are 2 env variables mentioned in the feature spec (_REMOTE_USER_HOME and _CONTAINER_USER_HOME) but they are only accessible in the install.sh-script.

I'd like to have access to more variables, either the ones passed to the install-script, or the ones used in the parents devcontainer.json.

[samruddhikhandale]

Hi 👋

I agree, it would be helpful if we could make environment variables passed to the devcontainer.json and added as Feature options available to devcontainer-feature.json.

Our current set of dev container Features would benefit from this as well, we have devcontainers/cli#391 opened which tries to tackle another such scenario.

[max06]

Hello there, once again... can I do something to get this going? I'd love to finish some devcontainer features but they depend on these variables...

[samruddhikhandale]

Hi 👋

We currently have this issue in our backlog, @bamurtaugh @joshspicer looking for your thoughts on this one.

[bamurtaugh]

I agree this one sounds useful, thanks for opening @max06!

Since this is an open spec, we really value feedback and contributions too. @samruddhikhandale @chrmarti would you find it reasonable to suggest anyone from the community could also contribute this request via PR to https://github.com/devcontainers/cli? If so, then @max06 you'd be able to kick this off directly!

[max06]

Oh boy!

Alright, I'll give it a try 😅

[max06]

Looks like I overestimated my abilities here 🙈
(Any help/hint would be greatly appreciated!)

[natescherer]

Adding another use case here, would be great to be able to use ${localEnv:HOME}${localEnv:USERPROFILE} for the mounts in features. I'm working on a feature to allow adding Python packages using a requirements.txt and it would be great to be able to give users the options to use a requirements.txt that's store on their host rather than in the container. Don't see a way to accomplish this otherwise.

[max06]

I gave it another try - and was more successful than last time🥳