Dev-Container support

[jonah-iden]

What it does

This implements a first version of the Dev-Container Support vscode offers for Theia. This can later also be used to forward arbritrary ports at container runtime

The devcontainer.json format offers alot of configuration option of which currently only a certain few are implemented.

Implemented properties are:

• image
• dockerfile/build.dockerfile (dockerfile support still needs some more testing and work regarding its options)
  • including build.args which are just passed to docker as is
• forwardPorts
• mounts

The communication with the theia backend inside the container is done through a docker exec instance to the ´dev-conatiner-server.ts´ which forwads all communcation to stdio.

Support for having multiple devcontainer files is also added

I would love some feedback on this, especially what missing features would be most important to make it most useful.

How to test

You need docker installed and started on your machine

1. open a folder in theia
2. create a new .devcontainer folder at the root
3. add a devcontainer.json and neccessary resources for it
   here is an example file using a image wich is automaticly pulled by docker

{
    "name": "test_container",
    "image": "nikolaik/python-nodejs:python3.11-nodejs20-slim",
    "forwardPorts": [4000, "3000:3003"],
    "mounts": [{"source": "some/path", "target": "/workspaces", "type": "bind" }]

}

or here is a dockerfile with its respective devcontainer.json file for testing dockerfile support:
devcontainer.json
Dockerfile.txt

4. execute Dev Containers: Reopen in Container
5. your workspace should then open inside the container

Follow-ups

Things not implemented yet which vscodes supports:

• Port forwarding at runtime (this feature is in general still missing in the remote feature) (its mostly done though, there will be a PR as soon as this one is merged)
• attaching to running containers
• Docker Compose support
• variables inside dockerconfig.json
• Showing the docker ouput, especially for when images are build through dockerfiles or pulled
• lots of smaller configuration options

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[JonasHelming]

@msujew : Once you give your approval, we will do another test, does this work for you?

[jonah-iden]

@JonasHelming Since Mark is on vacation for the rest of the Month, feel free to test it and give feedback if you find the time

[planger]

Thank you very much @jonah-iden! This is great work and already works pretty nicely.

My biggest wish would be to show the output of the docker container, to help diagnosing issues. Currently it is very hard to debug situations where the container doesn't start for some reasons, which may happen quite easily since we don't support the full devcontainer format yet.

Aside from that I have a security related question: Afais we don't protect the exposed port of the Theia backend running in the container from the outside world, or did I miss that?
If we don't, I suggest to bind at least the Theia backend port only to the local IP address by default to avoid having it exposed to the entire network.

Other than that I only have a few minor nitpicks inline.

Thanks again for your great work on this feature! This is truly a game-changer, and I'm eager to see it evolved incrementally to support more and more properties of the devcontainer format.

[planger]

It might be good to document which properties of the devcontainer format are supported at the moment or link to an issue that lists the unsupported ones.

[jonah-iden]

Thanks for the review! I'll try to add showing the output today

[jonah-iden]

@planger added a for now very basic output display. There is some messages not looking super nice but that can be improved later on

[JonasHelming]

@jonah-iden When this is ready for re-reviewe, please just trigger Philips review again

[planger]

Thank you for the additions @jonah-iden! This looks great and I think it should be good to go as a first version of this excellent feature.

[hsnoil]

@jonah-iden for this patch, are ENV variables like ${localWorkspaceFolder} and ${localEnv:HOME} suppose to work for mounting? Because it keeps saying add absolute path

https://code.visualstudio.com/remote/advancedcontainers/add-local-file-mount

[jonah-iden]

@hsnoil no sorry, variables in the devcontainer.json are not yet implemented for dev-containers.

I took a small look at it. Seems like implementing this would require a refactor or similar of the VaraibleResolverService so that it would be somehow available in the backend