Configuring multiple languages in a single repository devcontainer

[Sup2point0]

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This is how using the Codespaces: Add Dev Container Configuration Files command configured ./.devcontainer/devcontainer.json for a project being developed in Codespaces:

{
  "name": "Python 3",
  "image": "mcr.microsoft.com/devcontainers/python:1-3.12-bookworm"
}

Later on, the project required another programming language, but I could not figure out how to add another language configuration.

I read Introduction to devcontainers, the individual pages for each language and the devcontainers specification, but did not find anything relating to multiple language configurations.

I finally found an archived issue which alerted me to the solution using features:

{
  "name": "Python 3",
  "image": "mcr.microsoft.com/devcontainers/python:1-3.12-bookworm"
  "features": {
    "ghcr.io/devcontainers/features/ruby:1"
  }
}

This works, although whether or not the additional languages are installed seems to be on-off (could just be an issue on my end).

Does it make any difference, then, where you define a language configuration? What’s the difference between something installed with image and features? What’s the standard way of configuring multiple languages for a single devcontainer?

Furthermore, figuring out how to configure multiple languages was not easy given the lack of any mention at all in the docs. It seems like a pretty common thing you might need to do, so explicitly showing beginners how to do it would be helpful. Perhaps a section or note could added in Introduction to devcontainers detailing how to go about it?

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