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Neovim in Devcontainer

What is Devcontainer?​

Disclaimer​

  • You don't need Devcontainer to do development using Neovim inside a container

Why Devcontainers?​

  • Reproducible development environment
  • Easy to add features
  • Managing containers are easy
  • Environment could be as simple as the base image or as complex as a compose file with multiple services
  • Support editor integration

Can I use Neovim?​

  • Is there a terminal? Then yes
  • Remote access to Neovim is also possible but you need to handle the port mapping by yourself
# Server:
nvim --listen 0.0.0.0:8888 --headless
# Client:
nvim --server localhost:8888 --remote-ui

How to use Neovim​

  • Create the devcontainer spec inside the project .devcontainer/devcontainer.json
{
  "name": "spring boot container",
  "image": "ubuntu:latest",
  "features": {
    "ghcr.io/s1n7ax/devcontainer-features/jdk21:0": {},
    "ghcr.io/s1n7ax/devcontainer-features/neovim-essentials:0": {},
    "ghcr.io/s1n7ax/devcontainer-features/neovim:0": {},
    "ghcr.io/s1n7ax/devcontainer-features/astronvim:0": {}
  }
}
  • Start the container
devcontainer up --workspace-folder .
  • Start up Neovim
devcontainer exec --workspace-folder . nvim

Other Useful Devcontainer Options​

  • --remove-existing-container - to rebuilds the image
devcontainer up --workspace-folder . --remove-existing-container
  • --mount - to mount neovim user config
devcontainer up --workspace-folder . --mount 'type=bind,source=/home/s1n7ax/.config/astronvim,target=/root/.config/astronvim'
  • --additional-features - if you don't want to edit the devcontainer.json but want to use Neovim, use this flag to add additional features
devcontainer up --workspace-folder . --additional-features '{ "ghcr.io/s1n7ax/devcontainer-features/lookatme:0": {}" }'
  • --dotfiles-repository - personalize the container with your dotfiles
devcontainer up --workspace-folder . --dotfiles-repository "https://github.com/s1n7ax/dothome.git"

Challenges of Creating features​

  • Dependency of features?

    • installsAfter to mark dependencies of a feature but these will be ignored if devcontainer.json does not use theme

      # this is a part of the astronvim feature
      # devcontainer-feature.json
      "installsAfter": [
          "ghcr.io/s1n7ax/devcontainer-features/neovim-essentials:0",
          "ghcr.io/s1n7ax/devcontainer-features/neovim:0"
      ]
      # devcontainer.json
      {
        "name": "Ubuntu image just for demo",
        "image": "ubuntu:latest",
        "features": {
          "ghcr.io/s1n7ax/devcontainer-features/jdk21:0": {},
          "ghcr.io/s1n7ax/devcontainer-features/neovim-essentials:0": {},
          "ghcr.io/s1n7ax/devcontainer-features/neovim:0": {},
          "ghcr.io/s1n7ax/devcontainer-features/astronvim:0": {}
        }
      }
      • It appears devcontainer supposed to be self contained?

  • Features works only on the targeted base images

  • No build logs on test success

Disadvantages​

  • Containers does not completely resolve package conflicts
  • While it's fun to plug in features, not so much to create them
  • Containers are not 100% reproducible