Use pixi inside of a devcontainer

VSCode Devcontainers are a popular tool to develop on a project with a consistent environment. They are also used in GitHub Codespaces which makes it a great way to develop on a project without having to install anything on your local machine.

To use pixi inside of a devcontainer, follow these steps:

Create a new directory .devcontainer in the root of your project. Then, create the following two files in the .devcontainer directory:

.devcontainer/Dockerfile

FROM mcr.microsoft.com/devcontainers/base:jammy

ARG PIXI_VERSION=v0.39.3

RUN curl -L -o /usr/local/bin/pixi -fsSL --compressed "https://github.com/prefix-dev/pixi/releases/download/${PIXI_VERSION}/pixi-$(uname -m)-unknown-linux-musl" \
    && chmod +x /usr/local/bin/pixi \
    && pixi info

# set some user and workdir settings to work nicely with vscode
USER vscode
WORKDIR /home/vscode

RUN echo 'eval "$(pixi completion -s bash)"' >> /home/vscode/.bashrc

.devcontainer/devcontainer.json

{
    "name": "my-project",
    "build": {
      "dockerfile": "Dockerfile",
      "context": "..",
    },
    "customizations": {
      "vscode": {
        "settings": {},
        "extensions": ["ms-python.python", "charliermarsh.ruff", "GitHub.copilot"]
      }
    },
    "features": {
      "ghcr.io/devcontainers/features/docker-in-docker:2": {}
    },
    "mounts": ["source=${localWorkspaceFolderBasename}-pixi,target=${containerWorkspaceFolder}/.pixi,type=volume"],
    "postCreateCommand": "sudo chown vscode .pixi && pixi install"
}

Put .pixi in a mount

In the above example, we mount the .pixi directory into a volume. This is needed since the .pixi directory shouldn't be on a case insensitive filesystem (default on macOS, Windows) but instead in its own volume. There are some conda packages (for example ncurses-feedstock#73) that contain files that only differ in case which leads to errors on case insensitive filesystems.

Secrets

If you want to authenticate to a private conda channel, you can add secrets to your devcontainer.

.devcontainer/devcontainer.json

{
    "build": "Dockerfile",
    "context": "..",
    "options": [
        "--secret",
        "id=prefix_dev_token,env=PREFIX_DEV_TOKEN",
    ],
    // ...
}

.devcontainer/Dockerfile

# ...
RUN --mount=type=secret,id=prefix_dev_token,uid=1000 \
    test -s /run/secrets/prefix_dev_token \
    && pixi auth login --token "$(cat /run/secrets/prefix_dev_token)" https://repo.prefix.dev

These secrets need to be present either as an environment variable when starting the devcontainer locally or in your GitHub Codespaces settings under Secrets.