DevContainer Composer

Generate a ready-to-use .devcontainer/ for any folder. Tick the packages you need in a panel (Node.js, TypeScript, Python, Azure CLI, azd, AWS CLI, Copilot, ...). The generated container keeps your CLI logins, GitHub Copilot state and shell history across restarts and rebuilds.

Quick start

1. Open a folder in VS Code. It can be empty.
2. Click Dev Container (package icon) in the status bar, or run DevContainer Composer: Create / Edit Dev Container.
3. Choose packages and versions, then click Generate .devcontainer.
4. Click Reopen in Container. This needs the Dev Containers extension.

If you don't need the panel, use Generate Dev Container with Default Packages. If a .devcontainer already exists, it opens the panel instead of overwriting anything.

What gets generated

.devcontainer/
  devcontainer.json   features, mounts, extensions, postCreateCommand, stored selection
  Dockerfile          managed block between markers; your own lines below the end marker are kept
  post-create.sh      volume ownership fix, symlinks, package setup, then post-create.local.sh if present
  .gitattributes      LF line endings for *.sh and Dockerfile

Put your own setup steps in .devcontainer/post-create.local.sh. The extension never overwrites that file.

Persistence

Two Docker volumes are mounted:

Each home path is a symlink into its volume, so you log in once and the login is reused by every project. ${devcontainerId} stays the same when you rebuild, so project state survives Rebuild Container. You can turn off persistence completely, or switch off single items, in the panel.

Corporate networks

Under Package sources you can set:

• an npm registry (NPM_CONFIG_REGISTRY)
• a pip index and trusted host (PIP_INDEX_URL, PIP_TRUSTED_HOST)
• an image mirror, which replaces mcr.microsoft.com
• a feature mirror, which replaces ghcr.io

These settings are written to the Dockerfile as ENV lines, so they apply while features install and inside the container. Defaults come from the devcontainerComposer.sources.* settings.

Some Dev Container Features download binaries directly from vendor hosts (nodejs.org, packages.microsoft.com, github.com, files.pythonhosted.org). Your proxy must allow those hosts, or your mirror must cache them.

Re-running on an existing .devcontainer

• devcontainer.json is edited in place, so comments and unknown keys are kept.
• Features, extensions and mounts you added yourself are kept. Items the extension added earlier are removed when you deselect them.
• An existing postCreateCommand is kept and runs in parallel with post-create.sh.
• A Dockerfile without markers is only replaced after you confirm, and a backup is saved as Dockerfile.bak.
• dockerComposeFile setups are not supported yet.

Settings

Save as my default in the panel writes the current selection to these settings.

Custom packages

"devcontainerComposer.customPackages": [
  {
    "id": "rust",
    "label": "Rust",
    "category": "Languages",
    "feature": "ghcr.io/devcontainers/features/rust:1",
    "versions": ["latest", "1.80"],
    "extensions": ["rust-lang.rust-analyzer"],
    "persist": [{ "id": "cargo-registry", "path": ".cargo/registry", "scope": "shared" }]
  },
  {
    "id": "corp-tools",
    "label": "Company tools",
    "install": "pip install --user corp-cli==${version}",
    "versions": ["2.1.0"],
    "requires": ["python"]
  }
]

A custom package with the same id as a built-in one replaces the built-in one.

Development

See PROJECT.md in the repository for the design and architecture.

npm install
npm run typecheck
npm test          # unit tests (node:test)
npm run build     # esbuild bundle to dist/extension.js
npm run package   # .vsix

Press F5 to start an Extension Development Host. The end-to-end test needs Docker; see e2e/run-e2e.sh and e2e/run-e2e.ps1.