setup-devenv

Reusable activation step for workflows that rely on Devenv-defined tooling.

It provides a fast path for pre-baked runner images and a fallback path for dynamic activation, then verifies required commands/files so jobs fail early with clear errors.

Counterpart action

setup-devenv is the runtime counterpart to bake-devenv-image:

• Use bake-devenv-image when preparing custom runner images.
• Use setup-devenv when consuming those images (or when dynamically activating Devenv).

Repository:

• https://github.com/LN-Zap/bake-devenv-image

Scope and prerequisites

This action only handles environment activation and verification.

It does not by itself:

• check out your repository
• install Nix
• install devenv
• configure binary caches (for example via Cachix)

Typical prerequisite setup is still required in your workflow before using this action. For reference, see:

• https://devenv.sh/integrations/github-actions/

Usage

- uses: actions/checkout@v5

# Typical prerequisites on GitHub-hosted runners.
- uses: cachix/install-nix-action@v31
- uses: cachix/cachix-action@v16
  with:
    name: devenv
- run: nix profile install nixpkgs#devenv

- uses: LN-Zap/setup-devenv
  with:
    mode: auto
    verify_files: README.md
    verify_commands: |
      devenv

Mode behavior:

• image: requires a pre-baked activation script at activation_script_path
• install: requires devenv already available on PATH
• auto: uses activation script when present, otherwise falls back to dynamic devenv activation

Inputs

Name	Required	Default	Description
mode	no	auto	auto, image, or install.
activation_script_path	no	/home/runner/copilot-devenv-activate.sh	Path to pre-baked activation script.
verify_files	no	''	Newline-delimited files that must exist.
verify_commands	no	devenv	Newline-delimited commands that must resolve.
runner_label_hint	no	''	Optional runner label used in error messages.

Outputs

Name	Description
activation_mode	script, fallback, or install.
activation_seconds	Activation + verification duration in seconds.
devenv_bin	Resolved devenv binary path.
verification_status	ok or failed.