Nix CI

CI Setup

When the user asks to set up CI, use the Ask tool to prompt them to choose:

1. GitHub public runners — CI via GitHub Actions
2. Vira self-hosted — self-hosted CI using Vira

Option 1: GitHub Actions

Use the install-nix action (avoid DetSys actions) and invoke Vira to build:

# .github/workflows/ci.yml
name: CI
on: [push, pull_request]
jobs:
  build:
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest]
    runs-on: ${{ matrix.os }}
    steps:
      - uses: actions/checkout@v4
      - uses: nixbuild/nix-quick-install-action@v34
      - run: nix profile install github:juspay/vira
      - run: vira ci

Option 2: Vira Self-Hosted

Vira is already running and pointed at the repo. Create a vira.hs file in the repo root to configure the build pipeline.

Before generating vira.hs, you MUST fetch and read https://vira.nixos.asia/config to understand the exact DSL format. Do not guess the syntax.

Rules for generating vira.hs

• If the repo has a git remote pointing to GitHub, set signoff.enable = True
• If multiple flake.nix files exist (e.g., in subdirectories), add all of them to build.flakes with appropriate overrideInputs settings
• Leave cache.url = Nothing with a comment -- TODO: configure Attic cache URL
• Use the Ask tool to ask the user whether build.systems should be set to ["x86_64-linux", "aarch64-darwin"] for multi-platform builds

After creating vira.hs, run vira ci -b to verify the configuration.