ci.yml

name: CI

on:
  push:
    branches: ["main"]
  pull_request:
    branches: ["main"]

jobs:
  checks:
    runs-on: ubuntu-latest
    steps:
      - name: checkout
        uses: actions/checkout@v4

      - name: Install Nix
        uses: cachix/install-nix-action@v24

      - name: Nix Format Check
        run: nix fmt -- . --check

      - name: Nix Syntax Check
        run: nix flake check

  build-plan:
    # Save some computation. If the checks fail, don't build.
    needs: checks
    runs-on: ubuntu-latest
    outputs:
      attrs: ${{ steps.plan.outputs.ATTRS }}
    steps:
      - name: checkout
        uses: actions/checkout@v4

      - name: Install Nix
        uses: cachix/install-nix-action@v24
        with:
          nix_path: nixpkgs=channel:nixos-23.11

      - name: Build and Cache Attic
        if: github.event_name != 'pull_request'
        run: |
          nix profile install github:zhaofengli/attic#attic
          attic login --set-default lowrisc https://nix-cache.lowrisc.org/ ${{ secrets.NIX_CACHE_TOKEN }}
          attic push public $(which attic)

      - name: Generate Nix Build Plan
        name: plan
        run: |
          echo 'ATTRS<<EOF' >> $GITHUB_OUTPUT
          nix-shell -p nix-eval-jobs --run 'nix-eval-jobs --accept-flake-config --check-cache-status --flake .#packages.x86_64-linux' | \
            tee /dev/stderr | \
            jq -s 'map(select(.isCached | not) | .attr)' | \
            tee -a $GITHUB_OUTPUT
          echo 'EOF' >> $GITHUB_OUTPUT

  build:
    needs: build-plan
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
        attr: ${{fromJSON(needs.build-plan.outputs.attrs)}}
    steps:
      - name: checkout
        uses: actions/checkout@v4

      - name: Install Nix
        uses: cachix/install-nix-action@v24

      - name: Setup Cache
        if: github.event_name != 'pull_request'
        run: |
          nix profile install github:zhaofengli/attic#attic
          attic login --set-default lowrisc https://nix-cache.lowrisc.org/ ${{ secrets.NIX_CACHE_TOKEN }}

      - name: Build
        run: nix build ".#${{ matrix.attr }}" --accept-flake-config

      - name: Upload Cache
        if: github.event_name != 'pull_request'
        run: |
          attic push public result/