Nix build using flake

.github/workflows/nix.yml

@@ -0,0 +1,83 @@
+---
+name: "Nix Build"
+"on": [push, pull_request]
+jobs:
+  build:
+    strategy:
+      matrix:
+        os:
+          - ubuntu-latest
+          - macos-latest
+        nixpkgs:
+          - pinned
+          - release-21.11
+          - release-21.05
+          - nixpkgs-unstable
+      fail-fast: false
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/[email protected]
+
+      - name: Install nix
+        uses: cachix/install-nix-action@v16
+        with:
+          extra_nix_config: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+
+      - name: Link to bifrost binary cache on cachix.org
+        uses: cachix/cachix-action@v10
+        with:
+          name: bifrost
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+
+      - name: Lock the version of nixpkgs specified by the matrix
+        run: |
+          if "${{ matrix.nixpkgs }}" != "pinned"; then
+            nix flake lock --override-input nixpkgs \
+              "nixpkgs/${{ matrix.nixpkgs }}"
+          fi
+          nix flake metadata
+
+      - name: Check for well-formed flake
+        run: |
+          nix flake check
+
+      - name: Build for default python3
+        run: |
+          nix build --print-build-logs .#bifrost-py3
+
+      - name: Build with enable-debug for python3, if pinned nixpkgs
+        if: matrix.nixpkgs == 'pinned'
+        run: |
+          nix build --print-build-logs .#bifrost-py3-debug
+
+      - name: Build for python38, unless nixpkgs-unstable
+        # For unstable, 3.8 packages are no longer in the build cache
+        if: matrix.nixpkgs != 'nixpkgs-unstable'
+        run: |
+          nix build --print-build-logs .#bifrost-py38
+
+      - name: Run Python test suite
+        # Skipped during nix build because it needs network data.
+        run: |
+          cd test
+          bash download_test_data.sh
+          nix run ..#python3-bifrost -- -m bifrost.telemetry --disable
+          nix run ..#python3-bifrost -- -m unittest discover
+
+      - name: Build documentation
+        run: |
+          nix build --print-build-logs --out-link result-doc .#bifrost-doc
+
+      - name: Deploy documentation to gh-pages
+        uses: JamesIves/[email protected]
+        # Maybe only deploy if changes in doc/ folder?  (But some doc
+        # pages generated from code, so should reflect code changes?)
+        if: |
+          matrix.os == 'ubuntu-latest'
+          && matrix.nixpkgs == 'pinned'
+          && github.event_name == 'push'
+          && github.ref == 'refs/heads/master'
+        with:
+          branch: gh-pages
+          folder: result-doc/share/doc/bifrost/html

CHANGELOG

@@ -1,5 +1,6 @@
 0.10.1
  * Cleaned up the Makefile outputs
+ * Added support for configurable, reproducible building with nix
 
 0.10.0
  * Switched over to an autotools-based build system