feat: add standalone GitHub Action for installing Nix

.github/workflows/act-test.yml

@@ -0,0 +1,33 @@
+name: Act Test
+
+on:
+  workflow_dispatch:
+
+jobs:
+  test-release:
+    name: Test Release Mode
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install Nix from latest release
+        uses: ./
+        with:
+          no-init: true
+          add-channel: true
+
+      - name: Verify Nix installation
+        run: |
+          echo "Checking Nix is available..."
+          which nix
+          nix --version
+
+          echo "Testing nix run command..."
+          nix run nixpkgs#hello
+
+          echo "Testing nix-env install..."
+          nix-env --install hello
+          hello
+          nix-env --uninstall hello

.github/workflows/ci.yml

@@ -33,11 +33,18 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: ./.github/actions/install-nix-action
+        uses: ./
         with:
-          cachix-authtoken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+          extra-conf: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
 
 
+      - name: Setup Cachix
+        uses: cachix/cachix-action@v15
+        with:
+          name: nix-installer
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+
       - name: Build the installer
         run: |
           if [[ $RUNNER_OS == "Linux" ]]; then
@@ -77,9 +84,16 @@ jobs:
           check-outdated: false # PRs shouldn't fail because main's nixpkgs is out of date
 
       - name: Install Nix
-        uses: ./.github/actions/install-nix-action
+        uses: ./
+        with:
+          extra-conf: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+
+      - name: Setup Cachix
+        uses: cachix/cachix-action@v15
         with:
-          cachix-authtoken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+          name: nix-installer
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
 
       - name: Check rustfmt
         run: nix develop --command check-rustfmt
@@ -146,13 +160,15 @@ jobs:
           fi
 
       - name: Initial install
-        uses: ./.github/actions/install-nix-action
+        uses: ./
         with:
-          cachix-authtoken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
           dogfood: true
           dogfood-path: ${{ steps.download-installer.outputs.download-path }}
-          use-cache: false
           no-init: ${{ matrix.no-init }}
+          add-channel: true
+          verbosity: 2
+          extra-conf: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
 
       - name: Ensure daemon was not configured with init
         if: ${{ matrix.no-init != '' }}
@@ -191,13 +207,15 @@ jobs:
           fi
 
       - name: Repeated install
-        uses: ./.github/actions/install-nix-action
+        uses: ./
         with:
-          cachix-authtoken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
           dogfood: true
           dogfood-path: ${{ steps.download-installer.outputs.download-path }}
-          use-cache: false
           no-init: ${{ matrix.no-init }}
+          add-channel: true
+          verbosity: 2
+          extra-conf: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
 
       - name: echo $PATH
         run: echo "$PATH"
@@ -206,6 +224,8 @@ jobs:
       - name: Test installation
         if: ${{ matrix.no-init == '' }}
         run: |
+          set -x
+          echo $PATH
           nix-shell -p hello --command hello
           nix-env --install hello
           hello
@@ -276,11 +296,20 @@ jobs:
           find "$INSTALL_ROOT" -type f -exec chmod +x {} +
 
       - name: Initial install
-        uses: ./.github/actions/install-nix-action
+        uses: ./
         with:
-          cachix-authtoken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
           dogfood: true
           dogfood-path: ${{ steps.download-installer.outputs.download-path }}
+          add-channel: true
+          verbosity: 2
+          extra-conf: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+
+      - name: Setup Cachix
+        uses: cachix/cachix-action@v15
+        with:
+          name: nix-installer
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
 
       - run: nix flake check -L
       - run: |

.github/workflows/release-script.yml

@@ -14,9 +14,13 @@ jobs:
     steps:
     - name: Checkout
       uses: actions/checkout@v4
-    - uses: cachix/install-nix-action@v25
+    - name: Install Nix
+      uses: ./
+    - name: Setup Cachix
+      uses: cachix/cachix-action@v15
       with:
-        cachix-authtoken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+        name: nix-installer
+        authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
     - name: Create draft release
       # The script also depends on gh and git but those are both pre-installed on the runner
       run: nix run --inputs-from .# nixpkgs#python3 -- assemble_installer.py "${{ github.event.inputs.testing_hydra_eval_id }}"

.github/workflows/update.yml

@@ -14,9 +14,12 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: ./.github/actions/install-nix-action
+        uses: ./
+      - name: Setup Cachix
+        uses: cachix/cachix-action@v15
         with:
-          cachix-authtoken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+          name: nix-installer
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
       - name: Check flake
         uses: DeterminateSystems/flake-checker-action@main
       - name: Update flake.lock

README.md

@@ -215,6 +215,31 @@ podman rmi $IMAGE
 With some container tools, such as [Docker], you can omit `sandbox = false`.
 Omitting this will negatively impact compatibility with container tools like [Podman].
 
+### In GitHub Actions
+
+This repository provides a GitHub Action for installing Nix in CI workflows.
+
+**Basic usage:**
+```yaml
+- uses: NixOS/experimental-nix-installer@main
+```
+
+**Install specific version:**
+```yaml
+- uses: NixOS/experimental-nix-installer@main
+  with:
+    installer-version: v3.11.3-experimental-prerelease
+```
+
+**No-init mode (for containers):**
+```yaml
+- uses: NixOS/experimental-nix-installer@main
+  with:
+    no-init: true
+```
+
+See the [action inputs](action.yml) for all available options.
+
 ### In WSL2
 
 We **strongly recommend** first [enabling systemd][enabling-systemd] and then installing Nix as normal: