feat(action): Add extra-nix-config input for custom nix.conf settings

.github/workflows/test.yaml

@@ -94,3 +94,17 @@ jobs:
           sha256-checksum: '169836de22c41a1c68ac5a43e0514d4021137647c7c08ee8bd921faa430ee286'
           project-path: 'testdata'
           disable-nix-access-token: "${{ github.ref != 'refs/heads/main' }}"
+
+  test-action-with-extra-nix-config:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install devbox with extra nix config "user-agent-suffix = test-suffix"
+        uses: ./
+        with:
+          devbox-version: 0.13.6
+          project-path: 'testdata'
+          extra-nix-config: user-agent-suffix = test-suffix
+      - name: Check nix user-agent-suffix config
+        run: |
+          [[ "$(nix config show user-agent-suffix)" == "test-suffix" ]]

README.md

@@ -40,10 +40,11 @@ jobs:
 | sha256-checksum          | Specify an explicit checksum for the devbox binary                                    |                       |
 | disable-nix-access-token | Disable configuration of nix access-tokens with the GitHub token used in the workflow | false                 |
 | skip-nix-installation    | Skip the installation of nix                                                          | false                 |
+| extra-nix-config         | Gets appended to `nix.conf` if passed                                                 |                       |
 
-### Example Configuration
+### Example Configurations
 
-Here's an example job with all inputs:
+Here's an example job with most inputs:
 
 ```
 - name: Install devbox
@@ -56,3 +57,17 @@ Here's an example job with all inputs:
     disable-nix-access-token: 'false'
     sha256-checksum: <checksum>
 ```
+
+#### Usage on a GitHub Enterprise Server
+
+On a privately hosted GitHub Enterprise Server, the `github.token` available in the context is not valid for accessing `api.github.com`, 
+which can lead to failures due to the rate-limit for unauthenticated requests. To work around this, you can provide a personal access token
+for `api.github.com` in the `extra-nix-config` input.
+Additionally, it might be necessary to provide a token for your GitHub Enterprise Server, if you are using Nix packages from there.
+
+```
+- name: Install devbox
+  uses: jetify-com/[email protected]
+  with:
+    extra-nix-config: access-tokens = my-github-enterprise-server.example.com=${{ github.token }} github.com=${{ secrets.MY_GITHUB_COM_TOKEN }}
+```

action.yml

@@ -25,6 +25,9 @@ inputs:
   skip-nix-installation: # 'true' or 'false'
     description: 'Skip the installation of nix'
     default: 'false'
+  extra-nix-config:
+    description: 'Gets appended to `nix.conf` if passed'
+    default: ''
 
 runs:
   using: "composite"
@@ -126,12 +129,19 @@ runs:
         fi
 
     - name: Configure nix access-tokens
-      if: inputs.disable-nix-access-token == 'false'
+      if: inputs.disable-nix-access-token == 'false' && github.server_url == 'https://github.com'
       shell: bash
       run: |
         mkdir -p ~/.config/nix
         echo "access-tokens = github.com=${{ github.token }}" >> ~/.config/nix/nix.conf
 
+    - name: Configure nix extra config
+      if: inputs.extra-nix-config != ''
+      shell: bash
+      run: |
+        mkdir -p ~/.config/nix
+        echo "${{ inputs.extra-nix-config }}" >> ~/.config/nix/nix.conf
+
     - name: Install nix
       if: inputs.skip-nix-installation == 'false'
       uses: DeterminateSystems/nix-installer-action@e50d5f73bfe71c2dd0aa4218de8f4afa59f8f81d  # v16
@@ -165,7 +175,7 @@ runs:
       shell: bash
       run: |
         devbox run --config=${{ inputs.project-path }} -- echo "Packages installed!"
-    
+
     - name: List nix store cache on failure
       shell: bash
       if: failure()