gitea actions: use cache for nix

.gitea/workflows/flake.yaml

@@ -12,11 +12,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
-      - name: Prepare for Nix installation
+      - uses: DeterminateSystems/nix-installer-action@v13
-        run: |
+      - uses: DeterminateSystems/magic-nix-cache-action@v7
-          apt-get update
-          apt-get install -y sudo
-      - uses: cachix/install-nix-action@ba0dd844c9180cbf77aa72a116d6fbc515d0e87b # v27
       - name: lint
         run: |
           nix fmt

modules/services/gitea/actions.nix

@@ -63,6 +63,11 @@ in
               runner = {
                 capacity = 3;
               };
+              cache = {
+                enabled = true;
+                host = "10.108.27.2";
+                port = 41919;
+              };
             };
           };
 
@@ -76,6 +81,10 @@ in
                   chain output {
                     type filter hook output priority 100; policy accept;
 
+                    # Allow access to the cache
+                    ip daddr 10.108.27.2 tcp dport 41919 accept
+
+                    # Drop all private traffic
                     ip daddr 10.0.0.0/8 drop
                     ip daddr 100.64.0.0/10 drop
                     ip daddr 172.16.0.0/12 drop