feat(john-endesktop): add harmonia binary cache service

Replace broken k8s harmonia deployment with native NixOS service.

Configuration:
- services.harmonia.enable = true
- Bind to [::]:5000 (IPv4 and IPv6)
- Sign key at /etc/harmonia/signing-key.private
- Open firewall port 5000

The signing key must be placed manually on john-endesktop at
/etc/harmonia/signing-key.private using the key generated earlier.

Closes: x-fqaob

.gitea/workflows/ci.yml

@@ -18,3 +18,50 @@ jobs:
         run: nix flake check
         env:
           NIX_CONFIG: "access-tokens = git.johnogle.info=${{ secrets.GITEA_ACCESS_TOKEN }}"
+
+  build-and-cache:
+    runs-on: ubuntu-latest
+    needs: check
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    strategy:
+      fail-fast: false
+      matrix:
+        machine:
+          - nix-book
+          - boxy
+          - zix790prors
+          - nix-deck
+          - john-endesktop
+          - live-usb
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: https://git.johnogle.info/johno/gitea-actions/nix-setup@v1
+
+      - name: Build ${{ matrix.machine }}
+        id: build
+        run: |
+          OUT_PATH=$(nix build .#nixosConfigurations.${{ matrix.machine }}.config.system.build.toplevel --no-link --print-out-paths)
+          echo "out_path=$OUT_PATH" >> "$GITHUB_OUTPUT"
+        env:
+          NIX_CONFIG: "access-tokens = git.johnogle.info=${{ secrets.GITEA_ACCESS_TOKEN }}"
+
+      - name: Sign and push to cache
+        run: |
+          # Write signing key
+          echo "${{ secrets.NIX_SIGNING_KEY }}" > /tmp/signing-key
+          chmod 600 /tmp/signing-key
+
+          # Sign the closure
+          nix store sign --key-file /tmp/signing-key -r "${{ steps.build.outputs.out_path }}"
+
+          # Setup SSH key for cache push
+          mkdir -p ~/.ssh
+          echo "${{ secrets.CACHE_SSH_KEY }}" > ~/.ssh/cache_key
+          chmod 600 ~/.ssh/cache_key
+          ssh-keyscan -H ${{ secrets.CACHE_HOST }} >> ~/.ssh/known_hosts 2>/dev/null || true
+
+          # Push to cache
+          nix copy --to "ssh-ng://${{ secrets.CACHE_USER }}@${{ secrets.CACHE_HOST }}?ssh-key=$HOME/.ssh/cache_key" "${{ steps.build.outputs.out_path }}"
+        env:
+          NIX_CONFIG: "access-tokens = git.johnogle.info=${{ secrets.GITEA_ACCESS_TOKEN }}"

machines/john-endesktop/configuration.nix

@@ -54,6 +54,7 @@ with lib;
       4000  # nfs callback
       4001  # nlockmgr
       4002  # mountd
+      5000  # harmonia binary cache
       20048 # mountd
     ];
     allowedUDPPorts = [
@@ -148,6 +149,16 @@ with lib;
     };
   };
 
+  # Harmonia binary cache server
+  # Replaces the broken k8s deployment with native NixOS service
+  services.harmonia = {
+    enable = true;
+    signKeyPath = "/etc/harmonia/signing-key.private";
+    settings = {
+      bind = "[::]:5000";
+    };
+  };
+
   # Time zone
   time.timeZone = "America/Los_Angeles"; # Adjust as needed
 

roles/common.nix

@@ -26,7 +26,7 @@
           "https://nix-cache.johnogle.info"
         ];
         trusted-public-keys = [
-          "nix-cache.johnogle.info-1:IC5x8BxnrqkU9XqhMdDnZLtSg9Y3rBJVXhve5DJ92J0="
+          "nix-cache.johnogle.info-1:G0ZGQwcSC4+4SDDFHZI/ZX3a6uFrs/5cjA5Jvaypj0I="
         ];
         fallback = true;
         connect-timeout = 5;