builder: add gitlab-runner

hosts/builder/default.nix

@@ -17,6 +17,7 @@
     extraGroups = [
       "networkmanager"
       "wheel"
+      "docker"
     ];
   };
 
@@ -245,4 +246,17 @@
       };
     };
   };
+
+  services.gitlab-runner.enable = true;
+  # runner for everything else
+  #
+  sops.secrets."gitlab_runner_token".sopsFile = ./secrets.yaml;
+  services.gitlab-runner.services.default = {
+    # File should contain at least these two variables:
+    authenticationTokenConfigFile = config.sops.secrets."gitlab_runner_token".path;
+    dockerImage = "alpine:latest";
+    dockerVolumes = [
+      "/var/run/docker.sock:/var/run/docker.sock"
+    ];
+  };
 }