nix: allow port forwarding configuration

We add a nixos module to the testing modules. This allows configuring
ports for port forwarding for the dashboard and the serialproxy.

This way, users can access the dashboard and the web serial console on
the host when running the OpenStack controller in a VM.

Author: hertrste

modules/testing/default.nix

@@ -38,6 +38,52 @@ let
         environment.variables = adminEnv;
       };
     };
+
+  portForwarding =
+    { config, lib, ... }:
+    with lib;
+    let
+      cfg = config.openstack-testing;
+    in
+    {
+      options.openstack-testing = {
+        enable = mkEnableOption "Enable port forwarding." // {
+          default = true;
+        };
+        dashboardHostPort = mkOption {
+          default = 8080;
+          type = types.port;
+          description = ''
+            Host port to make the OpenStack dashboard accessible when running
+            the OpenStack controller in a VM. Dashboard can be accessed via:
+            localhost:<dashboardHostPort>
+          '';
+        };
+        serialProxyHostPort = mkOption {
+          default = 6083;
+          type = types.port;
+          description = ''
+            Host port to make the web console feature available for the
+            OpenStack dashboard. Changing the value might requires to change
+            the configuration of the dashboard.
+          '';
+        };
+      };
+      config = mkIf cfg.enable {
+        virtualisation.forwardPorts = [
+          {
+            from = "host";
+            host.port = cfg.dashboardHostPort;
+            guest.port = 80;
+          }
+          {
+            from = "host";
+            host.port = cfg.serialProxyHostPort;
+            guest.port = 6083;
+          }
+        ];
+      };
+    };
 in
 {
   testController =
@@ -49,7 +95,10 @@ in
       };
     in
     {
-      imports = [ common ];
+      imports = [
+        common
+        portForwarding
+      ];
 
       virtualisation = {
         cores = 4;