create module system for machines

flake.nix

@@ -35,7 +35,7 @@
       pkgs = nixpkgs.legacyPackages.${controllerArch};
       lib = pkgs.lib;
       pkgs-unstable = nixpkgs-unstable.legacyPackages.${controllerArch};
-      machines = import ./nixos/machines;
+      machines = (lib.modules.evalModules { modules = [ (import ./nixos/machines) ]; }).config.machines;
       physicalMachines = lib.filterAttrs (n: v: v.type == "physical") machines;
       mkNixosSystems = systemDef:
         builtins.mapAttrs

nixos/machines/default.nix

@@ -1,12 +1,64 @@
-# TODO: Create a nixos module system for this. (mkMerge)
-# That way, we don't have to specify isRaspberryPi on every machine... etc.
+{ lib, ... }:
+let
+  machineOpts = { ... }: {
+    options = {
+      # TODO: rename to kind?
+      type = lib.mkOption {
+        type = lib.types.enum [ "physical" "virtual" ];
+        description = ''
+          Whether this machine is physical or virtual.
+        '';
+      };
+
+      hypervisorName = lib.mkOption {
+        default = null;
+        type = with lib.types; nullOr str;
+        description = ''
+          The host name of the hypervisor hosting this virtual machine.
+        '';
+      };
+
+      arch = lib.mkOption {
+        default = null;
+        type = with lib.types; nullOr str;
+        description = ''
+          CPU architecture of this machine.
+        '';
+      };
+
+      isRaspberryPi = lib.mkOption {
+        default = false;
+        type = lib.types.bool;
+      };
+
+      isHypervisor = lib.mkOption {
+        default = false;
+        type = lib.types.bool;
+      };
+
+      nixosModule = lib.mkOption {
+        default = { ... }: { };
+        type = lib.types.anything;
+        description = ''
+          Customized configuration for this machine in the form of a NixOS module.
+        '';
+      };
+    };
+  };
+in
 {
+  options = {
+    machines = lib.mkOption {
+      type = with lib.types; attrsOf (submodule machineOpts);
+    };
+  };
+
+  config = {
+    machines = {
       warwick = {
         type = "physical";
         arch = "aarch64-linux";
         isRaspberryPi = true;
-    isHypervisor = false;
-    isVirtualMachine = false;
 
         nixosModule.lab = {
           storage = {
@@ -18,9 +70,7 @@
       atlas = {
         type = "physical";
         arch = "x86_64-linux";
-    isRaspberryPi = false;
         isHypervisor = true;
-    isVirtualMachine = false;
 
         nixosModule.lab = {
           storage = {
@@ -39,9 +89,7 @@
       jefke = {
         type = "physical";
         arch = "x86_64-linux";
-    isRaspberryPi = false;
         isHypervisor = true;
-    isVirtualMachine = false;
 
         nixosModule.lab = {
           storage = {
@@ -60,9 +108,7 @@
       lewis = {
         type = "physical";
         arch = "x86_64-linux";
-    isRaspberryPi = false;
         isHypervisor = true;
-    isVirtualMachine = false;
 
         nixosModule.lab = {
           backups.enable = true;
@@ -85,22 +131,22 @@
       hermes = {
         type = "virtual";
         hypervisorName = "lewis";
-    isRaspberryPi = false;
-    isVirtualMachine = true;
-    isHypervisor = false;
 
         nixosModule = { config, ... }: {
           lab = {
             networking = {
               dmz.services.enable = true;
               staticNetworking = true;
-          staticIPv4 = config.lab.networking.dmz.ipv4.services;
-          staticIPv6 = config.lab.networking.dmz.ipv6.services;
+              # TODO: This seems to cause infinite recursion? Really weird.
+              # staticIPv4 = config.lab.networking.dmz.ipv4.services;
+              # staticIPv6 = config.lab.networking.dmz.ipv6.services;
+              staticIPv4 = "192.168.30.7";
+              staticIPv6 = "2a0d:6e00:1a77:30::7";
             };
 
             vm = {
-          # TODO: would be cool to create a check that a mac address is only ever assigned to one VM.
-          # TODO: idea: what if we generated these IDs by hashing the host name and reducing that to the amount of hosts possible?
+              #     # TODO: would be cool to create a check that a mac address is only ever assigned to one VM.
+              #     # TODO: idea: what if we generated these IDs by hashing the host name and reducing that to the amount of hosts possible?
               id = 7;
 
               shares = [{
@@ -115,9 +161,6 @@
       maestro = {
         type = "virtual";
         hypervisorName = "atlas";
-    isRaspberryPi = false;
-    isVirtualMachine = false;
-    isHypervisor = false;
 
         nixosModule = { config, ... }: {
           microvm.balloonMem = 7680;
@@ -135,9 +178,6 @@
       bancomart = {
         type = "virtual";
         hypervisorName = "jefke";
-    isRaspberryPi = false;
-    isVirtualMachine = false;
-    isHypervisor = false;
 
         nixosModule = {
           microvm.balloonMem = 7680;
@@ -152,9 +192,6 @@
       vpay = {
         type = "virtual";
         hypervisorName = "lewis";
-    isRaspberryPi = false;
-    isVirtualMachine = false;
-    isHypervisor = false;
 
         nixosModule = {
           microvm.balloonMem = 5120;
@@ -165,4 +202,6 @@
           };
         };
       };
+    };
+  };
 }

nixos/modules/networking/default.nix

@@ -117,7 +117,7 @@ in {
             networkConfig.Bridge = cfg.dmz.bridgeName;
           };
         })
-        (lib.optionalAttrs machine.isVirtualMachine {
+        (lib.optionalAttrs (machine.type == "virtual") {
           "30-main-nic" = {
             matchConfig.Name = "en*";