perf: allow caching wireguard network information to significantly speed up evaluation

lib/wireguard.nix

@@ -16,6 +16,7 @@ inputs: final: prev: let
     nameValuePair
     partition
     removeSuffix
+    warn
     ;
 
   inherit
@@ -32,8 +33,8 @@ inputs: final: prev: let
 in {
   lib =
     prev.lib
-    // {
+    // rec {
-      wireguard = userInputs: wgName: let
+      wireguard.evaluateNetwork = userInputs: wgName: let
         inherit (userInputs.self) nodes;
         # Returns the given node's wireguard configuration of this network
         wgCfgOf = node: nodes.${node}.config.wireguard.${wgName};
@@ -220,5 +221,24 @@ in {
           wgQuickConfigScript
           ;
       };
+
+      wireguard.createEvalCache = userInputs: wgNames:
+        genAttrs wgNames (wireguard.evaluateNetwork userInputs);
+
+      wireguard.getNetwork = userInputs: wgName:
+        userInputs.self.wireguardEvalCache.${wgName}
+        or (
+          warn ''
+            The calculated information for the wireguard network "${wgName}" is not cached!
+            This will siginificantly increase evaluation times. Please consider pre-evaluating
+            this information by exposing it in your flake:
+
+              wireguardEvalCache.${wgName} = lib.wireguard.createEvalCache inputs [
+                "${wgName}"
+                # all other networks
+              ];
+
+          '' (wireguard.evaluateNetwork userInputs wgName)
+        );
     };
 }

modules/topology-wireguard.nix

@@ -30,7 +30,7 @@ in {
     topology.networks = mkMerge (
       flip mapAttrsToList config.wireguard (
         wgName: _: let
-          inherit (lib.wireguard inputs wgName) networkCidrs;
+          inherit (lib.wireguard.getNetwork inputs wgName) networkCidrs;
         in {
           ${networkId wgName} = {
             name = mkDefault "Wireguard network '${wgName}'";
@@ -47,7 +47,7 @@ in {
       flip mapAttrsToList config.wireguard (
         wgName: wgCfg: let
           inherit
-            (lib.wireguard inputs wgName)
+            (lib.wireguard.getNetwork inputs wgName)
             participatingServerNodes
             wgCfgOf
             ;

modules/wireguard.nix

@@ -28,7 +28,6 @@
     optionals
     stringLength
     types
-    wireguard
     ;
 
   cfg = config.wireguard;
@@ -36,7 +35,7 @@
 
   configForNetwork = wgName: wgCfg: let
     inherit
-      (wireguard inputs wgName)
+      (lib.wireguard.getNetwork inputs wgName)
       externalPeerName
       externalPeerNamesRaw
       networkCidrs
@@ -385,7 +384,7 @@ in {
 
         ipv4 = mkOption {
           type = types.lazyOf types.net.ipv4;
-          default = types.lazyValue (wireguard inputs name).assignedIpv4Addresses.${nodeName};
+          default = types.lazyValue (lib.wireguard.getNetwork inputs name).assignedIpv4Addresses.${nodeName};
           description = ''
             The ipv4 address for this machine. If you do not set this explicitly,
             a semi-stable ipv4 address will be derived automatically based on the
@@ -397,7 +396,7 @@ in {
 
         ipv6 = mkOption {
           type = types.lazyOf types.net.ipv6;
-          default = types.lazyValue (wireguard inputs name).assignedIpv6Addresses.${nodeName};
+          default = types.lazyValue (lib.wireguard.getNetwork inputs name).assignedIpv6Addresses.${nodeName};
           description = ''
             The ipv6 address for this machine. If you do not set this explicitly,
             a semi-stable ipv6 address will be derived automatically based on the