etcnixos -> system

system/declarative-nm.nix

@@ -0,0 +1,51 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+# from: https://discourse.nixos.org/t/imperative-declarative-wifi-networks-with-wpa-supplicant/12394/6
+let
+  cfg = config.networking.networkmanager;
+
+  getFileName = lib.stringAsChars (x: if x == " " then "-" else x);
+
+  createWifi = ssid: opt: {
+    name = "NetworkManager/system-connections/${getFileName ssid}.nmconnection";
+    value = {
+      mode = "0400";
+      source = pkgs.writeText "${ssid}.nmconnection" ''
+        [connection]
+        id=${ssid}
+        type=wifi
+
+        [wifi]
+        ssid=${ssid}
+
+        [wifi-security]
+        ${lib.optionalString (opt.psk != null) ''
+          key-mgmt=wpa-psk
+          psk=${opt.psk}''}
+      '';
+    };
+  };
+
+  keyFiles = lib.mapAttrs' createWifi config.networking.wireless.networks;
+in
+{
+  config = lib.mkIf cfg.enable {
+    environment.etc = keyFiles;
+
+    systemd.services.NetworkManager-predefined-connections = {
+      restartTriggers = lib.mapAttrsToList (name: value: value.source) keyFiles;
+      serviceConfig = {
+        Type = "oneshot";
+        RemainAfterExit = true;
+        ExecStart = "${pkgs.coreutils}/bin/true";
+        ExecReload = "${pkgs.networkmanager}/bin/nmcli connection reload";
+      };
+      reloadIfChanged = true;
+      wantedBy = [ "multi-user.target" ];
+    };
+  };
+}