initial refactoring

platforms/nixos/modules/services/identity.nix

@@ -0,0 +1,37 @@
+{ config, lib, ... }:
+
+let
+  cfg = config.services.wait-for-identity;
+in
+{
+
+  options.services.wait-for-identity = {
+    enable = lib.mkEnableOption "Wait for identity file oneshot";
+    identityFile = lib.mkOption {
+      type = lib.types.path;
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+
+    # Wait for secret to be placed on the machine
+    systemd.services.wait-for-identity = {
+      description = "Wait until identity file exists on the machine";
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        Type = "oneshot";
+        RemainAfterExit = true;
+      };
+      script = ''
+        for i in $(seq 1 10); do
+            if [ -f ${builtins.toString cfg.identityFile} ]; then
+                echo "Identity file found."
+                exit 0
+            fi
+            sleep 6
+        done
+      '';
+    };
+
+  };
+}