feat(systemdNotify): limit to one invocation every 15 minutes per service

Also adds an `ExecCondition` for ignoring service auto-resarts.

modules/systemdNotify.nix

@@ -26,6 +26,16 @@ let
     $(systemctl status --full "$1")
     ERRMAIL
   '';
+
+  checkConditions = pkgs.writeScript "check-conditions" ''
+    #!/bin/sh
+    STATUS=$(systemctl status --full "$1")
+
+    case "$STATUS" in
+      *"activating (auto-restart) (Result: timeout)"*) exit 1 ;;
+      *) exit 0 ;;
+    esac
+  '';
 in
 {
   options = {
@@ -85,10 +95,21 @@ in
       }
     ];
 
-    systemd.services."notify@" = {
+    systemd.services."notify@" =
+      lib.recursiveUpdate
+        {
           onFailure = lib.mkForce [ ];
+          unitConfig = {
+            StartLimitIntervalSec = "15m";
+            StartLimitBurst = 1;
+          };
+          serviceConfig = {
+            Type = "oneshot";
+            ExecCondition = "${checkConditions} %i";
+          };
         }
-    // optionalAttrs (cfg.method == "libnotify") {
+        (
+          optionalAttrs (cfg.method == "libnotify") {
             description = "Desktop notifications for %i service failure";
             environment = {
               DISPLAY = ":0";
@@ -100,17 +121,12 @@ in
                 "Service '$INSTANCE' failed" \
                 "$(journalctl -n 6 -o cat -u $INSTANCE)"
             '';
-      serviceConfig = {
-        Type = "oneshot";
-        User = cfg.libnotify.user;
-      };
+            serviceConfig.User = cfg.libnotify.user;
           }
           // optionalAttrs (cfg.method == "email") {
             description = "E-Mail notifications for %i service failure";
-      serviceConfig = {
-        ExecStart = "${sendmail} %i";
-        Type = "oneshot";
-      };
-    };
+            serviceConfig.ExecStart = "${sendmail} %i";
+          }
+        );
   };
 }