totoro: add valveindexinstock

ops/nixos/totoro/default.nix

@@ -200,6 +200,22 @@ in {
 
     pushgateway.enable = true;
 
+    rules = [
+      ''
+        groups:
+        - name: valve_index
+          rules:
+          - alert: ValveIndexInStock
+            expr: valve_index_in_stock == 0
+            for: 1s
+            labels:
+              severity: page
+            annotations:
+              summary: "Valve Index in Stock!"
+              description: "The Valve Index is back in stock."
+      ''
+    ];
+
     alertmanager = {
       enable = true;
       configuration = {
@@ -265,5 +281,20 @@ in {
     };
   };
 
+  systemd.services.valveindexinstock = {
+    enable = true;
+    serviceConfig = {
+      ExecStart = "${depot.py.valveindexinstock}/bin/valveindexinstock";
+      DynamicUser = true;
+      MountAPIVFS = true;
+      PrivateTmp = true;
+      PrivateUsers = true;
+      ProtectControlGroups = true;
+      ProtectKernelModules = true;
+      ProtectKernelTunables = true;
+    };
+  };
+  my.prometheus.additionalExporterPorts.valveindexinstock = 9998;
+
   system.stateVersion = "20.03";
 }