monitoring: added services

machines/gerd/services/monitoring/mon-postgres.nix

@@ -0,0 +1,34 @@
+{ config, pkgs, ... }:
+
+{
+  services.prometheus.exporters.postgres = {
+    enable = true;
+    listenAddress = "localhost";
+    runAsLocalSuperUser = true;
+
+    extraFlags = let
+      extraQuery = pkgs.writeText "prometehus-postgres-query.yaml" ''
+        pg_database:
+          query: "SELECT pg_database.datname, pg_database_size(pg_database.datname) as size FROM pg_database"
+          metrics:
+            - datname:
+                usage: "LABEL"
+                description: "Name of the database"
+            - size:
+                usage: "GAUGE"
+                description: "Disk space used by the database"
+      '';
+    in [
+      "--extend.query-path=${extraQuery}"
+    ];
+  };
+  
+  services.prometheus.scrapeConfigs = [
+    {
+      job_name = "postgres";
+      static_configs = [{
+        targets = [ "localhost:${toString config.services.prometheus.exporters.postgres.port}" ];
+      }];
+    }
+  ];
+}