Add postgres exporter

services/monitoring/exporters/default.nix

@@ -10,6 +10,7 @@ in
   imports = [
     ./baseline.nix
     ./nginx.nix
+    ./postgres.nix
   ];
 
   options.bagel = {

services/monitoring/exporters/postgres.nix

@@ -0,0 +1,31 @@
+{
+  config,
+  lib,
+  ...
+}:
+let
+  cfg = config.bagel.monitoring.exporters.postgres;
+  inherit (lib) mkEnableOption mkIf;
+in
+{
+  options.bagel.monitoring.exporters.postgres.enable = (mkEnableOption "Postgres exporter") // { default = config.services.postgresql.enable; };
+
+  config = mkIf cfg.enable {
+    services.prometheus.exporters.postgres = {
+      enable = true;
+      port = 9104;
+      runAsLocalSuperUser = true;
+      extraFlags = [
+        "--collector.long_running_transactions"
+        "--collector.stat_activity_autovacuum"
+        "--collector.stat_statements"
+      ];
+    };
+
+    services.postgresql.settings.shared_preload_libraries = "pg_stat_statements";
+
+    bagel.meta.monitoring.exporters = [
+      { port = 9104; }
+    ];
+  };
+}