Enable metrics for matrix-synapse

config/hosts/metrics/nginx.nix

@@ -22,25 +22,6 @@
           proxyWebsockets = true;
         };
       };
-      "alertmanager.grzb.de"= {
-        forceSSL = true;
-        enableACME = true;
-        listen = [
-          {
-            addr = "0.0.0.0";
-            port = 80;
-          }
-          {
-            addr = "0.0.0.0";
-            port = 443;
-            ssl = true;
-          }
-        ];
-        locations."/" = {
-          proxyPass = "http://${config.services.prometheus.alertmanager.listenAddress}:${builtins.toString config.services.prometheus.alertmanager.port}";
-          proxyWebsockets = true;
-        };
-      };
     };
   };
 }

config/hosts/metrics/prometheus.nix

@@ -1,8 +1,16 @@
-{ hosts, ... }:
+{ hosts, pkgs, ... }:
+let
+  # https://github.com/element-hq/synapse/tree/master/contrib/prometheus/
+  synapseRules = pkgs.fetchurl {
+    url = "https://raw.githubusercontent.com/element-hq/synapse/refs/heads/master/contrib/prometheus/synapse-v2.rules";
+    hash = "sha256-WldlBdCMzul49OlFhJMsrx4MYFakHTa36Y9HnV22EwI=";
+  };
+in
 {
   services.prometheus = {
     enable = true;
     retentionTime = "90d";
+    ruleFiles = [ synapseRules ];
     scrapeConfigs = [
       {
         job_name = "node";
@@ -15,6 +23,14 @@
           };
         }) (builtins.attrNames hosts);
       }
+      {
+        job_name = "synapse";
+        scrape_interval = "15s";
+        metrics_path = "/_synapse/metrics";
+        static_configs = [{
+          targets = [ "matrix.vs.grzb.de:9000" ];
+        }];
+      }
     ];
   };
 }