hosts/monitoring-3: add synapse monitoring

hosts/monitoring-3/blackbox.nix

@@ -0,0 +1,30 @@
+{ pkgs, ... }:
+
+{
+  services.prometheus.exporters.blackbox = {
+    enable = true;
+    openFirewall = true;
+    configFile = pkgs.writeText "blackbox.yml" ''
+      modules:
+        icmp6:
+          prober: icmp
+          icmp:
+            preferred_ip_protocol: ip6
+            ip_protocol_fallback: false
+        icmp4:
+          prober: icmp
+          icmp:
+            preferred_ip_protocol: ip4
+            ip_protocol_fallback: false
+        synapse:
+          prober: http
+          http:
+            valid_status_codes:
+              - 200
+            method: GET
+            fail_if_not_ssl: true
+            fail_if_body_not_matches_regexp:
+              - "Synapse is running"
+    '';
+  };
+}

hosts/monitoring-3/configuration.nix

@@ -6,6 +6,7 @@
       ./hardware-configuration.nix
       ../../configuration/proxmox-vm
       ./alertmanager.nix
+      ./blackbox.nix
       ./grafana.nix
       ./nixos-validator.nix
       ./prometheus.nix

hosts/monitoring-3/prometheus.nix

@@ -263,6 +263,36 @@ in {
           relabelAddressToInstance
         ];
       }
+      {
+        job_name = "blackbox_local_synapse";
+        scrape_interval = "20s";
+        metrics_path = "/probe";
+        params = {
+          module = [ "synapse" ];
+        };
+        static_configs = [
+          {
+            targets = [
+              "https://matrix.entr0py.de/_matrix/static/"
+            ];
+          }
+        ];
+        relabel_configs = [
+          {
+            source_labels = [ "__address__" ];
+            target_label = "__param_target";
+          }
+          {
+            source_labels = [ "__param_target" ];
+            target_label = "target";
+          }
+          {
+            target_label = "__address__";
+            replacement = "monitoring-3.mon.clerie.de:9115";
+          }
+          relabelAddressToInstance
+        ];
+      }
       {
         job_name = "zimmer-temp";
         scrape_interval = "20s";