metrics: Add metrics with victoriametrics + grafana

configuration/services/gitea.nix

@@ -1,6 +1,7 @@
 {
   pkgs,
   config,
+  lib,
   ...
 }: let
   domain = "gitea.${config.services.nginx.domain}";
@@ -19,11 +20,23 @@ in {
         SSH_PORT = 2222;
       };
 
+      metrics = {
+        ENABLED = true;
+        TOKEN = "#metricstoken#";
+      };
       service.DISABLE_REGISTRATION = true;
       session.COOKIE_SECURE = true;
     };
   };
 
+  systemd.services.gitea.serviceConfig.ExecStartPre = let
+    replaceSecretBin = "${pkgs.replace-secret}/bin/replace-secret";
+    secretPath = config.sops.secrets."gitea/metrics-token".path;
+    runConfig = "${config.services.gitea.customDir}/conf/app.ini";
+  in [
+    "+${replaceSecretBin} '#metricstoken#' '${secretPath}' '${runConfig}'"
+  ];
+
   # Set up SSL
   services.nginx.virtualHosts."${domain}" = let
     httpAddress = config.services.gitea.settings.server.HTTP_ADDR;
@@ -33,9 +46,18 @@ in {
     enableACME = true;
     extraConfig = ''
       add_header Strict-Transport-Security "max-age=15552000; includeSubDomains" always;
+      access_log /var/log/nginx/${domain}/access.log upstream_time;
     '';
 
     locations."/".proxyPass = "http://${httpAddress}:${toString httpPort}";
+    locations."/metrics" = {
+      extraConfig = ''
+        access_log off;
+        allow 127.0.0.1;
+        ${lib.optionalString config.networking.enableIPv6 "allow ::1;"}
+        deny all;
+      '';
+    };
   };
 
   # Block repeated failed login attempts