feat: add prometheus config

config/services.nix

@@ -11,4 +11,20 @@ rec {
       "processes"
     ];
   };
+
+  prometheus = {
+    port = 9090;
+    scrapeConfigs = {
+      node = {
+        static_configs = [
+          {
+            targets = [ 
+              "localhost:9100"
+              "pi.home:9100"
+            ];
+          }
+        ];
+      };
+    };
+  };
 }

services/prometheus.nix

@@ -0,0 +1,20 @@
+{lib, ...}:
+let 
+  serv = import ../config/services.nix;
+  conf = lib.attrsets.mapAttrsToList (name: cfg: {
+    job_name = name;
+
+    static_configs = cfg.static_configs;
+  }) serv.prometheus.scrape_configs;
+in
+{
+  services.prometheus = {
+    enable = true;
+
+    scrapeConfigs = conf;
+
+    port = serv.prometheus.port;
+  };
+
+  networking.firewall.allowedTCPPorts = [ serv.prometheus.port ];
+}