nixos: add gatus service

From unstable.

nixos/flake.nix

@@ -33,6 +33,7 @@
           modules = [
             ({ config, pkgs, ... }: { nixpkgs.overlays = [ overlay-unstable ]; })
             ./hosts/chewbacca
+            (import "${nixpkgs-unstable}/nixos/modules/services/monitoring/gatus.nix")
             home-manager.nixosModules.home-manager
             {
               home-manager.useGlobalPkgs = true;

nixos/hosts/chewbacca/default.nix

@@ -4,6 +4,7 @@
   imports =
     [
       ./hardware-configuration.nix
+      ./../../services/gatus.nix
       ./../../services/glances.nix
       ./../../services/jellyfin.nix
       ./../../services/music-assistant.nix

nixos/services/gatus.nix

@@ -0,0 +1,30 @@
+{ config, pkgs, ... }:
+
+let
+  tailscaleDevices = [
+    { hostname = "chewbacca"; address = "100.110.122.14"; }
+    { hostname = "luffy"; address = "100.118.93.10"; }
+  ];
+in
+{
+  services.gatus = {
+    enable = true;
+    openFirewall = true;
+    settings = {
+      endpoints = map
+        (device:
+          {
+            name = device.hostname;
+            url = "icmp://${device.address}";
+            interval = "5m";
+            conditions = [
+              "[CONNECTED] == true"
+            ];
+          }
+        )
+        tailscaleDevices;
+    };
+  };
+
+  systemd.services.gatus.serviceConfig.AmbientCapabilities = "CAP_NET_RAW";
+}

nixos/services/traefik/dynamic.yaml

@@ -36,6 +36,10 @@ http:
         - adminprefix
       service: pihole
 
+    gatus:
+      rule: "Host(`gatus.hallstrom.duckdns.org`)"
+      service: gatus
+
   middlewares:
     sslheader:
       headers:
@@ -81,3 +85,8 @@ http:
       loadBalancer:
         servers:
           - url: "http://192.168.1.24"
+
+    gatus:
+      loadBalancer:
+        servers:
+          - url: "http://192.168.1.49:8080"