fail2ban: Add metrics

configuration/services/fail2ban.nix

@@ -0,0 +1,42 @@
+{pkgs, ...}: {
+  services.fail2ban = {
+    enable = true;
+    extraPackages = [pkgs.ipset];
+    banaction = "iptables-ipset-proto6-allports";
+    bantime-increment.enable = true;
+
+    jails = {
+      nginx-botsearch = ''
+        enabled = true
+        logpath = /var/log/nginx/access.log
+      '';
+    };
+
+    ignoreIP = [
+      "127.0.0.0/8"
+      "10.0.0.0/8"
+      "172.16.0.0/12"
+      "192.168.0.0/16"
+    ];
+  };
+
+  # Allow metrics services to connect to the socket as well
+  users.groups.fail2ban = {};
+  systemd.services.fail2ban.serviceConfig = {
+    ExecStartPost =
+      "+"
+      + (pkgs.writeShellScript "fail2ban-post-start" ''
+        while ! [ -S /var/run/fail2ban/fail2ban.sock ]; do
+            sleep 1
+        done
+
+        while ! ${pkgs.netcat}/bin/nc -zU /var/run/fail2ban/fail2ban.sock; do
+            sleep 1
+        done
+
+        ${pkgs.coreutils}/bin/chown root:fail2ban /var/run/fail2ban /var/run/fail2ban/fail2ban.sock
+        ${pkgs.coreutils}/bin/chmod 660 /var/run/fail2ban/fail2ban.sock
+        ${pkgs.coreutils}/bin/chmod 710 /var/run/fail2ban
+      '');
+  };
+}