nixos/prometheus: init pihole-exporter

nixos/modules/services/monitoring/prometheus/exporters.nix

@@ -48,6 +48,7 @@ let
     "node"
     "openldap"
     "openvpn"
+    "pihole"
     "postfix"
     "postgres"
     "py-air-control"

nixos/modules/services/monitoring/prometheus/exporters/pihole.nix

@@ -0,0 +1,74 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.pihole;
+in
+{
+  port = 9617;
+  extraOpts = {
+    apiToken = mkOption {
+      type = types.str;
+      default = "";
+      example = "580a770cb40511eb85290242ac130003580a770cb40511eb85290242ac130003";
+      description = ''
+        pi-hole API token which can be used instead of a password
+      '';
+    };
+    interval = mkOption {
+      type = types.str;
+      default = "10s";
+      example = "30s";
+      description = ''
+        How often to scrape new data
+      '';
+    };
+    password = mkOption {
+      type = types.str;
+      default = "";
+      example = "password";
+      description = ''
+        The password to login into pihole. An api token can be used instead.
+      '';
+    };
+    piholeHostname = mkOption {
+      type = types.str;
+      default = "pihole";
+      example = "127.0.0.1";
+      description = ''
+        Hostname or address where to find the pihole webinterface
+      '';
+    };
+    piholePort = mkOption {
+      type = types.port;
+      default = "80";
+      example = "443";
+      description = ''
+        The port pihole webinterface is reachable on
+      '';
+    };
+    protocol = mkOption {
+      type = types.enum [ "http" "https" ];
+      default = "http";
+      example = "https";
+      description = ''
+        The protocol which is used to connect to pihole
+      '';
+    };
+  };
+  serviceOpts = {
+    serviceConfig = {
+      ExecStart = ''
+        ${pkgs.bash}/bin/bash -c "${pkgs.prometheus-pihole-exporter}/bin/pihole-exporter \
+          -interval ${cfg.interval} \
+          ${optionalString (cfg.apiToken != "") "-pihole_api_token ${cfg.apiToken}"} \
+          -pihole_hostname ${cfg.piholeHostname} \
+          ${optionalString (cfg.password != "") "-pihole_password ${cfg.password}"} \
+          -pihole_port ${toString cfg.piholePort} \
+          -pihole_protocol ${cfg.protocol} \
+          -port ${toString cfg.port}"
+      '';
+    };
+  };
+}