feat: init openwrt-prometheus-exporter module

Signed-off-by: soyouzpanda <soyouzpanda@soyouzpanda.fr>

modules/all-modules.nix

@@ -20,6 +20,7 @@
    ./mount
    ./network
    ./ntp
+   ./openwrt-prometheus-exporter
    ./outputs.nix
    ./outputs/ext4fs.nix
    ./outputs/initramfs.nix

modules/openwrt-prometheus-exporter/default.nix

@@ -0,0 +1,25 @@
+{ lib, pkgs, config, ... }:
+let
+  inherit (lib) mkOption types;
+  inherit (pkgs) liminix;
+in {
+  options = {
+    system.service.openwrt-prometheus-exporter = mkOption {
+      type = liminix.lib.types.serviceDefn;
+    };
+  };
+
+  config = {
+    system.service.openwrt-prometheus-exporter = liminix.callService ./service.nix {
+      httpPorts = mkOption {
+        type = types.listOf types.port;
+        default = [ ];
+      };
+
+      httpsPorts = mkOption {
+        type = types.listOf types.port;
+        default = [ ];
+      };
+    };
+  };
+}

modules/openwrt-prometheus-exporter/service.nix

@@ -0,0 +1,41 @@
+{
+  liminix,
+  lib,
+  lua,
+  luasocket,
+  uhttpd,
+  ubus,
+  openwrt-prometheus-exporter,
+  luabit,
+}:
+{ httpPorts, httpsPorts }:
+let
+  inherit (liminix.services) longrun;
+
+  mkLuaPath = package: "${package}/share/lua/${lua.luaversion}/?.lua";
+  mkLuaCPath = package: "${package}/lib/lua/${lua.luaversion}/?.so";
+
+  luaPath = lib.concatStringsSep ";" [
+    "$LUA_PATH"
+    (mkLuaPath openwrt-prometheus-exporter)
+    (mkLuaPath luasocket)
+  ];
+
+  luaCPath = lib.concatStringsSep ";" [
+    "$LUA_CPATH"
+    (mkLuaCPath luasocket)
+    (mkLuaCPath ubus)
+    (mkLuaCPath luabit)
+  ];
+in longrun {
+  name = "openwrt-prometheus-exporter";
+  run = ''
+    export LD_LIBRARY_PATH=${uhttpd}/lib/:$LD_LIBRARY_PATH
+    export LUA_CPATH="${luaCPath}"
+    export LUA_PATH="${luaPath}"
+
+    ${uhttpd}/bin/uhttpd -f -c /dev/null -l / -L ${openwrt-prometheus-exporter}/bin/openwrt-prometheus-exporter \
+      ${lib.concatStringsSep " " (lib.map (port: "-p ${toString port}") httpPorts)} \
+      ${lib.concatStringsSep " " (lib.map (port: "-s ${toString port}") httpsPorts)}
+  '';
+}