infrastructure/modules/nixos/dgn-monitoring/exporters.nix

# SPDX-FileCopyrightText: 2024 Maurice Debray <maurice.debray@dgnum.eu>
# SPDX-FileCopyrightText: 2024 Ryan Lahfa <ryan.lahfa@dgnum.eu>
#
# SPDX-License-Identifier: EUPL-1.2

{
  pkgs,
  sources,
  config,
  lib,
  ...
}:
let
  inherit (lib)
    optional
    mapAttrs
    mapAttrs'
    mkDefault
    mkIf
    mkOption
    nameValuePair
    recursiveUpdate
    ;

  inherit (lib.types) attrsOf bool port;

  cfg = config.dgn-monitoring.exporters;
in

{
  options.dgn-monitoring.exporters = {
    enable = mkOption {
      type = bool;
      default = config.dgn-monitoring.enable;
      description = ''
        Whether to enable standard exporters for the dgnum monitoring system.
      '';
    };

    ports = mkOption {
      type = attrsOf port;
      description = ''
        Ports to listen on for each exporter.
      '';
    };
  };

  imports = [ "${sources.cgroup-exporter}/nix/module.nix" ];

  config = mkIf cfg.enable {
    dgn-monitoring.exporters.ports = mapAttrs (_: mkDefault) {
      node = 9002;
      cgroup = 9003;
    };

    services.prometheus = {
      exporters =
        recursiveUpdate
          {
            node = {
              enable = true;
              enabledCollectors = [
                "processes"
                "systemd"
              ] ++ (optional config.boot.zfs.enabled "zfs");
            };

            cgroup = {
              enable = true;
              package = pkgs.callPackage "${sources.cgroup-exporter}/nix/package.nix" { };
            };
          }
          (
            mapAttrs (_: port: {
              inherit port;
              # NOTE: We always listen on localhost, as the agent runs on the same machine
              listenAddress = "127.0.0.1";
            }) cfg.ports
          );
    };

    dgn-web.internalPorts = mapAttrs' (name: nameValuePair "${name}-exporter") cfg.ports;
  };
}