nichts/modules/services/prometheus/prometheus.mod.nix

{
  config,
  lib,
  pkgs,
  ...
}:
let
  inherit (lib.modules) mkIf;
  inherit (lib.options) mkEnableOption;

  cfg = config.modules.system.services.prometheus;
  port = 4022;
in
{
  options.modules.system.services.prometheus.enable = mkEnableOption "Grafana, a graphing service";

  config = mkIf cfg.enable {
    services.prometheus = {
      enable = true;
      package = pkgs.prometheus;
      inherit port;

      exporters = {
        node = {
          enable = true;
          port = 4023;
          enabledCollectors = [
            "systemd"
            "processes"
          ];
        };

        postgres = {
          enable = true;
          port = 4024;
          user = "postgres";
        };
        nginx = {
          enable = true;
          port = 4025;
        };
      };
      scrapeConfigs = [
        {
          job_name = "prometheus";
          scrape_interval = "30s";
          static_configs = [ { targets = [ "localhost:${toString port}" ]; } ];
        }
        {
          job_name = "node";
          scrape_interval = "30s";
          static_configs = [
            { targets = [ "localhost:${toString config.services.prometheus.exporters.node.port}" ]; }
          ];
        }
        {
          job_name = "postgres";
          scrape_interval = "30s";
          static_configs = [
            { targets = [ "localhost:${toString config.services.prometheus.exporters.postgres.port}" ]; }
          ];
        }
        {
          job_name = "nginx";
          scrape_interval = "30s";
          static_configs = [
            { targets = [ "localhost:${toString config.services.prometheus.exporters.nginx.port}" ]; }
          ];
        }
      ];
    };
  };
}