pvv-nixos-config/hosts/ildkule/services/monitoring/prometheus/dibbler.nix

{
  config,
  lib,
  pkgs,
  ...
}:
let
  cfg = config.services.prometheus.exporters.sql;
  configFile =
    if cfg.configFile != null then
      cfg.configFile
    else
      let
        nameInline = lib.mapAttrsToList (k: v: v // { name = k; });
        renameStartupSql = j: removeAttrs (j // { startup_sql = j.startupSql; }) [ "startupSql" ];
        configuration = {
          jobs = map renameStartupSql (
            nameInline (lib.mapAttrs (k: v: (v // { queries = nameInline v.queries; })) cfg.configuration.jobs)
          );
        };
      in
      builtins.toFile "config.yaml" (builtins.toJSON configuration);
in
{
  sops.secrets."config/postgresql_dibbler_password" = { };

  services.prometheus.scrapeConfigs = [
    {
      job_name = "sql_exporter";
      scrape_interval = "1m";
      scheme = "http";

      static_configs = [
        {
          targets = [ "localhost:9237" ];
        }
      ];
    }
  ];

  services.prometheus.exporters.sql = {
    enable = true;
    configuration = {
      jobs.dibbler = {
        interval = "1m";

        queries."daily_purchase_sum" = {
          help = "Sum of purchases for the current day.";
          labels = [ "thing" ];
          values = [ "sum" ];
          query = "SELECT SUM(price) FROM purchases GROUP BY DATE(time) ORDER BY DATE(time) DESC LIMIT 1";
        };

        queries."total_purchase_sum" = {
          help = "Sum of all purchases.";
          labels = [ "thing" ];
          values = [ "sum" ];
          query = "SELECT SUM(price) FROM purchases";
        };

        queries."total_stock_value" = {
          help = "The value of all stock in dibbler.";
          labels = [ "thing" ];
          values = [ "sum" ];
          query = "SELECT SUM(price * stock) FROM products";
        };

        queries."user_credit_sum" = {
          help = "The sum of all user credit.";
          labels = [ "thing" ];
          values = [ "sum" ];
          query = "SELECT SUM(credit) FROM users";
        };
      };
    };
  };

  systemd.services."prometheus-sql-exporter".serviceConfig = {
    RuntimeDirectory = "prometheus-sql-exporter";
    LoadCredential = "postgresql_dibbler_password:${
      config.sops.secrets."config/postgresql_dibbler_password".path
    }";
    ExecStartPre = ''/bin/sh -c '${lib.getExe' pkgs.coreutils "cat"} ${configFile} | ${lib.getExe' pkgs.jq "jq"} -c \".jobs[0].connections[0]=\\\"postgres://pvv_vv:$(${lib.getExe' pkgs.coreutils "cat"} %d/postgresql_dibbler_password)@postgres.pvv.ntnu.no\\\"\" > /run/prometheus-sql-exporter/config.yaml' '';
    ExecStart = lib.mkForce ''
      ${pkgs.prometheus-sql-exporter}/bin/sql_exporter \
        -web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
        -config.file /run/prometheus-sql-exporter/config.yaml \
        ${lib.concatStringsSep " \\\n  " cfg.extraFlags}
    '';
  };
}