{ lib, pkgs, config, myconfig, mylibs, ... }:
let
    cfg = config.services.myDatabases;
in {
  options.services.myDatabases = {
    mariadb = {
      enable = lib.mkOption {
        default = cfg.enable;
        example = true;
        description = "Whether to enable mariadb database";
        type = lib.types.bool;
      };
    };
  };

  config = lib.mkIf cfg.enable {
    nixpkgs.config.packageOverrides = oldpkgs: rec {
      mariadb = mariadbPAM;
      mariadbPAM = oldpkgs.mariadb.overrideAttrs(old: rec {
        cmakeFlags = old.cmakeFlags ++ [ "-DWITH_AUTHENTICATION_PAM=ON" ];
        buildInputs = old.buildInputs ++ [ pkgs.pam ];
      });
    };

    networking.firewall.allowedTCPPorts = [ 3306 ];

    # for adminer, ssl is implemented with mysqli only, which is
    # currently disabled because it’s not compatible with pam.
    # Thus we need to generate two users for each 'remote': one remote
    # with SSL, and one localhost without SSL.
    # User identified by LDAP:
    # CREATE USER foo@% IDENTIFIED VIA pam USING 'mysql' REQUIRE SSL;
    # CREATE USER foo@localhost IDENTIFIED VIA pam USING 'mysql';
    services.mysql = rec {
      enable = cfg.mariadb.enable;
      package = pkgs.mariadb;
      extraOptions = ''
        ssl_ca = ${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt
        ssl_key = /var/lib/acme/mysql/key.pem
        ssl_cert = /var/lib/acme/mysql/fullchain.pem
        '';
    };

    security.acme.certs."mysql" = config.services.myCertificates.certConfig // {
      user = "mysql";
      group = "mysql";
      plugins = [ "fullchain.pem" "key.pem" "account_key.json" ];
      domain = "db-1.immae.eu";
      postRun = ''
        systemctl restart mysql.service
      '';
    };

    security.pam.services = let
      pam_ldap = "${pkgs.pam_ldap}/lib/security/pam_ldap.so";
      pam_ldap_mysql = with myconfig.env.databases.mysql.pam;
        pkgs.writeText "mysql.conf" ''
        host ${myconfig.env.ldap.host}
        base ${myconfig.env.ldap.base}
        binddn ${dn}
        bindpw ${password}
        pam_filter ${filter}
        ssl start_tls
        '';
    in [
      {
        name = "mysql";
        text = ''
          # https://mariadb.com/kb/en/mariadb/pam-authentication-plugin/
          auth    required ${pam_ldap} config=${pam_ldap_mysql}
          account required ${pam_ldap} config=${pam_ldap_mysql}
          '';
      }
    ];

  };
}