path: root/systems/eldiron/databases/mariadb.nix

{ lib, pkgs, config, ... }:
let
    cfg = config.myServices.databases.mariadb;
in {
  options.myServices.databases = {
    mariadb = {
      enable = lib.mkOption {
        default = false;
        example = true;
        description = "Whether to enable mariadb database";
        type = lib.types.bool;
      };
      package = lib.mkOption {
        type = lib.types.package;
        default = pkgs.mariadb;
        description = ''
          Mariadb package to use.
          '';
      };
      credentials = lib.mkOption {
        default = {};
        description = "Credentials";
        type = lib.types.attrsOf lib.types.str;
      };
      ldapConfig = lib.mkOption {
        description = "LDAP configuration to allow PAM identification via LDAP";
        type = lib.types.submodule {
          options = {
            host = lib.mkOption { type = lib.types.str; };
            base = lib.mkOption { type = lib.types.str; };
            dn = lib.mkOption { type = lib.types.str; };
            password = lib.mkOption { type = lib.types.str; };
            filter = lib.mkOption { type = lib.types.str; };
          };
        };
      };
      replicationLdapConfig = lib.mkOption {
        description = "LDAP configuration to allow replication";
        type = lib.types.submodule {
          options = {
            host = lib.mkOption { type = lib.types.str; };
            base = lib.mkOption { type = lib.types.str; };
            dn = lib.mkOption { type = lib.types.str; };
            password = lib.mkOption { type = lib.types.str; };
          };
        };
      };
      dataDir = lib.mkOption {
        type = lib.types.path;
        default = "/var/lib/mysql";
        description = ''
          The directory where Mariadb stores its data.
        '';
      };
      # Output variables
      socketsDir = lib.mkOption {
        type = lib.types.path;
        default = "/run/mysqld";
        description = ''
          The directory where Mariadb puts sockets.
          '';
      };
      sockets = lib.mkOption {
        type = lib.types.attrsOf lib.types.path;
        default = {
          mysqld  = "${cfg.socketsDir}/mysqld.sock";
        };
        readOnly = true;
        description = ''
          Mariadb sockets
          '';
      };
    };
  };

  config = lib.mkIf cfg.enable {
    networking.firewall.allowedTCPPorts = [ config.myEnv.databases.mysql.port ];

    # 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';

    # To create a user (host) for replication:
    # CREATE USER 'host'@'%' IDENTIFIED VIA pam USING 'mysql_replication' REQUIRE SSL;
    # GRANT REPLICATION SLAVE, REPLICATION CLIENT, RELOAD, LOCK TABLES, SELECT, SHOW VIEW ON *.* TO 'host'@'%';
    # (the lock/select grant permits to let the replication host handle
    # the initial fetch of the database)
    # % should be valid for both localhost (for cron dumps) and the origin host.
    services.mysql = {
      enable = true;
      package = cfg.package;
      dataDir = cfg.dataDir;
      settings = {
        mysqld = {
          port = config.myEnv.databases.mysql.port;
          ssl_ca = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
          ssl_key = "${config.security.acme.certs.mysql.directory}/key.pem";
          ssl_cert = "${config.security.acme.certs.mysql.directory}/fullchain.pem";

          # for replication
          log-bin = "mariadb-bin";
          server-id = "1";

          # this introduces a small delay before storing on disk, but
          # makes it order of magnitudes quicker
          innodb_flush_log_at_trx_commit = "0";

          # This is necessary since the default ("dialog") is not
          # supported by php's mysqlnd plugin (in mysqli). But with that
          # change only regular login+password schemes can work (no
          # "fancy" authentication methods like fprintd or keys)
          pam_use_cleartext_plugin = true;
        };
      };
    };

    users.users.mysql.extraGroups = [ "keys" ];
    security.acme.certs."mysql" = {
      group = "mysql";
      domain = "db-1.immae.eu";
      postRun = ''
        systemctl restart mysql.service
      '';
    };

    secrets.keys = {
      "mysql/mysqldump" = {
        permissions = "0400";
        user = "root";
        group = "root";
        text = ''
          [mysqldump]
          user = root
          password = ${cfg.credentials.root}
        '';
      };
      "mysql/pam" = {
        permissions = "0400";
        user = "mysql";
        group = "mysql";
        text =  with cfg.ldapConfig; ''
          host ${host}
          base ${base}
          binddn ${dn}
          bindpw ${password}
          pam_filter ${filter}
          ssl start_tls
        '';
      };
      "mysql/pam_replication" = {
        permissions = "0400";
        user = "mysql";
        group = "mysql";
        text =  with cfg.replicationLdapConfig; ''
          host ${host}
          base ${base}
          binddn ${dn}
          bindpw ${password}
          pam_login_attribute cn
          ssl start_tls
        '';
      };
    };

    security.pam.services = let
      pam_ldap = "${pkgs.pam_ldap}/lib/security/pam_ldap.so";
    in {
      mysql = {
        text = ''
          # https://mariadb.com/kb/en/mariadb/pam-authentication-plugin/
          auth    required ${pam_ldap} config=${config.secrets.fullPaths."mysql/pam"}
          account required ${pam_ldap} config=${config.secrets.fullPaths."mysql/pam"}
          '';
      };
      mysql_replication = {
        text = ''
          auth    required ${pam_ldap} config=${config.secrets.fullPaths."mysql/pam_replication"}
          account required ${pam_ldap} config=${config.secrets.fullPaths."mysql/pam_replication"}
          '';
      };
    };

  };
}