nixos/modules/services/postgresql.nix

inputs:
{
  options.nixos.services.postgresql = let inherit (inputs.lib) mkOption types; in
  {
    enable = mkOption { type = types.bool; default = false; };
    instances = mkOption
    {
      type = types.attrsOf (types.submodule (submoduleInputs: { options =
      {
        database = mkOption { type = types.nonEmptyStr; default = submoduleInputs.config._module.args.name; };
        user = mkOption { type = types.nonEmptyStr; default = submoduleInputs.config._module.args.name; };
        passwordFile = mkOption { type = types.nullOr types.nonEmptyStr; default = null; };
      };}));
      default = {};
    };
  };
  config =
    let
      inherit (inputs.config.nixos.services) postgresql;
      inherit (inputs.lib) mkMerge mkAfter concatStringsSep mkIf;
      inherit (inputs.localLib) stripeTabs attrsToList;
      inherit (builtins) map listToAttrs filter;
    in mkIf postgresql.enable
    {
      services =
      {
        postgresql =
        {
          enable = true;
          package = inputs.pkgs.postgresql_15;
          enableTCPIP = true;
          authentication = "host all all 0.0.0.0/0 md5";
          settings =
          {
            unix_socket_permissions = "0700";
            shared_buffers = "8192MB";
            work_mem = "512MB";
            autovacuum = "on";
          };
          # log_timezone = 'Asia/Shanghai'
          # datestyle = 'iso, mdy'
          # timezone = 'Asia/Shanghai'
          # lc_messages = 'en_US.utf8'
          # lc_monetary = 'en_US.utf8'
          # lc_numeric = 'en_US.utf8'
          # lc_time = 'en_US.utf8'
          # default_text_search_config = 'pg_catalog.english'
          # plperl.on_init = 'use utf8; use re; package utf8; require "utf8_heavy.pl";'
          # mv /path/to/dir /path/to/dir_old
          # mkdir /path/to/dir
          # chattr +C /path/to/dir
          # cp -a --reflink=never /path/to/dir_old/. /path/to/dir
          # rm -rf /path/to/dir_old
          ensureDatabases = map (db: db.value.database) (attrsToList postgresql.instances);
          ensureUsers = map (db: { name = db.value.user; }) (attrsToList postgresql.instances);
        };
        postgresqlBackup =
        {
          enable = true;
          pgdumpOptions = "-Fc";
          compression = "none";
          databases = map (db: db.value.database) (attrsToList postgresql.instances);
        };
      };
      systemd.services.postgresql.postStart = mkAfter (concatStringsSep "\n" (map
        (db:
          let
            passwordFile =
              if db.value.passwordFile or null != null then db.value.passwordFile
              else inputs.config.sops.secrets."postgresql/${db.value.user}".path;
            in
            # set user password
            "$PSQL -tAc \"ALTER USER ${db.value.user} with encrypted password '$(cat ${passwordFile})'\""
            # set db owner
              + "\n"
              + "$PSQL -tAc \"select pg_catalog.pg_get_userbyid(d.datdba) FROM pg_catalog.pg_database d"
              + " WHERE d.datname = '${db.value.database}' ORDER BY 1\""
              + " | grep -E '^${db.value.user}$' -q"
              + " || $PSQL -tAc \"ALTER DATABASE ${db.value.database} OWNER TO ${db.value.user}\"")
        (attrsToList postgresql.instances)));
      sops.secrets = listToAttrs (map
        (db: { name = "postgresql/${db.value.user}"; value.owner = inputs.config.users.users.postgres.name; })
        (filter (db: db.value.passwordFile == null) (attrsToList postgresql.instances)));
    };
}
  # sops.secrets.drone-agent = {
  #   owner = config.systemd.services.drone-agent.serviceConfig.User;
  #   key = "drone";
  # };
# pg_dump -h 127.0.0.1 -U synapse -Fc -f synaps.dump synapse
# pg_restore -h 127.0.0.1 -U misskey -d misskey --data-only --jobs=4 misskey.dump