Postgresql inside nix-shell

shell.nix

with import <nixpkgs> {};

stdenv.mkDerivation {
    name = "postgresql-inside-nixshell";

    buildInputs = [
        postgresql
    ];

    shellHook = ''
        export PGDATA=$(mktemp -d)
        export SOCKET_DIRECTORIES=$(mktemp -d)

        initdb
        echo "unix_socket_directories = '$SOCKET_DIRECTORIES'" >> $PGDATA/postgresql.conf
        pg_ctl -l $PGDATA/logfile start

        function end {
          echo "Shutting down the database..."
          pg_ctl stop

          echo "Removing directories..."
          rm -rf $PGDATAA $SOCKET_DIRECTORIES
        }

        trap end EXIT
    '';
}