use MongoDB;
my $database_server ="<IP>";
my $database_port = "<port>";
my $username = "<username>";
my $password = "<password>";
my $database_name = "<database>";
my $conn = MongoDB::MongoClient->new(
   host =>  $database_server,
   port =>  $database_port,
   db_name => $database_name,
   username=>  $username,
   password => $password,
   connectTimeoutMS => -1,
   socketTimeoutMS => -1,
);

my $out = $db->get_collection('<collection>')->find(...);
$out->immortal(1);
...