# assigns a job to a worker process.
# :param 0:     job.
# :return:
sub assign_job {
    my ($job) = @_;
    my $pid = open my $pipe => "-|";                    # create worker process and connect it using a pipe.
    Debug::dlog("spawned process : $pid");
    die "Failed to fork: $!" unless defined $pid;       # check that creation was successfull.
    my $routine = $job->get_routine();                  # get routine to execute.
    my $params = $job->get_params();                    # get parameters to pass.
    unless ($pid) {                                     # the following code is only executed in the worker process:
        $ENV{"PATH"} = "/usr/bin";                      # delete context.
        my $return = $routine->(@$params);              # execute routine.
        my $dump = Dumper($return);                     # serialize the returned object.
        print($dump);                                   # print data string to pipe.
        Debug::dlog("process ".$$." dumped ".length($dump)." chars");
        exit;                                           # terminate process.
    } else {                                            # only in parent process:
        my $worker = new Worker($pipe, $pid);           # construct new worker object.
        push(@Dispatcher::workers, $worker);            # save worker object.
    }
}