real world side effect

crap_again.py

def check_job_status(job):
    if job.status=='error':
        raise Exception

def task(...):
    """
    It is a task of thread. When it detects job (parent) failed,
    it should stop and raise exception so that the thread stop, too.
    """
    try:
        p = subprocess.Popen(cmd, ...)
        while 1:
            line = p.stdout.readline()
            if (line=='' and p.poll() is not None) or check_job_status(job):
                break
        # ...
        # about 100 lines...
        # ...
    except:
        if 'p' in locals() and p.poll() is not None:
            p.terminate()
            stdoutdata, stderrdata = p.communicate()
        raise Exception