There is function which need to sleep 10 second. But in the meantime, I don't want it to block my main function. How to deal with that? I try to do like that. However, it still block my main function.
def tester():
pool.size=2;
pool=multiprocessing.Pool(pool_size);
pool.apply_async(send_mail, args=("test",));
pool.close();
pool.join();
print "email is done";
the main function will call this function.
pool.join();
is your blocker. remove it to not block.
https://docs.python.org/2/library/multiprocessing.html#multiprocessing.Process.join
EDIT:
import threading
print "start"
th = threading.Thread(target=tester)
th.daemon = False
print "thread start"
th.start()
print "executing other code"
Not sure why you are using Pool. You are spawning 2 subprocesses to send a single email? What about just spawning a single process. The following should get you started. (I put a "sleep(30)" where you would actually call send_mail)
from multiprocessing import Process, Queue
from time import sleep
def wrap_send_email(q, msg):
try:
sleep(30)
q.put( [ msg, 'mail sent sucessfully'] )
except:
q.put( [ msg, 'mail not sent successfully'] )
def test():
q = Queue()
p = Process(target=wrap_send_email, args=(q, 'test message'))
p.start()
while p.is_alive():
print("Doing stuff while the other process is working.")
sleep(5)
print(q.get())
p.join()
print "email is done" after the join. If you remove the join, that statement will execute immediately and not necessarily after the email is done. I also am not sure why you need a pool of 2 for this application. A pool of 1 seems sufficient, in which case, why use a Pool at all, just use a Process.