[英]Python Pool - How do I keep Python Process running when I get a timeout exception?
我正在使用 Python 多處理庫。 每當其中一個進程拋出超時錯誤時,我的應用程序就會自行結束。 我想保持流程正常進行。
我有一個訂閱隊列並監聽傳入消息的 function:
def process_msg(i):
#get new message from the queue
#process it
import time
time.sleep(10)
return True
我創建了一個創建 6 個進程並執行上面的 process_msg() function 的池。 當 function 超時時,我希望池再次調用 function 並等待新消息而不是退出:
if __name__ == "main":
import multiprocessing
from multiprocessing import Pool
pool = Pool(processes=6)
collection = range(6)
try:
val = pool.map_async(process_msg, collection)
try:
res = val.get(5)
except TimeoutError:
print('timeout here')
pool.close()
pool.terminate()
pool.join()
代碼運行,當我超時時,應用程序自行終止。
我想要它做的是打印發生的超時並再次調用相同的 function 。
什么是正確的方法?
這是一個有效程序的框架。 您遇到的主要問題是使用pool.terminate
,它“立即停止工作進程而不完成未完成的工作”(請參閱文檔)。
from multiprocessing import Pool, TimeoutError
def process_msg(i):
#get new message from the queue
#process it
import time
print(f"Starting to sleep, proxess # {i}")
time.sleep(10)
return True
def main():
print("in main")
pool = Pool(processes=6)
collection = range(6)
print("About to spawn sub processes")
val = pool.map_async(process_msg, collection)
while True:
try:
print("Waiting for results")
res = val.get(3)
print(f"Res is {res}")
break
except TimeoutError:
print("Timeout here")
print("Closing pool")
pool.close()
# pool.terminate() # do not terminate - it kill the child processes
print ("Joining pool")
pool.join()
print("exiting main")
if __name__ == "__main__":
main()
該代碼的output為:
in main
About to spawn sub processes
Waiting for results
Starting to sleep, proxess # 0
Starting to sleep, proxess # 1
Starting to sleep, proxess # 2
Starting to sleep, proxess # 3
Starting to sleep, proxess # 4
Starting to sleep, proxess # 5
Timeout here
Waiting for results
Timeout here
Waiting for results
Timeout here
Waiting for results
Res is [True, True, True, True, True, True]
Closing pool
Joining pool
exiting main
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