如何從python程序發送信號？

Question

我有這樣的代碼，它會監聽USR1信號

import signal 
import os 
import time 

def receive_signal(signum, stack): 
    print 'Received:', signum 

signal.signal(signal.SIGUSR1, receive_signal) 
signal.signal(signal.SIGUSR2, receive_signal) 

print 'My PID is:', os.getpid() 

while True: 
    print 'Waiting...' 
    time.sleep(3) 

這工作時，我發出信號，kill -USR1 pid

但我怎麼可以從發送上面的Python腳本中相同的信號，使10秒後它自動發送USR1也收到它，我不必打開兩個終端來檢查它？

Answer 1

如果你願意搭上SIGALRM，而不是SIGUSR1，請嘗試：

signal.alarm(10) 

否則，你需要啓動另一個線程：

import time, os, signal, threading 
pid = os.getpid() 
thread = threading.Thread(
    target=lambda: (
    time.sleep(10), 
    os.kill(pid, signal.SIGUSR1))) 
thread.start() 

因此，該程序：

import signal 
import os 
import time 

def receive_signal(signum, stack): 
    print 'Received:', signum 

signal.signal(signal.SIGUSR1, receive_signal) 
signal.signal(signal.SIGUSR2, receive_signal) 
signal.signal(signal.SIGALRM, receive_signal) # <-- THIS LINE ADDED 

print 'My PID is:', os.getpid() 

signal.alarm(10)        # <-- THIS LINE ADDED 

while True: 
    print 'Waiting...' 
    time.sleep(3) 

產生此輸出：

$ python /tmp/x.py 
My PID is: 3029 
Waiting... 
Waiting... 
Waiting... 
Waiting... 
Received: 14 
Waiting... 
Waiting... 

Answer 2

您可以使用os.kill()：

os.kill(os.getpid(), signal.SIGUSR1) 

把你的代碼，這在任何地方，你想從發送信號。