Python - Trap all signals

Question

In python 2.6 under Linux, I can use the following to handle a TERM signal:

import signal
def handleSigTERM():
    shutdown()
signal.signal(signal.SIGTERM, handleSigTERM)

Is there any way to setup a handler for all signals received by the process, other than just setting them up one-at-a-time?

user_229602 · Answer

You could just loop through the signals in the signal module and set them up.

for i in [x for x in dir(signal) if x.startswith("SIG")]:
  try:
    signum = getattr(signal,i)
    signal.signal(signum,sighandler)
  except (OSError, RuntimeError) as m: #OSError for Python3, RuntimeError for 2
    print ("Skipping {}".format(i))

user_10541608 · Answer

Works on Windows 10 and Python 3.7:

import signal
import time

def sighandler(signal,frame):
    print("signal",sig,frame)
    return

catchable_sigs = set(signal.Signals)
for sig in catchable_sigs:
    try:
        signal.signal(sig, sighandler)
        print("Setting ",sig)
        print ("value {}".format(sig))
    except (ValueError, OSError, RuntimeError) as m:
        print("Skipping ",sig)
        print ("Value {}".format(sig))


# press some keys or issue kill
x = 0
while x < 5:
    time.sleep(4)
    x += 1

Results:

Skipping  Signals.CTRL_C_EVENT
Value 0
Skipping  Signals.CTRL_BREAK_EVENT
Value 1
Setting  Signals.SIGINT
value 2
Setting  Signals.SIGILL
value 4
Setting  Signals.SIGFPE
value 8
Setting  Signals.SIGSEGV
value 11
Setting  Signals.SIGTERM
value 15
Setting  Signals.SIGBREAK
value 21
Setting  Signals.SIGABRT
value 22

user_622662 · Answer

For Python 3:

for sig in signal.Signals:
    try:
        signal.signal(sig, sighandler)
    except OSError:
        print('Skipping', sig)

user_9498974 · Answer

In Python3.8 we've got a new function signal.valid_signals() https://docs.python.org/3/library/signal.html#signal.valid_signals

import signal
for sig in signal.valid_signals():
    print(f"{sig:2d}",sig)

Python - Trap all signals

8 Answers