[Python] Wake up a blocking redis call inside a signal handler in python

I need to wake up a blocked pop (redis client) on a list thru a signal handling (in this case SIGUSR1)

This is the sample code:

import redis
import signal

r = redis.Redis()

def handler(signal, frame):
q = redis.Redis()
q.rpush('test', 1)
print 'sign arrived'

signal.signal(signal.SIGUSR1, handler)

print 'start'
print r.blpop('asd')
print 'end'


the output of this code is

start
// here I send the signal with "$ kill -10 <pid>"
sign arrived


and stop

other informations:

• the result of the push inside the handler is 1 (it should mean that an element have actually been inserted in the list)
• if I open a parallel redis-cli shell, no element is shown with "LRANGE" even after the signal handling
• redis-cli command "CLIENT LIST" shows the blpop client

What is wrong? thanks in advance

update


if I duplicate the push, works:

def handler(signal, frame):
q = redis.Redis()
q.rpush('test', 1)
q.rpush('test', 1)
print 'sign arrived'


And no other message seems last in the redis queue. It looks like the first push disappears...

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