a simple loop

[cuihairu]

1. The kill method is provided to facilitate its own internal calls. Some programs need to support internal shutdown (not the way to accept signals).

# import module
from GracefulKiller import GracefulKiller
    
# create killer
killer = GracefulKiller()

# An rpc program can call the interface to shut down the program
killer.kill()

2. A default thread loop is provided.

Threaded Loop may not be the best option, but a simple implementation.

# import module
from GracefulKiller import GracefulKiller

# create killer
killer = GracefulKiller()

# create loop object and start loop, wait one second after each loop. 
Loop(killer, 1).start()

3. singleton

man  signal

# return :

signal() returns the previous value of the signal handler, or SIG_ERR on error.

GracefulKiller objects create multiple, and only one of them takes effect.

4. shutdown handler

# import module
from GracefulKiller import GracefulKiller, Loop

# Called when graceful shutdown 
def shutdown_handler():
    print("shutdown")
    
# create killer
killer = GracefulKiller(shutdown_handler)

# loop
Loop(killer, 1).start()

# shutdown
killer.kill()

# print
"shutdown"

[MaxMaxoff]

@cuihairu, could you please provide some description and use cases for your changes.

[cuihairu]

@MaxMaxoff my English is not too good, I wish I could express it clearly.

[MaxMaxoff]

could you please update killer and delay with default values, like killer=None, delay=1 or etc.

[MaxMaxoff]

why it can't be just like this:
assert killer and isinstance(killer, GracefulKiller)?

[MaxMaxoff]

Looks more simple, what do you think?
while not self.killer.kill_now: time.sleep(self.delay)

[MaxMaxoff]

@cuihairu, now I understand what you're offer in this PR.
Could you please update your code according to my comemnts.

[MaxMaxoff]

you can pass it if you will define default values for delay