A currency exchange thread updates exchange rate once a minute. If the
thread faield to update currency rate for 5 hours, it should inform
main() for a clean exit. This has to be done gracefully, because main()
could be doing something delicate.
I, a newbie, read all the thread sync tool, and wasn't sure which one to
use. In fact I am not sure if there is a need of thread sync, because
there is no racing cond. I thought of this naive way:
class CurrencyExchange():
def __init__(in_case_callback):
this.callback = in_case_callback
def __run__():
while time.time() - self.rate_timestamp < 5*3600:
... # update exchange rate
if success:
self.rate_timestamp == time.time()
time.sleep(60)
this.callback() # rate not updated 5 hours, a crisis
def main():
def callback()
Go_On = False
agio = CurrencyExchange(in_case = callback)
agio.start()
Go_On = True
while Go_On:
do_something_delicate(rate_supplied_by=agio)
As you can see, if there is no update of currency rate for 5 hours, the
CurrencyExchange object calls the callback, which prevents main() from
doing the next delicate_thing, but do not interrupt the current
delicate_thing.
This seems OK, but doesn't look pythonic -- replacing callback() with a
lambda doesn't help much, it still look naive. What is the professional
way in this case?
Thanks in advance!
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