I write a lot of code that relies on precise periodic method calls. I've been using Python's futures
library to submit calls onto the runtime's thread pool and sleeping between calls in a loop:
executor = ThreadPoolExecutor(max_workers=cpu_count())
def remote_call():
# make a synchronous bunch of HTTP requests
def loop():
while True:
# do work here
executor.submit(remote_call)
time.sleep(60*5)
However, I've noticed that this implementation introduces some drift after a long duration of running (e.g. I've run this code for about 10 hours and noticed about 7 seconds of drift). For my work I need this to run on the exact second, and millisecond would be even better. Some folks have pointed me to asyncio
("Fire and forget" python async/await), but I have not been able to get this working in Python 2.7.
I'm not looking for a hack. What I really want is something akin to Go's time.Tick
or Netty's HashedWheelTimer
.