Question

I have data coming in from an outside source (serial port in this case) roughly every 2.5 seconds.
I want to store ( in mysql) a sample of this data every 5 minutes, not every 2.5 seconds.
How would i implement this in python?
One can probably not use a sleep function since this will stop the rest of the script.

Answer 1

Check how much time has passed since the last save for each incoming event, and update the last-save timestamp after each save:

import time
lastsave = 0
def SaveEvent(data):
    # do what you need to save it
    ...


# I'm assuming there's some sort of event loop that 
# detects new events and directs them to some HandleEvent function

def HandleEvent(data):
    global lastsave
    if time.time() - lastsave > 300: 
    # this is in seconds, so 5 minutes = 300 seconds
        lastsave = time.time()
        SaveEvent(data)

If your application is multithreaded or multiprocessing you should also look into implementing a lock in the SaveEvent function to avoid concurrent saves.