在 python 中执行多个调度函数时如何处理线程中的错误？

Question

Hi I have multiple functions running with thread. I am wondering how do you handle error in running multiple threads where it does not affect the other threads that are running. When a function breaks, the other functions stops too. Do I use a try except for every schedule? Or is there a better way?

Current structure is like this.

#--------------------------------------------------------------------------run_threaded function

def run_threaded(job_func):
    job_thread = threading.Thread(target=job_func)
    job_thread.start()

#------------------------------------------------------------------------scheduler function

#scheduler
print('scheduler is starting')
schedule.every().day.at('06:30').do(run_threaded,lambda:functionA())
schedule.every().day.at('06:30').do(run_threaded,lambda:functionB())
schedule.every().day.at('06:30').do(run_threaded,lambda:functionC())
schedule.every().day.at('06:30').do(run_threaded,lambda:functionD())
schedule.every().day.at('06:30').do(run_threaded,lambda:fucntionE())
schedule.every().day.at('22:00').do(lambda:email())
schedule.every().day.at('22:15').do(lambda:writeFile())

while True:
    schedule.run_pending()
    sleep(1)

Answer 1

I want to start by stating that[Python.Docs]: threading - Thread-based parallelism does not actually do multithreading (on multiple CPU s), but it's more like a (lame) workaround ( gainarie ), because of GIL .
If you really want parallel execution, use [Python.Docs]: multiprocessing - Process-based parallelism .

But even if the above wasn't true, you actually do not have multithreading in your code. According to [ReadTheDocs.Schedule]: Schedule (if this is the module you are using), the methods (like do ) expect a function as a parameter (same as threading.Thread initializer), but you're passing a function call (the parentheses () at the end).
So, you have sequential runs of the functions you're passing, and when the 1 ^st one raises an exception, the whole program stops.

Taking the below line as an example:

schedule.every().day.at('06:30').do(run_threaded, lambda: functionA())

1. In [ReadTheDocs.Schedule]: Parallel execution (which was probably one of the sources of inspiration) the (target) function isn't called , so the above line should be:

    schedule.every().day.at('06:30').do(run_threaded, lambda: functionA) # functionA isn't called (no parentheses at the end) but it's rather passed as an argument

2. Not sure what's lambda purpose, things would look much simpler without it:

    schedule.every().day.at('06:30').do(run_threaded, functionA)

Apply the above steps to all the calls, and I think you'd be fine (functions runs that raise exceptions won't affect the ones that don't - at least that's the behavior in threading ), in spite of the following (in the Schedule documentation URL ):

When not to use Schedule

...

• Concurrent execution (multiple threads)