Timeout in mutli-threaded script

Question

I'm trying to timeout a line of code within a thread (not the main thread).

Signal only works in main thread, so I can't use that.

The line I want to limit is a web request with the requests library:

s.get("https://www.google.com/")

I can't use requests built-in timeout, because it doesn't always time out under certain conditions.

do you have access to the thread where you do s.get("https://www.google.com/") ? — ranjith, Mar 14 '19 at 03:09
@ranjith not sure what you mean, but yeah it's all in 1 script that i wrote myself — User, Mar 14 '19 at 03:10
i meant are you using say pythons threading library or something similar ? As in th = threading.Thread(target = your_function, name="thread_name"); th.start() ? — ranjith, Mar 14 '19 at 03:12
@ranjith and within that thread, there is like 50 lines of code and a few nested loops. i just need to wrap the web requests somehow. — User, Mar 14 '19 at 03:20
@User can you specify why you can't use requests built-in timeout? — alberand, Mar 14 '19 at 10:55

score 0 · Answer 1 · answered Mar 14 '19 at 03:33

If you are using python's standard threading library, I don't think there is an easy way to terminate the thread once it has started. There are some options mentioned in this thread (:D), you could perhaps try. If you don't care when the thread completes and just want control back, you can provide timeout in join method. It would look like below,

th = threading.Thread(target=f)
th.start()    #starts thread
th.join(timeout=10) # you get control back in 10 seconds, but thread could still be running
if th.is_alive():
    print("still alive")

Other option (which I like) would be to use concurrent library,

from concurrent.futures import ThreadPoolExecutor
with ThreadPoolExecutor(max_workers=1) as executor:
    future = executor.submit(pow, 323, 1235)
    print(future.result(timeout=10))    #within 10 seconds if result isn't returned you will get TimeoutError

Quoting from docs on result(timeout=None),

If the call hasn’t completed in timeout seconds, then a concurrent.futures.TimeoutError will be raised. timeout can be an int or float. If timeout is not specified or None, there is no limit to the wait time

So you suggest putting the request into another thread? So a thread created within a thread? — User, Mar 14 '19 at 03:34
if you have code that aren't blocked on the results, why not — ranjith, Mar 14 '19 at 03:35
well the code after of course relies on the response of the request — User, Mar 14 '19 at 03:38
ok, you could still create new thread for http call and if you don't get results in time, proceed with your other part of the code — ranjith, Mar 14 '19 at 03:58

Timeout in mutli-threaded script

1 Answers1