Writing to stdout (host command line) from another thread

[gswifort]

I wonder if we can somehow protect stdout from being written to from other threads.

For example, I run an http server that MUST run in a separate thread, I have no influence on whether the http library will use logger.warning(...), which by default writes to stdout.

[rdesparbes]

It does not directly answer your question, but can't you do something like:

logger = logging.getLogger("flask")  # Or whatever web app framework you're using
logger.setLevel(logging.CRITICAL)  # Basically mutes the logger of the 'flask' module

[gswifort]

in my individual case I can, but I'm looking for something universal, especially since I don't want to mute it, I just want to display messages safely (writing to the host command line from another thread is not safe).

[CEXT-Dan]

I can add a mutex in stdout_redirector, would that help?

[gswifort]

Can you use my logic in write function? registerOnIdleWinMsg

[CEXT-Dan]

try Commit 2ca12c0
not sure it will stick, we'll have to test for side effects

[CEXT-Dan]

my test

import concurrent.futures
from threading import current_thread

def threadID(n):
    print(current_thread().name, n)
    return current_thread().name

@Ap.Command()
def doitfast():
    try:
        res = None
        with concurrent.futures.ThreadPoolExecutor(max_workers=8) as executor:
            results = executor.map(threadID, range(16))
            res = set(results)

        # print(res)

    except Exception as err:
        traceback.print_exception(err)

output:

Command: ThreadPoolExecutor-4_0 0
ThreadPoolExecutor-4_0 1
ThreadPoolExecutor-4_0 2
ThreadPoolExecutor-4_0 3
ThreadPoolExecutor-4_0 4
ThreadPoolExecutor-4_0 5
ThreadPoolExecutor-4_0 6
ThreadPoolExecutor-4_0 7
ThreadPoolExecutor-4_0 8
ThreadPoolExecutor-4_2 9
ThreadPoolExecutor-4_2 10
ThreadPoolExecutor-4_2 11
ThreadPoolExecutor-4_1 12
ThreadPoolExecutor-4_1 13
ThreadPoolExecutor-4_1 14
ThreadPoolExecutor-4_2 15

[gswifort]

It seems to work very well 🚀

[CEXT-Dan]

Cool, we’ll need to keep an eye on it.