====== multiprocessing ======

  * 자식프로세스 출력 redirection

<code python>

import app
import io
import sys
from multiprocessing import Process

def run_app(some_param):
    sys.stdout = io.TextIOWrapper(open(sys.stdout.fileno(), 'wb', 0), write_through=True)
    app.run()

app_process = Process(target=run_app, args=('some_param',))
app_process.start()
# Use app_process.termninate() for python <= 3.7.
app_process.kill() 

# https://stackoverflow.com/questions/7714868/python-multiprocessing-how-can-i-reliably-redirect-stdout-from-a-child-process
</code>

<code python>
original_stdout = sys.stdout
buffer = deque(maxlen=128)

class IOLoggerWrapper(io.StringIO):
    def write(self, string):
        buffer.append(string)
        return len(string)
        
root = logging.getLogger()
handler = logging.StreamHandler(IOLoggerWrapper())
formatter = logging.Formatter("[%(asctime)s][%(name)s][%(levelname)s][%(message)s]")
handler.setFormatter(formatter)
root.addHander(handler)

class IOWrapper(io.StringIO):
    def write(self, string):
        original_stdout.write(string)
        buffer.append(string)
        return len(string)
        
io_wrapper = IOWrapper()
sys.stdout = io_wrapper
sys.stderr = io_wrapper
</code>


===== multiprocessing 대체 모듈 =====

  * Uber Fiber
    * https://uber.github.io/fiber/
    * multiprocessing과 사용법이 동일한 분산 컴퓨팅

  * loky: resuable pool executer
    * https://pypi.org/project/loky/

  * Array 공유
    * https://pypi.org/project/SharedArray/