py_ad_1_7.py

"""
Section 1
Multithreading - Thread(5) - Prod and Cons Using Queue
Keyword - 생산자 소비자 패턴(Producer/Consumer Pattern)

"""
"""

Producer-Consumer Pattern
(1).멀티스레드 디자인 패턴의 정석
(2).서버측 프로그래밍의 핵심
(3).주로 허리역할 중요

Python Event 객체
(1). Flag 초기값(0)
(2). Set() -> 1, Clear() -> 0, Wait(1 -> 리턴, 0 -> 대기), isSet() -> 현 플래그 상태

"""

import concurrent.futures
import logging
import queue
import random
import threading
import time

# 생산자
def producer(queue, event):
    """네트워크 대기 상태라 가정(서버)"""
    while not event.is_set():
        message = random.randint(1, 11)
        logging.info("Producer got message: %s", message)
        queue.put(message)

    logging.info("Producer received event. Exiting")

# 소비자
def consumer(queue, event):
    """응답 받고 소비하는 것으로 가정 or DB 저장"""
    while not event.is_set() or not queue.empty():
        message = queue.get()
        logging.info(
            "Consumer storing message: %s (size=%d)", message, queue.qsize()
        )

    logging.info("Consumer received event. Exiting")

if __name__ == "__main__":
    # Logging format 설정
    format = "%(asctime)s: %(message)s"
    logging.basicConfig(format=format, level=logging.INFO,
                        datefmt="%H:%M:%S")

    # 사이즈 중요
    pipeline = queue.Queue(maxsize=10)

    # 이벤트 플래그 초기 값 0
    event = threading.Event()

    # With Context 시작
    with concurrent.futures.ThreadPoolExecutor(max_workers=2) as executor:
        executor.submit(producer, pipeline, event)
        executor.submit(consumer, pipeline, event)

        # 실행 시간 조정
        time.sleep(0.1)

        logging.info("Main: about to set event")
        
        # 프로그램 종료
        event.set()