进程间通信Pipe详解 - Python双向管道send/recv

from multiprocessing import Process, Pipe

# 创建管道
parent_conn, child_conn = Pipe(duplex=True)

# 参数说明：
# duplex: True为双向管道（默认），False为单向管道
#   - duplex=True:  两个端点都可以send和recv
#   - duplex=False: 第一个端点只能recv，第二个端点只能send

# 连接端点的常用方法：
# conn.send(obj)       — 发送对象（自动pickle序列化）
# conn.recv()          — 接收对象（阻塞等待）
# conn.poll(timeout)   — 检查是否有数据可读
# conn.close()         — 关闭连接

from multiprocessing import Process, Pipe

def child_process(conn):
    """子进程：接收父进程消息并回复"""
    msg = conn.recv()
    print(f"子进程收到: {msg}")
    conn.send("你好，父进程！")
    conn.close()

if __name__ == '__main__':
    parent_conn, child_conn = Pipe()
    
    p = Process(target=child_process, args=(child_conn,))
    p.start()
    
    parent_conn.send("你好，子进程！")
    reply = parent_conn.recv()
    print(f"父进程收到: {reply}")
    
    p.join()

from multiprocessing import Process, Pipe

def sender(conn):
    """发送端"""
    for i in range(5):
        conn.send(f"消息{i}")
    conn.close()

def receiver(conn):
    """接收端"""
    while conn.poll():
        msg = conn.recv()
        print(f"收到: {msg}")
    conn.close()

if __name__ == '__main__':
    # duplex=False: recv_conn只能接收, send_conn只能发送
    recv_conn, send_conn = Pipe(duplex=False)
    
    p1 = Process(target=sender, args=(send_conn,))
    p2 = Process(target=receiver, args=(recv_conn,))
    
    p1.start()
    p2.start()
    
    p1.join()
    p2.join()

from multiprocessing import Process, Pipe
import time

def server(conn):
    """服务端：接收请求，返回响应"""
    while True:
        request = conn.recv()
        if request == "QUIT":
            break
        print(f"服务端收到请求: {request}")
        time.sleep(0.5)  # 模拟处理时间
        response = f"已处理: {request}"
        conn.send(response)
    conn.close()
    print("服务端关闭")

def client(conn):
    """客户端：发送请求，等待响应"""
    requests = ["查询用户", "更新数据", "删除记录"]
    for req in requests:
        conn.send(req)
        response = conn.recv()
        print(f"客户端收到响应: {response}")
    conn.send("QUIT")
    conn.close()
    print("客户端关闭")

if __name__ == '__main__':
    conn1, conn2 = Pipe()
    
    s = Process(target=server, args=(conn1,))
    c = Process(target=client, args=(conn2,))
    
    s.start()
    c.start()
    
    s.join()
    c.join()