【Python多进程】报错EOFError: Ran out of input

Python多进程multiprocessing报错EOFError: Ran out of input

在使用python多进程multiprocessing过程中，报错

该错误表明是文件读写发生错误。这是由于PyCharm等编辑器开启进程时是需要读取代码源文件的缘故。

错误复现

# main.py
import os
import time

import multiprocessing


def worker(process_num):
    """进程的工作函数"""
    print(f"Worker {process_num} is running with PID: {os.getpid()}")
    time.sleep(0.2)
    return os.getpid()


if __name__ == "__main__":
    # 创建多个进程
    num_processes = 4
    processes = []
    for i in range(num_processes):
        process = multiprocessing.Process(target=worker, args=(i,))
        processes.append(process)

    # 启动所有进程
    for process in processes:
        process.start()

    # 等待所有进程结束
    for process in processes:
        process.join()

    print("All processes have finished.")

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

此时需要开启子进程的函数文件和主进程在同一个文件中

解决

# worker_module.py
import os
import time


def worker(process_num):
    """进程的工作函数"""
    print(f"Worker {process_num} is running with PID: {os.getpid()}")
    time.sleep(0.2)
    return os.getpid()


# main.py
import multiprocessing
import worker_module

if __name__ == "__main__":
    # 创建多个进程
    num_processes = 4
    processes = []
    for i in range(num_processes):
        process = multiprocessing.Process(target=worker_module.worker, args=(i,))
        processes.append(process)

    # 启动所有进程
    for process in processes:
        process.start()

    # 等待所有进程结束
    for process in processes:
        process.join()

    print("All processes have finished.")

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34

将需要开启子进程的代码单独放入文件worker_module.py，再在主进程代码main.py中导入。