Your process has not left the terminal. After the terminal is closed, all child processes associated with the terminal will be terminated without any output.
It is recommended to make spaider.py into a daemon process, out of the control of the terminal.

logging

Thank you for your answers. The real reason has been found. It is because too much print output during the debugging process exceeds the cache and causes the process to end.

Although you execute the process in the background, it is not detached from the terminal that started the process. Therefore, the parent process shell terminal is closed and the child process will also be closed.

Solution 1, you can refer to How to make a Python script run like a service or daemon in Linux, which teaches you how to program a process into a daemon process under Linux. The sample program is quite long, so I’ll explain it at the end.

Solution 2, there are python libraries that can daemonize their own processes, and there are quite a few. For example, python-daemon. Usage examples are as follows:

import daemon

def do_main_program():
    pass  # 你的程序

with daemon.DaemonContext():
    do_main_program()
    

Additional solution 1 processing:

# -*- coding: utf-8 -*-
import os
import sys
import datetime

def daemonize(stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
    try:
        pid = os.fork()
        if pid > 0:
            sys.exit(0)  # Exit first parent.
    except OSError, e:
        sys.stderr.write("fork #1 failed: (%d) %s\n" % (e.errno, e.strerror))
        sys.exit(1)
    # Decouple from parent environment.
    os.chdir("/")
    os.umask(0)
    os.setsid()
    # Do second fork.
    try:
        pid = os.fork()
        if pid > 0:
            sys.exit(0)  # Exit second parent.
    except OSError, e:
        sys.stderr.write("fork #2 failed: (%d) %s\n" % (e.errno, e.strerror))
        sys.exit(1)
    # Redirect standard file descriptors.
    si = file(stdin, 'r')
    so = file(stdout, 'a+')
    se = file(stderr, 'a+', 0)
    os.dup2(si.fileno(), sys.stdin.fileno())
    os.dup2(so.fileno(), sys.stdout.fileno())
    os.dup2(se.fileno(), sys.stderr.fileno())
    
if __name__ == "__main__":
    daemonize()
    # 然后开始执行你的其他程序。