最近在服务器上部署了一个镜像，发现停止的时候很慢，需要 10 多妙。偶然看到一篇文章
docker stop 先会用信号 15(SIGTERM)去 kill，如果在指定超时时间内无法 kill，就会用信号 9(SIGKILL)去 kill。
SIGTERM 和 SIGKILL 区别： SIGKILL 和 SIGTERM 都会终止进程，SIGTERM 会先清除临时文件、释放其它资源，然后再关闭进程，俗称优雅的退出进程。SIGKILL 是直接终止进程。
摘自man signal
| No | Name | Default Action | Description |
|---|---|---|---|
| 1 | SIGHUP | terminate process | terminal line hangup |
| 2 | SIGINT | terminate process | interrupt program |
| 3 | SIGQUIT | create core image | quit program |
| 4 | SIGILL | create core image | illegal instruction |
| 5 | SIGTRAP | create core image | trace trap |
| 6 | SIGABRT | create core image | abort program (formerly SIGIOT) |
| 7 | SIGEMT | create core image | emulate instruction executed |
| 8 | SIGFPE | create core image | floating-point exception |
| 9 | SIGKILL | terminate process | kill program |
| 10 | SIGBUS | create core image | bus error |
| 11 | SIGSEGV | create core image | segmentation violation |
| 12 | SIGSYS | create core image | non-existent system call invoked |
| 13 | SIGPIPE | terminate process | write on a pipe with no reader |
| 14 | SIGALRM | terminate process | real-time timer expired |
| 15 | SIGTERM | terminate process | software termination signal |
| 16 | SIGURG | discard signal | urgent condition present on socket |
| 17 | SIGSTOP | stop process | stop (cannot be caught or ignored) |
| 18 | SIGTSTP | stop process | stop signal generated from keyboard |
| 19 | SIGCONT | discard signal | continue after stop |
| 20 | SIGCHLD | discard signal | child status has changed |
| 21 | SIGTTIN | stop process | background read attempted from control terminal |
| 22 | SIGTTOU | stop process | background write attempted to control terminal |
| 23 | SIGIO | discard signal | I/O is possible on a descriptor (see fcntl(2)) |
| 24 | SIGXCPU | terminate process | cpu time limit exceeded (see setrlimit(2)) |
| 25 | SIGXFSZ | terminate process | file size limit exceeded (see setrlimit(2)) |
| 26 | SIGVTALRM | terminate process | virtual time alarm (see setitimer(2)) |
| 27 | SIGPROF | terminate process | profiling timer alarm (see setitimer(2)) |
| 28 | SIGWINCH | discard signal | Window size change |
| 29 | SIGINFO | discard signal | status request from keyboard |
| 30 | SIGUSR1 | terminate process | User defined signal 1 |
| 31 | SIGUSR2 | terminate process | User defined signal 2 |
为程序添加 SIGTERM 信号处理。
只要使用 signal 模块注册一个信号处理事件就行。
signal.signal 要传入两个参数。
第一个参数是信号值，第二个是回调方法。
import signal
import os
import time
exit = 0
def receive_signal(signum, stack):
global exit
print('Received:', signum)
exit = 1
signal.signal(signal.SIGTERM, receive_signal)
signal.signal(signal.SIGINT, receive_signal)
print('My PID is:', os.getpid())
if __name__ == '__main__':
while True:
if exit:
break
print('Waiting...')
time.sleep(3)
asyncio 的 eventloop 提供 add_signal_handler 方法，用法和 signal.signal 一样。
这里展示了两种用法，第一种是通过偏函数传入参数，第二种是通过 ensure_future 将 handler_signal 放入 eventloop 里
import asyncio
import functools
import os
import signal
async def main():
while True:
print('Wait...')
await asyncio.sleep(3)
def handle_signal(loop):
print('loop close....')
loop.stop()
if __name__ == '__main__':
print('My PID:', os.getpid())
loop = asyncio.get_event_loop()
loop.add_signal_handler(signal.SIGTERM, functools.partial(handle_signal, loop=loop))
loop.add_signal_handler(
signal.SIGINT, lambda: asyncio.ensure_future(handle_signal(loop=loop))
)
asyncio.ensure_future(main())
loop.run_forever()