用kill信号输入pdb [英] enter pdb with kill signal

问题描述

在最近的项目中，我想在生产使用状态下调试程序.生产环境非常复杂，因此我一发现问题就想调试程序.

In a recent project, I want to debug my program in production use state. The production environment is very complicated so I want to debug the program whenever I find a problem.

这是我要实现的目标:每当我要调试时，我都会向程序发送终止信号，并希望出现pdb调试器.是这样的:

This is what I want to achieve: whenever I want to debug, I will send a kill signal to the program and hopefully pdb debugger will appear. It is something like this:

import pdb
import signal
import time

def handler(signal, frame):
  pdb.set_trace()

signal.signal(signal.SIGTERM, handler)
a=1
while True:
  a+=1
  time.sleep(1)

但是，由于我必须使用nohup运行程序，所以所有输出都将重定向到nohup.out，因此我无法与pdb进行交互.

However, since I have to run the program with nohup, all output will be redirected to nohup.out, so there's no way I can interact with pdb.

有什么类似的方法吗?

推荐答案

如果从终端运行程序，则可以使用tty命令来记录 您所在的tty设备，并将其传递到环境中的程序中:

If you run the program from a terminal you can use the tty command to note the tty device you are on, and pass it to the program in the environment:

TTY=`tty` nohup ./myprog.py

，然后在处理程序中再次打开tty并将stdin和stdout设置为文件:

and then in the handler open the tty again and set stdin and stdout to the file:

import sys,os

def handler(signal, frame):
  tty = os.getenv('TTY')
  sys.stdin = sys.stdout = open(tty,"r+")
  pdb.set_trace()

---

如果按照注释中的说明从当前tty分离程序，则您 可以尝试使用相同的python代码进行类似的操作.这次使用以下程序运行程序:

---

If you are detaching the program from the current tty as in your comment, then you can try something similar, with the same python code. This time run your program with:

TTY=/tmp/link  nohup ./myprog.py &

并关闭终端.打开一个新终端，并创建指向该新tty的缺少链接:

and close the terminal. Open a new terminal and create the missing link to this new tty:

ln -s `tty` /tmp/link

然后在一行中给出kill命令，以信号通知python进程，并且 然后立即执行sleep.这样一来，壳就不再与之竞争 从tty输入的pdb.例如，一行:

Then give, in one single line, the kill command to signal the python process, and then immediately do a sleep. This is so that the shell is no longer competing with pdb for input from the tty. Eg, on one line:

kill -term $pid; sleep 99999

然后，您将让pdb连接到/tmp/link，这是您的tty.退出pdb时，键入 ctrl-c 将停止睡眠.

You will then have pdb connect to /tmp/link, which is your tty. When you quit pdb, typing ctrl-c will stop the sleep.

如果您需要在pdb中使用 ctrl-c ，并且您正在使用bash， 将sleep 99999替换为suspend.退出pdb时，使用终端的菜单发送信号sigcont 取回暂停的bash的过程.

If you need to use ctrl-c in pdb, and you are using bash, replace the sleep 99999 by suspend. When you quit pdb, use your terminal's menus to send signal sigcont to the process to get back the suspended bash.

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