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Python: 使用 faulthandler 模块获取运行中进程的 traceback 信息

Python 3.3 新增了一个 faulthandler 模块，可以输出运行中进程的 traceback 信息，可以用来作为调试运行中的 Python 进程的一种手段。

特点及限制

模块本身是使用 C 实现的，所以有如下特点和限制：

特点

• 在 Segmentation fault 或者 Python 死锁时仍然可以输出 traceback 信息

限制

• 只能用于信号安全的函数
• 只支持 ASCII 字符。程序使用 backslashreplace 作为编码时的 error handler
• 每个字符串最长只能包含 500 个字符
• 只显示文件名，函数名和行号（不显示源码）
• 最大支持 100 个 frame 和 100 个线程
• 显示顺序是翻转的：最近的调用显示在前面

安装

Python 3.3 自带了这个模块，Python 2.x 可以通过一下方式安装:

pip install faulthandler

使用示例

手动输出 traceback 信息

测试函数:

import time

def do(x):
    x = x * 3
    time.sleep(x * 60)

def main():
    threads = []
    for x in range(1, 3):
        t = Thread(target=do, args=(x,))
        t.start()
    for x in threads:
        x.join()

使用 faulthandler 输出所有线程的 traceback 信息:

In [1]: import test

In [2]: test.main()

In [3]: import faulthandler

In [4]: faulthandler.dump_traceback()
Thread 0x0000700009d66000 (most recent call first):
  File "/Users/xxx/tmp/test_faulthandler/test.py", line 7 in do
  File "/xxx/lib/python3.6/threading.py", line 864 in run
  File "/xxx/lib/python3.6/threading.py", line 916 in _bootstrap_inner
  File "/xxx/lib/python3.6/threading.py", line 884 in _bootstrap

Thread 0x0000700009863000 (most recent call first):
  File "/Users/xxx/tmp/test_faulthandler/test.py", line 7 in do
  File "/xxx/lib/python3.6/threading.py", line 864 in run
  File "/xxx/lib/python3.6/threading.py", line 916 in _bootstrap_inner
  File "/xxx/lib/python3.6/threading.py", line 884 in _bootstrap

Thread 0x0000700009360000 (most recent call first):
  File "/xxx/lib/python3.6/threading.py", line 295 in wait
  File "/xxx/lib/python3.6/threading.py", line 551 in wait
  File "/xxx/lib/python3.6/site-packages/IPython/core/history.py", line 834 in run
  File "/xxx/lib/python3.6/site-packages/IPython/core/history.py", line 60 in needs_sqlite
  File "<decorator-gen-23>", line 2 in run
  File "/xxx/lib/python3.6/threading.py", line 916 in _bootstrap_inner
  File "/xxx/lib/python3.6/threading.py", line 884 in _bootstrap

Current thread 0x00007fffe03873c0 (most recent call first):
  File "<ipython-input-4-6b8299023d33>", line 1 in <module>
  File "/xxx/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2881 in run_code
  File "/xxx/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2827 in run_ast_nodes
  File "/xxx/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2717 in run_cell
  File "/xxx/lib/python3.6/site-packages/IPython/terminal/interactiveshell.py", line 446 in interact
  File "/xxx/lib/python3.6/site-packages/IPython/terminal/interactiveshell.py", line 455 in mainloop
  File "/xxx/lib/python3.6/site-packages/IPython/terminal/ipapp.py", line 348 in start
  File "/xxx/lib/python3.6/site-packages/traitlets/config/application.py", line 658 in launch_instance
  File "/xxx/lib/python3.6/site-packages/IPython/__init__.py", line 119 in start_ipython
  File "/xxx/bin/ipython", line 11 in <module>

In [5]: