python traceback 异常的获取与处理

traceback.print_exc()
traceback.format_exc()
traceback.print_exception()

简单说下这三个方法是做什么用的：

1、print_exc()：
    是对异常栈输出
2、format_exc()：
    是把异常栈以字符串的形式返回，print(traceback.format_exc()) 就相当于traceback.print_exc()
3、print_exception()：
    traceback.print_exc()实现方式就是traceback.print_exception(sys.exc_info())，可以点        sys.exc_info()进去看看实现

测试代码如下：

def func(a, b):
    return a / b


if __name__ == '__main__':
    import sys
    import time
    import traceback

    try:
        func(1, 0)
    except Exception as e:
        print('***', type(e), e, '***')
        time.sleep(2)

        print("***traceback.print_exc():*** ")
        time.sleep(1)
        traceback.print_exc()
        time.sleep(2)

        print("***traceback.format_exc():*** ")
        time.sleep(1)
        print(traceback.format_exc())
        time.sleep(2)

        print("***traceback.print_exception():*** ")
        time.sleep(1)
        traceback.print_exception(*sys.exc_info())

运行结果：

*** <class 'ZeroDivisionError'> division by zero ***
***traceback.print_exc():*** 
Traceback (most recent call last):
  File "/home/l/PycharmProjects/test_modules/tasks.py", line 26, in <module>
    func(1, 0)
  File "/home/l/PycharmProjects/test_modules/tasks.py", line 17, in func
    return a / b
ZeroDivisionError: division by zero
***traceback.format_exc():*** 
Traceback (most recent call last):
  File "/home/l/PycharmProjects/test_modules/tasks.py", line 26, in <module>
    func(1, 0)
  File "/home/l/PycharmProjects/test_modules/tasks.py", line 17, in func
    return a / b
ZeroDivisionError: division by zero

***traceback.print_exception():*** 
Traceback (most recent call last):
  File "/home/l/PycharmProjects/test_modules/tasks.py", line 26, in <module>
    func(1, 0)
  File "/home/l/PycharmProjects/test_modules/tasks.py", line 17, in func
    return a / b
ZeroDivisionError: division by zero

可以看出，三种方式打印结果是一样的。在开发时，做调试是很方便的。也可以把这种异常栈写入日志。

logging.exception(ex)

# 指名输出栈踪迹, logging.exception的内部也是包了一层此做法
logging.error(ex, exc_info=1) 

# 更加严重的错误级别 
logging.critical(ex, exc_info=1) 

# 我直接copy的，未尝试。有时间会试下的

python 还有一个模块叫cgitb，输出的error非常详情。

# -*- coding: utf-8 -*-
def func(a, b):
    return a / b

try:
    func(1, 0)
except Exception as e:
    import cgitb
    cgitb.enable(format='text')
    func(1, 0)

控制台打印结果