The traceback module using Python exception record displaying

And abnormal fight is already a programmer commonplace. Many times we need to print out all exception information. The more common method is the direct use of an exception to capture:

import time

def error_func():
    raise ValueError("错误出现")

if __name__ == '__main__':
    try:
        error_func()
    except ValueError as e:
        print(e)

    time.sleep(1)
    print('继续执行')

Print results are as follows:

错误出现
继续执行

However, the above code just print the abnormality information, and no abnormal type of printing. If we project in exception handling many things you need along with 异常出现的位置, 异常信息, 异常的类型they are printed out and help us troubleshoot the error.

Use traceback module format_exc way to print a complete anomaly

Sample code is as follows:

import time
def error_func():
    raise ValueError("错误出现")

if __name__ == '__main__':
    try:
        error_func()
    except ValueError:
        import traceback
        print(traceback.format_exc())

    time.sleep(1)
    print('继续执行')

The results are as follows:

Traceback (most recent call last):
  File "D:/auto/pro/error_test.py", line 9, in <module>
    error_func()
  File "D:/auto/pro/error_test.py", line 4, in error_func
    raise ValueError("错误出现")
ValueError: 错误出现
继续执行

In this way, we can complete the exceptions are printed, can help us to analyze the error.

print_exc method error messages written to the log

traceback module There are two ways to print an exception, one is format_exc, the other is print_exc
both to do that: print_excthe method can not only print the error message in the console, but also to write error information to a file.
The above code to improve it:

import os
import time

def error_func():
    raise ValueError("错误出现")

if __name__ == '__main__':

    BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
    ERROR_LOG_PATH = os.path.join(BASE_DIR,'core','error_log.log')
    try:
        error_func()
    except ValueError:
        import traceback
        traceback.print_exc(file=open(ERROR_LOG_PATH,'a+'))

    time.sleep(1)
    print('继续执行')

We have additional ways whereabouts in writing the error log, so help us troubleshoot the error.

参考博客：https://www.cnblogs.com/alummox/p/7465197.html