traceback — Print or retrieve a stack trace

This module provides a standard interface to extract, format and print stack traces of Python programs. It exactly mimics the behavior of the Python interpreter when it prints a stack trace. This is incredibly useful when you want to catch an exception, log its full trace, but NOT crash your program.

import traceback

Printing Tracebacks without Crashing

Normally, uncaught exceptions crash the program and print a traceback to the console. If you wrap code in a try...except block to prevent a crash, the traceback is usually lost. The traceback module fixes this:

import traceback

def risky_function():
    return 1 / 0

try:
    risky_function()
except Exception as e:
    print("Oh no, an error occurred, but the program continues!")
    
    # 1. Print the RED traceback to the console (sys.stderr)
    traceback.print_exc()

print("Program is still running here...")

Extracting Tracebacks as Strings

If you want to save the traceback to a database, send it via email to a developer, or log it securely to a file (instead of just printing it), you can format it into a standard string.

import traceback
import sys

try:
    risky_function()
except Exception as e:
    # 2. Get the traceback as a massive string
    error_string = traceback.format_exc()
    
    # Now you can save it anywhere!
    with open('error_log.txt', 'a') as f:
        f.write("\n--- ERROR ---\n")
        f.write(error_string)

API Reference

Important Functions