Question

I’m using Twister to build a server. I am also maintaining a server error log. The issue is that if I let an exception run all the way up the stack, it’ll crash the current connection and disconnect the user, so obviously I attach a bare except to grab everything else.

Once I’ve caught something, is there a way to get the traceback as a string so that I can store it somewhere/print it myself without raising it and letting Python print it for me once the program crashes?

Answer 1

The traceback module contains some helper functions for printing and inspecting the traceback (for exameble, traceback.print_tb ) – but the important thing is that the traceback information itself is stored in a “interpreter global” variable – sys.exc_traceback, on the module sys.

Quoting from:

http://docs.python.org/reference/compound_stmts.html#try

Before an except clause’s suite is executed, details about the
exception are assigned to three variables in the sys module:
sys.exc_type receives the object identifying the exception;
sys.exc_value receives the exception’s parameter; sys.exc_traceback
receives a traceback object…

You can pass the sys.exc_traceback object as a parameter to traceback.print_tb to have the traceback printed to stdout within the except clause.