print python stack trace without exception being raised

python debugging stack-trace
Claudiu picture Claudiu · Oct 13, 2010 · Viewed 24.5k times · Source

Something is happening with one of my class's instance variables. I want to make the variable a property, and whenever it is accessed I want to print out the stack trace of all the code leading up to that point, so I can see where it's being messed with. How do I print out the stack trace when no exception has been raised? I know if there is an exception I can do something like traceback.format_tb(sys.exc_info()[2]).

Also what might be useful is to print only the last 3-4 levels, since the first few are probably not going to be that interesting.

Answer

user395760 picture user395760 · Oct 13, 2010

traceback.print_stack():

>>> def f():
...   def g():
...     traceback.print_stack()
...   g()
...
>>> f()
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 4, in f
  File "<stdin>", line 3, in g

Edit: You can also use extract_stack, take a slice (e.g. stack[5:] for exclude the first 5 levels) and use format_list to get a print-ready stacktrace ('\n'.join(traceback.format_list(...)))

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