Question

When I get a runtime exception from the standard library, it’s almost always a problem in my code and not in the library code. Is there a way to truncate the exception stack trace so that it doesn’t show the guts of the library package?

For example, I would like to get this:

Traceback (most recent call last):
  File "./lmd3-mkhead.py", line 71, in <module>
    main()
  File "./lmd3-mkhead.py", line 66, in main
    create()
  File "./lmd3-mkhead.py", line 41, in create
    headver1[depotFile]=rev
TypeError: Data values must be of type string or None.

and not this:

Traceback (most recent call last):
  File "./lmd3-mkhead.py", line 71, in <module>
    main()
  File "./lmd3-mkhead.py", line 66, in main
    create()
  File "./lmd3-mkhead.py", line 41, in create
    headver1[depotFile]=rev
  File "/usr/anim/modsquad/oses/fc11/lib/python2.6/bsddb/__init__.py", line 276, in __setitem__
    _DeadlockWrap(wrapF)  # self.db[key] = value
  File "/usr/anim/modsquad/oses/fc11/lib/python2.6/bsddb/dbutils.py", line 68, in DeadlockWrap
    return function(*_args, **_kwargs)
  File "/usr/anim/modsquad/oses/fc11/lib/python2.6/bsddb/__init__.py", line 275, in wrapF
    self.db[key] = value
TypeError: Data values must be of type string or None.

update: added an answer with the code, thanks to the pointer from Alex.

Answer 1

Thanks to the pointer from Alex, here’s teh codez:

def trimmedexceptions(type, value, tb, pylibdir=None, lev=None):
    """trim system packages from the exception printout"""
    if pylibdir is None:
        import traceback, distutils.sysconfig
        pylibdir = distutils.sysconfig.get_python_lib(1,1)
        nlev = trimmedexceptions(type, value, tb, pylibdir, 0)
        traceback.print_exception(type, value, tb, nlev)
    else:
        fn = tb.tb_frame.f_code.co_filename
        if tb.tb_next is None or fn.startswith(pylibdir):
            return lev
        else:
            return trimmedexceptions(type, value, tb.tb_next, pylibdir, lev+1)

import sys
sys.excepthook=trimmedexceptions

# --- test code ---

def f1(): f2()
def f2(): f3()
def f3():
    import xmlrpclib
    proxy = xmlrpclib.ServerProxy('http://nosuchserver')
    proxy.f()

f1()

Which yields this stack trace:

Traceback (most recent call last):
  File "./tsttraceback.py", line 47, in <module>
    f1()
  File "./tsttraceback.py", line 40, in f1
    def f1(): f2()
  File "./tsttraceback.py", line 41, in f2
    def f2(): f3()
  File "./tsttraceback.py", line 45, in f3
    proxy.f()
gaierror: [Errno -2] Name or service not known