Debugging in Python django

Debugging in Python django using pdb

Debugger Module Contents

The pdb module contains the debugger. pdb contains one class, Pdb, which inherits from bdb.Bdb. The debugger documentation mentions six functions, which create an interactive debugging session:

pdb.run(statement[, globals[, locals]])
pdb.runeval(expression[, globals[, locals]])
pdb.runcall(function[, argument, ...])
pdb.set_trace()
pdb.post_mortem(traceback)
pdb.pm()

All six functions provide a slightly different mechanism for dropping a user into the debugger.

pdb.run(statement[, globals[, locals]])

pdb.run() executes the string statement under the debugger's control. Global and local dictionaries are optional parameters:

#!/usr/bin/env python

import pdb

def test_debugger(some_int):
   print "start some_int>>", some_int
   return_int = 10 / some_int
   print "end some_int>>", some_int
   return return_int

if __name__ == "__main__":
   pdb.run("test_debugger(0)")

pdb.runeval(expression[, globals[, locals]])

pdb.runeval() is identical to pdb.run(), except that pdb.runeval() returns the value of the evaluated string expression:

#!/usr/bin/env python

import pdb

def test_debugger(some_int):
   print "start some_int>>", some_int
   return_int = 10 / some_int
   print "end some_int>>", some_int
   return return_int

if __name__ == "__main__":
   pdb.runeval("test_debugger(0)")

pdb.runcall(function[, argument, ...])

pdb.runcall() calls the specified function and passes any specified arguments to it:

#!/usr/bin/env python

import pdb

def test_debugger(some_int):
   print "start some_int>>", some_int
   return_int = 10 / some_int
   print "end some_int>>", some_int
   return return_int

if __name__ == "__main__":
   pdb.runcall(test_debugger, 0)

pdb.set_trace()

pdb.set_trace() drops the code into the debugger when execution hits it:

#!/usr/bin/env python

import pdb

def test_debugger(some_int):
   pdb.set_trace()
   print "start some_int>>", some_int
   return_int = 10 / some_int
   print "end some_int>>", some_int
   return return_int

if __name__ == "__main__":
   test_debugger(0)

pdb.post_mortem(traceback)

pdb.post_mortem() performs postmortem debugging of the specified traceback:

#!/usr/bin/env python

import pdb

def test_debugger(some_int):
   print "start some_int>>", some_int
   return_int = 10 / some_int
   print "end some_int>>", some_int
   return return_int

if __name__ == "__main__":
   try:
       test_debugger(0)
   except:
       import sys
       tb = sys.exc_info()[2]
       pdb.post_mortem(tb)

pdb.pm()

pdb.pm() performs postmortem debugging of the traceback contained in sys.last_traceback:

#!/usr/bin/env python

import pdb
import sys

def test_debugger(some_int):
   print "start some_int>>", some_int
   return_int = 10 / some_int
   print "end some_int>>", some_int
   return return_int

def do_debugger(type, value, tb):
   pdb.pm()

if __name__ == "__main__":
   sys.excepthook = do_debugger
   test_debugger(0)

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