[ACCEPTED]-How to detect that Python code is being executed through the debugger?-debugging

Accepted answer
Score: 28

Python debuggers (as well as profilers and 8 coverage tools) use the sys.settrace function (in the 7 sys module) to register a callback that gets 6 called when interesting events happen.

If 5 you're using Python 2.6, you can call sys.gettrace() to 4 get the current trace callback function. If 3 it's not None then you can assume you should 2 be passing debug parameters to the JVM.

It's 1 not clear how you could do this pre 2.6.

Score: 17

Other alternative if you're using Pydev 1 that also works in a multithreading is:

    import pydevd
    DEBUGGING = True
except ImportError:
    DEBUGGING = False
Score: 15

A solution working with Python 2.4 (it should 5 work with any version superior to 2.1) and 4 Pydev:

import inspect

def isdebugging():
  for frame in inspect.stack():
    if frame[1].endswith("pydevd.py"):
      return True
  return False

The same should work with pdb by simply 3 replacing pydevd.py with pdb.py. As do3cc suggested, it 2 tries to find the debugger within the stack 1 of the caller.

Useful links:

Score: 10

Another way to do it hinges on how your 8 python interpreter is started. It requires 7 you start Python using -O for production 6 and with no -O for debugging. So it does 5 require an external discipline that might 4 be hard to maintain .. but then again it 3 might fit your processes perfectly.

From 2 the python docs (see "Built-in Constants" here or 1 here):

This constant is true if Python was not started with an -O option.

Usage would be something like:

if __debug__:
    print 'Python started without optimization'
Score: 7

If you're using Pydev, you can detect it 1 in such way:

import sys
if 'pydevd' in sys.modules: 
    print "Debugger"
    print "commandline"
Score: 1

From taking a quick look at the pdb docs 6 and source code, it doesn't look like there 5 is a built in way to do this. I suggest 4 that you set an environment variable that 3 indicates debugging is in progress and have 2 your application respond to that.

$ USING_PDB=1 pdb yourprog.py

Then in 1 yourprog.py:

import os
if os.environ.get('USING_PDB'):
    # debugging actions
Score: 1

You can try to peek into your stacktrace.


when 3 you try this in a debugger session:

import inspect

you will 2 get a list of framerecords and can peek 1 for any frames that refer to the pdb file.

Score: 0

I found a cleaner way to do it,

Just add 2 the following line in your manage.py

#!/usr/bin/env python
import os
import sys

if __debug__:

if __name__ == "__main__":

Then it would 1 automatically add it when you are debugging.

Score: 0

Since the original question doesn't specifically 2 call out Python2 - This is to confirm @babbageclunk's 1 suggested usage of sys also works in python3:

from sys import gettrace as sys_gettrace

DEBUG = sys_gettrace() is not None
print("debugger? %s" % DEBUG)
Score: 0

In my perllib, I use this check:

if 'pdb' in sys.modules:
    # We are being debugged

It assumes the 1 user doesn't otherwise import pdb

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