x.py

import traceback
import os
orig_close = os.close
def patched_close(*args, **kwargs):
        print '----------------------------'
        print 'os.close!',args,kwargs
        traceback.print_stack()
        print
        return orig_close(*args, **kwargs)
os.close = patched_close


import socket,traceback
orig_socket = socket.socket

class wrap_socket(orig_socket):
        def __init__(self, *args, **kwargs):
                orig_socket.__init__(self, *args, **kwargs)
                #print '------------------------------'
                #traceback.print_stack()
                print '--> new sock', self.fileno()
                print

        def close(self):
                print '--> before close sock', self.fileno()
                #traceback.print_stack()
                orig_socket.close(self)
                print '--> after close sock'

socket.socket = wrap_socket

import requests
import subprocess


pid = os.getpid()
reqsess = requests.session()
try:
        r = reqsess.get(r'http://www.mouser.com/Search/Refine.aspx?Keyword=test')
        d = r.text
finally:
        reqsess.close()

import os

print 'done, calling lsof'

subprocess.call("lsof -p%d -a -iTCP" % (pid,), shell=True)
print 'done'