[New-bugs-announce] [issue14436] SocketHandler sends obejcts while they cannot be unpickled on receiver's side

Zbigniew Kacprzak report at bugs.python.org
Thu Mar 29 12:03:11 CEST 2012

New submission from Zbigniew Kacprzak <zbika73 at gmail.com>:

I decided to use SocketHandler in multi-processes application.
Log server, sending data, logging simple strings - works fine.

The problem is with own classes (or external libraries).
Looks like SocketHandler creates pickles that cannot be unpickled then on receiver's side (it does not contain my own classes in PYTHONPATH).

The issue happens only when I use recommened way of passing parameters:

class LibInfo( object ):
  """Library info taken from xml"""
  def __init__(self, libName=None, xmlName=None, packName=None):
    self.libName = libName
    self.xmlName = xmlName
    self.packName = packName

  def __repr__(self):
    return "L=%s X=%s P=%s" % (self.libName,self.xmlName,self.packName)

myObj = LibInfo("1", "2", "3")
logging.info("Simple data: %s", myObj)

Traceback (most recent call last):
  File "/opt/python2.7/logging/handlers.py", line 563, in emit
    s = self.makePickle(record)
  File "/opt/python2.7/logging/handlers.py", line 533, in makePickle
    s = cPickle.dumps(record.__dict__, 1)
PicklingError: Can't pickle <class 'LibInfo'>: attribute lookup LibInfo failed

# these two lines work properly:
logging.info("Simple data: %s", str(myObj) )
logging.info("Simple data: %s" % myObj)

This would be not that critical: I could convert all passed parameters to strings. The issue is with external libraries. That I cannot control.

I think SocketHandler should make record with all parameters resolved to final string.

components: Library (Lib)
messages: 157019
nosy: Zbigniew.Kacprzak
priority: normal
severity: normal
status: open
title: SocketHandler sends obejcts while they cannot be unpickled on receiver's side
type: behavior
versions: Python 2.7

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