"django.request" logging breaks "logging.handlers.SocketHandler"

[direx]

When setting up logging with Python's default SocketHandler then the log messages produced by django.request cause an exception in the logging system. This happens everywhere where Django passes an extra={'request': request} dictionary to log messages. The reason for this is that the request object cannot be pickled.

Steps to reproduce (example):

1. ./manage.py startproject
2. Add this logging config in settings:

   LOGGING = {    
       'version': 1,
       'disable_existing_loggers': False,
       'handlers': {
           'socket_handler': {
               'class': 'logging.handlers.SocketHandler',
               'host': '127.0.0.1',
               'port': 9020,
           }   
       },  
       'loggers': {
           'django.request': {
               'handlers': ['socket_handler'],
               'level': 'INFO',
               'propagate': False,
           },  
       }   
   }
   

3. ./manage.py migrate
4. ./manage.py runserver
5. wget http://127.0.0.1:8000/invalid -O /dev//null

The exception is this one:

--- Logging error ---
Traceback (most recent call last):
  File "/usr/lib/python3.6/logging/handlers.py", line 633, in emit
    s = self.makePickle(record)
  File "/usr/lib/python3.6/logging/handlers.py", line 605, in makePickle
    s = pickle.dumps(d, 1)
  File "/usr/lib/python3.6/copyreg.py", line 65, in _reduce_ex
    raise TypeError("can't pickle %s objects" % base.__name__)
TypeError: can't pickle BufferedReader objects
Call stack:
  File "/usr/lib/python3.6/threading.py", line 884, in _bootstrap
    self._bootstrap_inner()
  File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.6/threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib/python3.6/socketserver.py", line 639, in process_request_thread
    self.finish_request(request, client_address)
  File "/usr/lib/python3.6/socketserver.py", line 361, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/usr/lib/python3.6/socketserver.py", line 696, in __init__
    self.handle()
  File "/home/direx/virtualenv/django-2.0/lib/python3.6/site-packages/django/core/servers/basehttp.py", line 154, in handle
    handler.run(self.server.get_app())
  File "/usr/lib/python3.6/wsgiref/handlers.py", line 137, in run
    self.result = application(self.environ, self.start_response)
  File "/home/direx/virtualenv/django-2.0/lib/python3.6/site-packages/django/contrib/staticfiles/handlers.py", line 66, in __call__
    return self.application(environ, start_response)
  File "/home/direx/virtualenv/django-2.0/lib/python3.6/site-packages/django/core/handlers/wsgi.py", line 146, in __call__
    response = self.get_response(request)
  File "/home/direx/virtualenv/django-2.0/lib/python3.6/site-packages/django/core/handlers/base.py", line 93, in get_response
    extra={'status_code': 404, 'request': request},
Message: 'Not Found: %s'
Arguments: ('/invalid',)

Of course these steps are only an example. This bug does not only apply to 404 errors, but also to CSRF verfication errors for instance. In fact all places where the request object is passed in as an extra logger argument.

I see a few possible solutions for this issue:

1. Remove the request object from the extra log message dict. Right now I am not even sure why this is required.
2. Make the entire request object pickleable (probably not an easy task)
3. Pass in a reduced (pickable) version of the request object in the extra dict
4. Ship a compatible version of SocketHandler

BTW: socket logging is explicitly mentioned in the Django docs:

The handler is the engine that determines what happens to each message in a logger. It describes a particular logging behavior, such as writing a message to the screen, to a file, or to a network socket.

This bug also applies to older Django versions.