Can't pickle <type 'function'>: attribute lookup __builtin__.function failed
django, pickle, python
Solution
Where can I print out the object that is giving issues from this error so that it will appear in the Django error page?
The short answer - without recompiling `cPickle`, you can't.
Longer answer: This is the piece of code that raises the exception:
root $ grep -Hra "attribute lookup" /usr/lib64/ 2>/dev/null | grep -a failed
/usr/lib64/python2.7/lib-dynload/cPickle.so:H�H���P0H�5zM H�=1��M��H��H�ZM �����H�=�1�H���M��H��H��M �����H�4M H�5~H���H���������H�M H�5tH���H���������H��L H�5�H���qH�����d���H�M H�5NH���SH�����F���H�dM H�5bH���5H�����(���H�=X1��O��H�HC H�5I H�=U1�A��H��L �vH��H��I�������H���RK��H�=.H����J��H�5$H��H��H�D$�G��H�D$H��tH�H��H��H��gH�DL�ttH�qH�5nH�=kH��1��XK��H�5bH��H��I����F��H�5\L��H���F��H��tH�EH��H��H�E��M�������I�$H��H��I�$�t���I�DL���P0�d���f�H�EH��H��H�E�F���H�H���P0�7���@H�|$H��P0�����H�H���P0�����H�H���P0�k�����UH��SH�H�H: H���tH�;: H���H�H���u�H�[��H��M��H��attribute deletion is not supportedunsupported pickle protocol: %dargument must have 'read' and 'readline' attributespickle protocol %d asked for; the highest available protocol is %dargument must have 'write' attributeGlobal and instance pickles are not supported.Attempt to getvalue() a non-list-based picklerUnexpected data in internal listBINSTRING pickle has negative byte countno int where int expected in memoCan't pickle %s: import of module %s failedCan't pickle %s: attribute lookup %s.%s failedCan't pickle %s: it's not the same object as %s.%sCan't pickle %s: extension code %s isn't an integerCan't pickle %s: extension code %ld is out of rangecould not convert string to intLONG pickle has negative byte countcould not convert string to floatBINUNICODE pickle has negative byte countunregistered extension code %ld_inverted_registry[%ld] isn't a 2-tuple of stringsA load persistent id instruction was encountered,
If you look close enough, there's a piece that says
Can't pickle %s: attribute lookup %s.%s failed
Now, if you download Python sources, you can easily find the piece of code responsible for raising the exception in the function `static int save_global(Picklerobject *self, PyObject *args, PyObject *name)` of `./Modules/cPickle.c`:
klass = PyObject_GetAttrString(mod, name_str);
if (klass == NULL) {
cPickle_ErrFormat(PicklingError,
"Can't pickle %s: attribute lookup %s.%s "
"failed",
"OSS", args, module, global_name);
goto finally;
}
So, the best you can do to debug this error is to format the string differently (probably providing `PyString_AS_STRING((PyStringObject *)name)`, recompile and install the modified version of Python.
Yeah, I know that's too bad. I just had the same problem myself.
Problem
I'm receiving this error in my Django application, however, it only happens once a day or less and it's proving extremely difficult to debug. ``` Environment: Request Method: POST Django Version: 1.3.1 Python Version: 2.6.6 Installed Applications: ['django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.sites', 'fimedlabs', 'data', 'djcelery'] Installed Middleware: ('django.middleware.common.CommonMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'fimedlabs.auth.userMiddleWare') Traceback: File "/usr/local/lib/python2.6/dist-packages/django/core/handlers/base.py" in get_response 178. response = middleware_method(request, response) File "/usr/local/lib/python2.6/dist-packages/django/contrib/sessions/middleware.py" in process_response 36. request.session.save() File "/usr/local/lib/python2.6/dist-packages/django/contrib/sessions/backends/db.py" in save 57. session_data = self.encode(self._get_session(no_load=must_create)), File "/usr/local/lib/python2.6/dist-packages/django/contrib/sessions/backends/base.py" in encode 93. pickled = pickle.dumps(session_dict, pickle.HIGHEST_PROTOCOL) Exception Type: PicklingError at / Exception Value: Can't pickle <type 'function'>: attribute lookup __builtin__.function failed ``` I've tried the answer to this: How to tell for which object attribute pickle fails? by adding self to the actual error to see if that would print anything in the Django error to no avail. Where can I print out the object that is giving issues from this error so that it will appear in the Django error page? Thanks! ~Matt EDIT: The only object I'm storing in the cache, is a user object with the code: ``` class user(object): username = str() userid = uuid.UUID(int=0) client = models.Client() clientid = uuid.UUID(int=0) clientname = '' data = models.User() accesslevel = models.AccessLevel() active = False client_active = False isFimed = False isFimedAdmin = False isClientAdmin = False isFimedManager = False mysettingsform = None viewingas = False menu = [] _exists = False _authenticated = False def __str__(self): return str(self.__dict__.copy()) def __getstate__(self): return self.__dict__.copy() def __setstate__(self, dict): self.__dict__ = dict def __init__(self, username=None): if username: self.initialize(username) def initialize(self, username): self.username = username model = models.User.objects.filter(username=username).all() if len(model) == 1: model = model[0] self.data = model self._exists = True self.userid = self.data.id self.active = self.data.active self.isFimed = self.data.isFimed() self.isFimedAdmin = self.data.isFimedAdmin() self.isClientAdmin = self.data.isClientAdmin() self.isFimedManager = self.data.isFimedManager() self.mysettingsform = UserFormSelf(initial={"id":model.id, "username":model.username, "name":model.name, "email":model.email, "phone":model.phone}) self.accesslevel = models.AccessLevel.objects.filter(id=self.data.accesslevel_id)[:1][0].level cli = self.data.client self.client = cli self.clientid = cli.id self.clientname = cli.name if cli.active: self.client_active = True model.lastlogin = datetime.datetime.now() model.save() self.menu = getMenu(self.data) else: self._exists = False def authenticate(self, password): self._authenticated = False if (self.active == False or self.client_active == False): return False if self._exists: import hashlib hash = hashlib.md5('%s%s' % (str(password), self.data.pwsalt)).hexdigest() if hash == self.data.pwhash: self._authenticated = True return True return False def updateUser(self): self.initialize(models.User.objects.filter(id=self.userid).get().username) def mkContext(self): c = Context() c['menu'] = self.menu c['user'] = self c['language'] = language c['colors'] = colors c["isFimed"] = self.isFimed c["isFimedAdmin"] = self.isFimedAdmin c["isClientAdmin"] = self.isClientAdmin c["isFimedManager"] = self.isFimedManager c["mysettingsform"] = self.mysettingsform return c ``` EDIT: WSGI file after Werkzeug: ``` import django.core.handlers.wsgi djangoapplication = django.core.handlers.wsgi.WSGIHandler() def application(environ, start_response): if 'SCRIPT_NAME' in environ: del environ['SCRIPT_NAME'] return djangoapplication(environ, start_response) # The following lines enable the werkzeug debugger import django.views.debug def null_technical_500_response(request, exc_type, exc_value, tb): raise exc_type, exc_value, tb django.views.debug.technical_500_response = null_technical_500_response from werkzeug.debug import DebuggedApplication application = DebuggedApplication(application, evalex=True) ```