IOError: request data read error

Question

I seem to be getting an IOError: request data read error quite a lot when i'm doing an Ajax upload. For example out of every 5 file uploads it errors out on atleast 3.

Other people seem to have had the same issue. Eg.

• Django upload failing on request data read error
• Django file upload failing occasionally

Some other observations:

• It's definitely not my internet connection or a browser issue. Seems to be happening on all browsers chrome/FF/opera.

• I'm running django 1.1.1 Apache/2.2.14 (Ubuntu) mod_ssl/2.2.14 OpenSSL/0.9.8k mod_wsgi/2.8 Python/2.6.5 on Lucid.

• It is also not the file size. I can sometimes upload 1+ MB files but fail on 180 Kb files.

---

Traceback

Traceback (most recent call last):

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/core/handlers/base.py", line 98, in get_response
    response = middleware_method(request, e)

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/core/handlers/base.py", line 92, in get_response
    response = callback(request, *callback_args, **callback_kwargs)

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/contrib/auth/decorators.py", line 78, in __call__
    return self.view_func(request, *args, **kwargs)

  File "/home/ubuntu/webapps/anonymous_app/app/do_work/views/__init__.py", line 391, in some_form_ajax_upload
    f = request.FILES.get('file_upload')

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/core/handlers/wsgi.py", line 187, in _get_files
    self._load_post_and_files()

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/core/handlers/wsgi.py", line 137, in _load_post_and_files
    self._post, self._files = self.parse_file_upload(self.META, self.environ['wsgi.input'])

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/__init__.py", line 124, in parse_file_upload
    return parser.parse()

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 133, in parse
    for item_type, meta_data, field_stream in Parser(stream, self._boundary):

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 606, in __iter__
    for sub_stream in boundarystream:

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 420, in next
    return LazyStream(BoundaryIter(self._stream, self._boundary))

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 446, in __init__
    unused_char = self._stream.read(1)

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 299, in read
    out = ''.join(parts())

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 292, in parts
    chunk = self.next()

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 314, in next
    output = self._producer.next()

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 375, in next
    data = self.flo.read(self.chunk_size)

  File "/home/ubuntu/.virtualenvs/anonymous_app/lib/python2.6/site-packages/django/http/multipartparser.py", line 405, in read
    return self._file.read(num_bytes)

IOError: request data read error


<WSGIRequest
GET:<QueryDict: {}>,
POST:<could not parse>,
COOKIES:{'__utma': '168279989.1688771210.1285773436.1285773436.1285773436.1',
 '__utmb': '168279989.20.10.1285773436',
 '__utmc': '168279989',
 '__utmz': '168279989.1285773436.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)',
 'beta': 'True',
 'sessionid': 'b1ecf92f2bba13e1885d07803e10aa03',
 'timezone_offset': '-330'},
META:{'CONTENT_LENGTH': '188575',
 'CONTENT_TYPE': 'multipart/form-data; boundary=---------------------------57602381214905740261171925981',
 'DOCUMENT_ROOT': '/htdocs',
 'GATEWAY_INTERFACE': 'CGI/1.1',
 'HTTPS': '1',
 'HTTP_ACCEPT': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
 'HTTP_ACCEPT_CHARSET': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
 'HTTP_ACCEPT_ENCODING': 'gzip,deflate',
 'HTTP_ACCEPT_LANGUAGE': 'en-us,en;q=0.5',
 'HTTP_CONNECTION': 'keep-alive',
 'HTTP_COOKIE': 'beta=True; __utma=168279989.1688771210.1285773436.1285773436.1285773436.1; __utmb=168279989.20.10.1285773436; __utmc=168279989; __utmz=168279989.1285773436.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); sessionid=b1ecf92f2bba13e1885d07803e10aa03; timezone_offset=-330',
 'HTTP_HOST': 'xxxxxx.compute-1.amazonaws.com',
 'HTTP_KEEP_ALIVE': '115',
 'HTTP_REFERER': 'https://ec2-184-72-79-96.compute-1.amazonaws.com/do-my-somees/enter/some-documents/',
 'HTTP_USER_AGENT': 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.10) Gecko/20100915 Ubuntu/10.04 (lucid) Firefox/3.6.10',
 'PATH': '/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/X11R6/bin',
 'PATH_INFO': u'/do-my-somees/enter/some-documents/ajax-upload/Other-some-Document/',
 'PATH_TRANSLATED': '/home/ubuntu/webapps/anonymous_app/settings/apache/qa.wsgi.py/do-my-somees/enter/some-documents/ajax-upload/Other-some-Document/',
 'QUERY_STRING': '',
 'REMOTE_ADDR': '',
 'REMOTE_PORT': '15561',
 'REQUEST_METHOD': 'POST',
 'REQUEST_URI': '/do-my-somees/enter/some-documents/ajax-upload/Other-some-Document/',
 'SCRIPT_FILENAME': '/home/ubuntu/webapps/anonymous_app/settings/apache/qa.wsgi.py',
 'SCRIPT_NAME': u'',
 'SERVER_ADDR': '10.196.142.182',
 'SERVER_ADMIN': 'dev@anonymous_app.com',
 'SERVER_NAME': 'ec2-184-72-79-96.compute-1.amazonaws.com',
 'SERVER_PORT': '443',
 'SERVER_PROTOCOL': 'HTTP/1.1',
 'SERVER_SIGNATURE': '<address>Apache/2.2.14 (Ubuntu) Server at ec2-184-72-79-96.compute-1.amazonaws.com Port 443</address>\n',
 'SERVER_SOFTWARE': 'Apache/2.2.14 (Ubuntu)',
 'SSL_TLS_SNI': 'ec2-184-72-79-96.compute-1.amazonaws.com',
 'mod_wsgi.application_group': 'qa.anonymous_app.com|',
 'mod_wsgi.callable_object': 'application',
 'mod_wsgi.listener_host': '',
 'mod_wsgi.listener_port': '443',
 'mod_wsgi.process_group': '',
 'mod_wsgi.reload_mechanism': '0',
 'mod_wsgi.script_reloading': '1',
 'mod_wsgi.version': (2, 8),
 'wsgi.errors': <mod_wsgi.Log object at 0xb9456860>,
 'wsgi.file_wrapper': <built-in method file_wrapper of mod_wsgi.Adapter object at 0xb936a968>,
 'wsgi.input': <mod_wsgi.Input object at 0xb9720e30>,
 'wsgi.multiprocess': True,
 'wsgi.multithread': False,
 'wsgi.run_once': False,
 'wsgi.url_scheme': 'https',
 'wsgi.version': (1, 0)}>

Rotorua

Answer 1

I get this exception, too. In the Apache error logfile I see this:

[Wed Aug 17 08:30:45 2011] [error] [client 10.114.48.206] (70014)End of file found: mod_wsgi (pid=9722): Unable to get bucket brigade for request., referer: https://egs-work/modwork/beleg/188074/edit/
[Wed Aug 17 08:30:45 2011] [error] [client 10.114.48.206] mod_wsgi (pid=3572): Exception occurred processing WSGI script '/home/modwork_egs_p/modwork_egs/apache/django_wsgi.py'.
[Wed Aug 17 08:30:45 2011] [error] [client 10.114.48.206] IOError: failed to write data

Versions:

apache2-prefork-2.2.15-3.7.x86_64
apache2-mod_wsgi-3.3-1.8.x86_64 WSGIDaemonProcess with threads=1
mod_ssl/2.2.15
Linux egs-work 2.6.34.8-0.2-default #1 SMP 2011-04-06 18:11:26 +0200 x86_64 x86_64 x86_64 GNU/Linux
openSUSE 11.3 (x86_64)

First I was confused, because the last line "failed to write data" does not fit to the django code "load post data". But I guess that django wants to write an error page to the client. But the client has canceled the tcp connection. And now http 500 page can't be written to the client.

The client disconnected after sending the request, and before getting the response:

• The user closed the browser or navigated to an other page.
• The user pressed the reload button.

I have seen this only with POST-Requests (not GET). If POST is used, the webserver does read at least twice: First to get the headers, the second to get the data. The second read fails.

It is easy to reproduce:

Insert some code which waits before the first access to request.POST happens (be sure, that no middleware accesses request.POST before time.sleep()):

def edit(request):
    import time
    time.sleep(3)
    #.....

Now do a big POST (e.g. file upload). I don't know the apache buffer size. But 5 MB should be enough. When the browser shows the hourglass, browse to an other page. The browser will cancel the request and the exception should be in the logfile.

This is my Middleware, since I don't want to get the above traceback in our logfiles:

class HandleExceptionMiddleware:

    def process_exception(self, request, exception):
        if isinstance(exception, IOError) and 'request data read error' in unicode(exception):
            logging.info('%s %s: %s: Request was canceled by the client.' % (
                    request.build_absolute_uri(), request.user, exception))
            return HttpResponseServerError()

Colson

I'm having a difficult time trying to reproduce your middleware. I can comment out the if isinstance(...): condition, then cause cause an error in view code and it works swell. When I reproduce the IOError this middleware doesn't seem to do anything :\ – Adebayo

Update: what I've found is that the view code behaves as if the uploaded file was never given, and just responds with 200 showing a validation error message. The process_exception never fires. The suggestion here is that the correct approach is to filter in the logging layer: code.djangoproject.com/ticket/10046#comment:20 – Adebayo

Answer 2

as you might think, this is no django error.

see https://groups.google.com/group/django-users/browse_thread/thread/946936f69c012d96

have the error myself (but IE ajax requests only, no file upload, just post data).

will add an complete answer if i ever find out how to fix this.

Porphyrin

I have the exact same problem but I couldn't fix it yet. – Spiry

I also have the same problem. It is a very small ajax post request. Here a long thread in wsgi list: osdir.com/ml/django-developers/2011-02/msg00046.html – Sine

Hope you can give us some light. – Berne

@vinicius-massuchetto groups.google.com/forum/#!topic/boto-users/iWtvuECAcn4 – Rotorua

Answer 3

We were seeing this error on uploads to Django Rest Framework when the content-type header was incorrectly set to application/json. The post was actually multipart form data. The errors stopped when we removed the incorrect content-type header.

Lonesome

Answer 4

This happened to me recently. I was using django-ajax-uploader and small files were uploading successfully but large files e.g. 100MB were breaking in between with IOError: request data read error.

I checked my Apache configuration and found these setting RequestReadTimeout header=90 body=90 which means Allow 90 seconds to receive the request including the headers and 90 seconds for receiving the request body.

File is received in chunks at backend, which means if file size is big 90 seconds are not enough for some uploads. So how to determine the best value (seconds) for the requests?

So I have used this setting:

RequestReadTimeout header=90,MinRate=500 body=90,MinRate=500

Defining the MinRate solves the issue for me. The above setting states that:

Allow at least 90 seconds to receive the request body. If the client sends data, increase the timeout by 1 second for every 500 bytes received

As the client is sending data continuously (ajax upload) it makes sense to automatically increase the timeout if data is received. More information/variations about the RequestReadTimeout can be found here.

Sympathetic

This is actually a pretty good answer, in my case the error was when on Django I was trying to the read the length of the request body with len(request.body) – Ojeda

Answer 5

Taking this from the thread: Getting rid of Django IOErrors

Extending the possible solution by @dlowe for Django 1.3, to suppress the IOError in concern, we can write the full working example as:

settings.py

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'filters': {
        'supress_unreadable_post': {
            '()': 'common.logging.SuppressUnreadablePost',
        }
    },
    'handlers': {
        'mail_admins': {
            'level': 'ERROR',
            'class': 'django.utils.log.AdminEmailHandler',
            'filters': ['supress_unreadable_post'],
        }
    },
    'loggers': {
        'django.request': {
            'handlers': ['mail_admins'],
            'level': 'ERROR',
            'propagate': True,
        },
    }
}

common/logging.py

import sys, traceback

class SuppressUnreadablePost(object):
    def filter(self, record):
        _, exception, tb = sys.exc_info()
        if isinstance(exception, IOError):
            for _, _, function, _ in traceback.extract_tb(tb):
                if function == '_get_raw_post_data':
                    return False
        return True

Ecotone

Answer 6

This issue has been open for a long time and has something to do with lower level libraries. I was using boto to upload files to S3. A temporary stopgap I found was to add an explicit HTTP socket timeout of 10 seconds. I haven't seen the error after that. You can do that by creating a boto config on the server:

#/etc/boto.cfg 
[Boto]
http_socket_timeout=10

Also make sure the file is readable by the app. See my original post on google group: https://groups.google.com/forum/#!topic/boto-users/iWtvuECAcn4

Rotorua

Answer 7

I got this error when validating my site on a Win8 machine with IE 10. When I tested file upload from IE the upload was stucked on 1% and after +/- 1 minute I got the error on server logs. I just discovered that it was caused by the TrendMicro complement. Once I disabled the complement the upload occurred without any problem.

Griz