Amazon EC2 error IOError Input / Output every 6 or 12 Hours

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Amazon EC2 error IOError Input / Output every 6 or 12 Hours

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#1 by (1 votes)

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When I put my project in Amazon EC2, I happened to interact with my application in a moment the error of

errno 5 input/output error django

I found this ticket reported

In my console it appeared to me that my server required to restart, and when I did, and I started my application again (gunicorn and nginx) everything was magically arranged.

This error appeared yesterday and today again. The traceback is this:

Environment:

Request Method: GET
Request URL: http://localhost:8000/accounts/profile/

Django Version: 1.9
Python Version: 3.4.3
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'crispy_forms',
 'django_extensions',
 'storages',
 'userprofile']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback:

File "/home/ubuntu/.virtualenvs/nrb_dev/lib/python3.4/site-packages/django/core/handlers/base.py" in get_response
  149.                     response = self.process_exception_by_middleware(e, request)

File "/home/ubuntu/.virtualenvs/nrb_dev/lib/python3.4/site-packages/django/core/handlers/base.py" in get_response
  147.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/home/ubuntu/.virtualenvs/nrb_dev/lib/python3.4/site-packages/django/views/generic/base.py" in view
  68.             return self.dispatch(request, *args, **kwargs)

File "/home/ubuntu/.virtualenvs/nrb_dev/lib/python3.4/site-packages/django/utils/decorators.py" in _wrapper
  67.             return bound_func(*args, **kwargs)

File "/home/ubuntu/.virtualenvs/nrb_dev/lib/python3.4/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
  23.                 return view_func(request, *args, **kwargs)

File "/home/ubuntu/.virtualenvs/nrb_dev/lib/python3.4/site-packages/django/utils/decorators.py" in bound_func
  63.                 return func.__get__(self, type(self))(*args2, **kwargs2)

File "/home/ubuntu/workspace/neurorehabilitation-system/userprofile/mixins.py" in dispatch
  7.         return super(LoginRequiredMixin, self).dispatch(request, *args, **kwargs)

File "/home/ubuntu/.virtualenvs/nrb_dev/lib/python3.4/site-packages/django/views/generic/base.py" in dispatch
  88.         return handler(request, *args, **kwargs)

File "/home/ubuntu/.virtualenvs/nrb_dev/lib/python3.4/site-packages/django/views/generic/base.py" in get
  157.         context = self.get_context_data(**kwargs)

File "/home/ubuntu/workspace/neurorehabilitation-system/userprofile/views.py" in get_context_data
  50.             print (user.is_physiotherapist)

Exception Type: OSError at /accounts/profile/
Exception Value: [Errno 5] Input/output error

At the end of line 50, a function of my get_context_data() is referenced, which belongs to a class-based view that inherits from TemplateView

I would dare to think that this has nothing to do with the error, given that in my development environment nothing happened.

File "/home/ubuntu/workspace/neurorehabilitation-system/userprofile/views.py" in get_context_data
  50.             print (user.is_physiotherapist)

But at the beginning if it matches what the ticket I share describes.

When a bug is declared invalid in Django, what does that mean? If I go by logic, one would think that the bug is totally obsolete or that it has no validity ... But I do not know what to think.

Is it possible that there is a problem at the IaaS infrastructure level of EC2 with Django (which I do not think we are talking about giant companies) or rather would it be my application?

python django ec2

asked by bgarcial 06.01.2016 в 22:48

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1 answer

problems with 'cat' in bash How to know which mouse button was pressed

score 1 · Accepted Answer

I have been detailing my code and I have to say that the cause of this input / output problem was there.

I made two rookie mistakes: (

I have a statement print in production

In the traceback that I showed above in my question, in my function get_context_data() I have this:

File "/home/ubuntu/workspace/neurorehabilitation-system/userprofile/views.py" in get_context_data
  50.             print (user.is_physiotherapist)

This function get_context_data() is executed every time my user logs in the system, it is possible that every time the print (user.is_physiotherapist) is executed, this process tries to write something to the stdout file of my machine in EC2, although it is something that I do not quite understand or size at all

I have deleted this print statement, I made commit and push to my repository, and on my server I recovered those changes and rebooted my gunicorn server and everything worked perfectly.

I have DEBUG = True in production

For my settings I have the following file hierarchy:

settings/
    base.py --- SIN DEBUG
    development.py --- DEBUG=True
    testing.py --- DEBUG=True
    production.py --- DEBUG=False
    staging.py --- DEBUG=False

All files ( development.py, testing.py, production.py, staging.py ) inherit from base.py

But I do not know how to make my machine on EC2, which is my production server, take base.py and then execute production.py and overwrite the DEBUG to False

In this post you set the value of DEBUG ( True or False ) according to the hostname of the machine where my Django application runs.

In my case in my instance E2, this is the value of my hostname

(nrb_dev)ubuntu@ip-172-31-27-249:~$ python
Python 3.4.3 (default, Oct 14 2015, 20:28:29) 
[GCC 4.8.4] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import socket
>>> a=socket.gethostname()
>>> a
'ip-172-31-27-249'
>>> 
>>> if a != 'ip-172-31-27-249':
...     DEBUG = print ('Caleno juiciocito')
... 
>>> DEBUG
True
>>>

This means that in my file base.py I would place:

import socket

if socket.gethostname() == 'ip-172-31-27-249':
    DEBUG = False
else:
    DEBUG = True

My concern is that I am "hardcodeando" the hostname of my production machine so I am introducing a point that must be modified manually when the production machine to be used is not the same.

Is this a good practice even though it works? I would think not, but any contribution in this sense is welcome.

Because another option I have is to set the value of the environment variable of DJANGO_SETTINGS_MODULE

In my case, I am using virtualenvwrapper and I have two virtual environments:

nrb_dev for development where I have a hook in $VIRTUAL_ENV/bin/postactivate like this:

export DJANGO_SETTINGS_MODULE="neurorehabilitation.settings.development"

In the same way, in my virtual environment nrb_test I have this hook

export DJANGO_SETTINGS_MODULE="neurorehabilitation.settings.testing"

This means that in my production machine I simply change this hook in $VIRTUAL_ENV/bin/postactivate like this:

export DJANGO_SETTINGS_MODULE="neurorehabilitation.settings.production"

And when doing the test (I printed the value of DEBUG temporarily in my file settings/production.py ) I see that DEBUG is set to False

(nrb_dev)ubuntu@ip-172-31-27-249:~/workspace/neurorehabilitation-system$ gunicorn -c neurorehabilitation/gunicorn_config.py neurorehabilitation.wsgi 
[2016-01-08 00:26:15 +0000] [6691] [INFO] Starting gunicorn 19.4.5
[2016-01-08 00:26:15 +0000] [6691] [INFO] Listening at: http://127.0.0.1:8000 (6691)
[2016-01-08 00:26:15 +0000] [6691] [INFO] Using worker: sync
[2016-01-08 00:26:15 +0000] [6694] [INFO] Booting worker with pid: 6694
False
^C[2016-01-08 00:26:19 +0000] [6691] [INFO] Handling signal: int

I think that this second option to modify the environment variable of DJANGO_SETTINGS_MODULE on my production machine is better, but any input or consideration is welcome.

Additional notes

If I wanted to keep an event log in my application, I can explore Django logging functionality

I need to explore the supervisor service to better manage the WSGI server of gunicorn . Some interesting resources in this regard are:

How to install and manage supervisor in Ubuntu and Debian

Setting up Django with Nginx, Gunicorn, virtualenv, supervisor and PostgreSQL