Virtualenv package issue on Heroku deploy (Django app) - django

Question

I have deployed a Django project to Heroku, but I've run into an issue: there is a package, that's inside the virtualenv folder, that gives me an error.
This is the traceback
Environment:
Request Method: POST
Request URL: https://pin-a-voyage.herokuapp.com/login/
Django Version: 1.8
Python Version: 2.7.6
Installed Applications:
('django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'blog',
'custom_user',
'django_markdown',
'parsley')
Installed Middleware:
('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',
'django.middleware.security.SecurityMiddleware',
'whitenoise.middleware.WhiteNoiseMiddleware')
Traceback:
File "/app/.heroku/python/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
132. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/app/blog/views.py" in login
147. auth_login(request, user)
File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/auth/__init__.py" in login
117. user_logged_in.send(sender=user.__class__, request=request, user=user)
File "/app/.heroku/python/lib/python2.7/site-packages/django/dispatch/dispatcher.py" in send
201. response = receiver(signal=self, sender=sender, **named)
File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/auth/models.py" in update_last_login
26. user.save(update_fields=['last_login'])
File "/app/custom_user/models.py" in save
62. new_image = resizeimage.resize_width(pil_image_obj, 300)
File "/app/.heroku/python/lib/python2.7/site-packages/resizeimage/resizeimage.py" in wrapper
31. validator(image, size)
File "/app/.heroku/python/lib/python2.7/site-packages/resizeimage/resizeimage.py" in _width_is_big_enough
47. raise ImageSizeError(image.size[0], width)
Exception Type: ImageSizeError at /login/
Exception Value: 'Image is too small, Image size : 300, Required size : 300'
In a nutshell: I upload a profile pic, but I run into this error, because I have modified the package on the virtualenv folder, but the virtualenv folder isn't pushed to Heroku.
Since the virtualenv folder has to be put in .gitignore when deploying to Heroku (isn't it?), how can I avoid this problem?

Answer 1

If you need to make local edits to a package ( but consider instead contributing or forking a new version ), then you may want to copy that package into your Django project and use it as if you would have written it yourself. I.e. As a regular Django app in your project.

Answer 2

In most cases one should not edit files in a virtual environment. This is because virtual environment holds packages installed with pip only in the local system. However the developer can edit code of the installed app if requirement cannot by achieved by using the options/attributes provided with the package.
You can push customized code of your installed app and can use it in your production environment by using overriding file with custom code. See reusable apps for an example.
First make sure updated requirements.txt is pushed to your production environment. From the stack trace /site-packages/resizeimage/ is causing you issues. If you are using PIL update requirements.txt to include pil and install PIL in your heroku server too.
then override the necessary files of your package. To do this you can create a directory with same name as of the pip package and then create a file with the same name of the one you have to edit. After this push this directory.