Google App Engine, Django, CloudSQL and Images - django

Currently porting some Django projects over to Google App Engine.
I am using Python 2.7, Django 1.4 and Google CloudSQL.
The problem I have is with an Admin driven Gallery.
Handling image upload seems to be a problem, using ImageField I am getting an erorr on mkdir command as GAE wont allow a local write.
I am a little stuck and solutions seem quite confused, I am using CloudSQL due to its compatibility with the old MySQL databases that ran the sites previously.
How can I get the gallery back up and running without local storage? I have been researching use of GAE blobstore, but posts seem quite varied and unhelpful.
Cheers
Kevin

You'll have to rewrite ImageField to use the BlobStore instead of files.
A quick google search suggests someone might have already done this:
http://blog.uysrc.com/2011/02/12/image-uploads-working-with-models-imagefield/

Related

How to load images on Heroku (Django deployed app)

I've just recently deployed my Django application using heroku, and have an issue where the profile pictures in my blog website don't save (ends up being an image that never loads).
Is there any way I can solve this (and if so, without using Amazon S3)?
I want to avoid Amazon S3 if possible.
Is there anyway or alternatives to implement images into my Heroku website?
I've used Cloudinary for a django blog on heroku. The api allows you to upload and display images quite easily.
You will have to serve the images using static files. Also, you will need to install WhiteNoise, which will serve the static files on Heroku. For the short-term this should be fine, however, for the long term, it is recommended that you use a cloud-based service.
This link is the main guide:
https://github.com/codingforentrepreneurs/Guides/blob/master/all/Heroku_Django_Deployment_Guide.md
I would recommend going through the references also.
These would be the references:
1) http://whitenoise.evans.io/en/stable/django.html
2) https://docs.djangoproject.com/en/3.0/howto/static-files/
3) https://docs.djangoproject.com/en/3.0/ref/templates/builtins/#std:templatetag-static
I ran into the same problem you ran into. Following the steps in the guide and references worked well for me.

Django, appengine and Django-nonrel

I want to create a web app using Django 1.5 or 1.6 using appEngine. I have read about as I have to do it and I have read about Django-nonrel which is very usefull to avoid the issues related with non-relational Database. Unfortunately I have read about the origininal creators project and they have left the project:
GoodBye
However I have seen new avaiables versions of Django AppEngine wich allow to use the 1.4 and 1.5 versions of Django
https://groups.google.com/forum/#!topic/django-non-relational/I06693ZPeME
After I have read every text I am a mess, do anyone redomended me use last version of django non-rel? can I use other framework? don't I use the last verion of Django?
Thank you.
I have developed a fairly complex web app using "normal" Django, not the non-rel flavour. For database storage I use Google Cloud SQL which is basically MySQL in the cloud. It works pretty good. There are some points to consider:
Google Cloud SQL has no "free plan", so it will incur a cost on your project.
Normal Django for GAE is currently at version 1.4 and lags a bit behind development which is if memory serves me right at 1.6. There is a version 1.5 of Django that comes with the GAE SDK but I did not get that work (I did not put any particular effort in it, just changed the Django version in my app.yaml file and it crashed).
As for the first bullet, there's now also a comparable product available from Amazon. I have not yet looked into it (I believe they do offer a free plan which might be interesting to try out), nor compared prices but that might be an alternative should Google Cloud SQL be too expensive. My yearly cost for Google Cloud SQL are between £150 and £200 which is not too bad.
My reason for choosing normal Django over non-rel was basically twofold:
The non-rel project appears abandoned.
The non-rel product is "crippled" in functionality according to some of the docs I read about it and you will not be able to use all of the pre-baked goodies of Django.
I have been working on this project for 7 months now and I find Django on GAE with Google Cloud SQL very stable and productive environments. FWIW, I use PyCharm which has a one click deployment feature which makes deploying my product an absolute breeze. I've been working on IT projects with various technologies for quite some time and the combination of PyCharm, Python, Django, GAE and Google Cloud SQL would be at the top of my list of productive environments.
Of course there are other Python frameworks to consider, like Flask which allow more of a best-of-breed approach but I have no experience with them.
Hope this helps.
I'm using django-nonrel 1.4, though I haven't updated to the latest build yet. It's running smoothly for me.
You do need to recognize that if you use django-nonrel, you have to live by the rules of the GAE HRD, especially the eventually consistent results, and the limited query capabilities.
Django-nonrel is definitely not abandoned! I am using the 1.6 version with much success at Docket Alarm and it is still being actively maintained.
Here are the up-to-date links to the project:
Docs
GitHub
Discussion group

porting django app to GoogleAppEngine to deploy on appspot.com

I wanted to port my django app to run on GoogleAppEngine and deploy this on appspot.com.In my django app I am using postgres as db to store user info,sothat user login /registration is possible.
I came across this article about porting django to appengine.
It mentions that you need to use Google Cloud SQL backend .This article says that it comes with a price from june12th onwards.
So,it seems that, to I have to pay to deploy even a non commercial application? Or is there some way I can do this without using cloud sql?
I did it with django-nonrel, it requires a few modifications but it worked. Here is a guide on how to set up. After it worked for me, I realized Heroku was easier to set-up and maintain, so my other apps went straight to heroku.

How to migrate Django project to Google App Engine

I am looking for a guide to migrate Django project to Google App Engine and use Google's datastore. The most of the guides I found were linked to Django-Appengine using Django-nonrel (but I want to use GAE's native support).
Going through GAE getting started guide, it says:
Google App Engine supports any framework written in pure Python that speaks CGI (and any WSGI-compliant framework using a CGI adaptor), including Django, CherryPy, Pylons, web.py, and web2py. You can bundle a framework of your choosing with your application code by copying its code into your application directory.
I understand that I won't be able to use some features of Django in that case (majorly the admin feature) and would also need to restructure the models.
From other reading, I also found that latest SDK of GAE now includes Django 1.3 on Python 2.5.
I tried to put all files from my Django application to a GAE project, but couldn't get it all to work together.
Please provide some basic guide using which I may migrate my Django project to Google App Engine's code.
Thanks.
For an existing Django app, using django-nonrel is the simplest approach; it is very popular so you should be able to find help with specific errors you get quickly.
Another approach is written up in this article: http://code.google.com/appengine/articles/pure_django.html -- it goes the other way, taking an App Engine app that uses Django for dispatch, templates, and forms, but not for models, and describes how to make it run in a native Django environment. Maybe you can glean some useful hints for your situation from it.
I've used django-nonrel, which behaves pretty much like django, except that operations with JOINs will return errors. I've basically worked around this by avoiding ManyToMany fields, and essentially building that functionality manually with an intermediate table.
So far I've ran into two problems with Django-nonrel:
1. No access to ancestor queries, which can be run in a transaction. There's a pending pull request for this feature though.
2. You can't specify fields that are not indexed. This could significantly increase your write costs. I have an idea to fix this, but I haven't done so yet.
(Edit: You CAN specify fields that are not indexed, and I've verified this works well).
2 (new). Google is pushing a new database backend called ndb that does automatic caching and batching, which will not be available with django-nonrel.
If you decide not to use django-nonrel, the main differences are that Django models do not run under App Engine. You'll have to rewrite your models to inherit from App Engine's db.Model. Your forms that use Django's ModelForm will need to inherit from google.appengine.ext.db.djangoforms instead. Once you're on App Engine, you'd have to port back Django if you ever take your app somewher else.
If you already have a Django application you might want to check this out. You won't work with App Engine's datastore but Google Cloud SQL might fit your needs.

Django on Google App Engine

How much of a pain is it to run a Django App on App Engine? Also, does the Datastore work as-is with Django?
I spent some time trying to answer the same question... it seems to me that the most difficult thing to transfer to GAE are django's models... in the sense that they require various modifications and rethinking, mainly because GAE's backend is not a standard relational DB, but google's BigTable. I found a nice intro to this here:
http://www.youtube.com/watch?v=rRCx9e38yr8
Anyways, it's worth downloading one of those 'patches' and have a go with it!
For me the best solution is the 'app-engine-patch'. I downloaded the sample project and it worked straightaway! (Mind that you need to have GAE's SDK installed separately) A killer-feature for me is the fact that the django-admin and many other classic django functionalities have been ported too!!!
http://code.google.com/p/app-engine-patch/
The documentation is still quite minimal in my opinion, but it's good enough to get you going. It'll help you to skim though the official GAE docs though!
Just Yesterday (depending on your time zone), Google released a new SDK for Python on Appengine that supports django 1.0 out of the box.
You need to use django-nonrel (source).
You will still find loads of issues:
Many2Many relations not supported
Fake joins increase number of queries
App Engine doesn't allow any python lib with socket or C dependencies (sentry, lxml...)
You can try to get early access to CloudSQL.
Otherwise you are not constraint to use App Engine, you can think about using:
Heroku
Gondor
Cheaper and more control with support requirement files like pip.
31.01.2012, Google released App Engine 1.6.2 that supports Django out-of-the box.
App Engine includes version 0.96 of Django out-of-the-box, but it is quite crippled.
App Engine Helper and app-engine-patch supposedly fix this problem to some degree, but I haven't tried either myself.
http://code.google.com/appengine/articles/appengine_helper_for_django.html
http://code.google.com/appengine/articles/app-engine-patch.html
The amount of pain depends on how much existing code you want to reuse. Unfortunately because of the Datastore does not support SQL, you often cannot just take any django-pluggable app and use it on your GAE project.
App-engine-patch http://code.google.com/p/app-engine-patch/ looks to be ahead of the other django helpers in bringing the standard applications (Sites, ContentTypes, Flatpages) over to GAE. I have used app-engine-patch on several gae projects, and once you understand how to port a django-sql model to a django-gae model and converting sql to datastore queries things can be done very quickly - but there is always a learning curve.
appengine-helper tries to bridge the Datastore gap by providing a model so you don't have to change your model superclasses, but I've found that you end up having to change ManyToMany relationships and any sql anyway, so the advantage ends up being minimal. ae-patch has a roadmap to try to provide an ae-datastore backend, but it probably won't happen for a while.
Google has now launched their Cloud SQL storage. That is actually MySQL 5.5 in the cloud. IMO that's a very nice way to migrate your Django app into the cloud. They have a free trial up to June 1, 2013.
If you need some tips how to set up your Django project for Appengine and Cloud SQL I've written a tutorial for that.