i'm developing a web site hosted on AppEngine and wanted to use Django for some tasks. I've read these two answers:
Django on Google App Engine
Django and App Engine
But those are pretty old, and my question is a little more specific. I've taken a look at django-nonrel and seems good, but i've not used it and cant affirm anything.
So, the question is. Can I use the Admin site and the forms from Django with this package? If not, do you know any other patch that allow me to use them?
Thank you very much!
If you use django-nonrel, then you can use the Django admin site but it will be limited to the types of queries you can do on app engine. I personally found it easier to code my own simple admin interfaces that to type to make things work in Django Admin.
Regarding forms, regular Django Forms and ModelForms work quite well.
Yes, you can (both Admin and forms).
(definitely) :)
I installed djangoappengine 3 months ago and work on it daily under Eclipse (Windows).
If you have some expericence with Django it should be easy, I faced much more problems with Eclipse integration, but nothing unfeseable (even for a newbie - as I'm still).
You just have to start from here:
http://www.allbuttonspressed.com/projects/djangoappengine#installation
Be careful anyway: there are some limitations due to the Datastore capabilities.
A lot of work has been done to circumvent them (dbindexer, specifics decorators...) and if you're planning to develop an app from scratch you will find your way (keeping " noSQL " in mind) but if you plan to migrate a plain vanilla SQL app, it may cause you some pain...
Last point: instances handling Django and all its libraries may be long to start with App Engine ; an issue to consider:
http://code.google.com/p/googleappengine/issues/detail?id=1695
Hope it helps.
Florent
Related
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.
According to this question:
Django on Google App Engine
The easiest way to get started with GAE/Django is with the Django non-rel bundle. However now that the latest Python/GAE SDK includes a build of Django, do we still need this?
What's the best-practice for getting started wth Django on GAE right now?
Thanks
Update: It seems that Web app2 is the easiest choice for new projects.
This guest article suggests that
"App Engine does come with some Django support, but this is mainly
only the templating and views."
non-rel is still seemingly your best bet. Although I'd caution you that further development and/or maintenance may not happen according to their blog.
Normal Django's models doesn't have a backend supporting GAE's datastore. Hence you can't use Django models, and hence, Django's model forms. What you'd have to do use use models derived from GAE's python db.Model(). Instead of using Django's ModelForm class for forms, you would use google.appengine.ext.db.djangoforms. Note, that's specifically for ModelForms, other forms work fine since they're not tied to the database.
I can think of two good reasons to use Django-nonrel:
1a) you have a existing project on Django. Using Django-nonrel would be the laziest way to go. Rewriting models to GAE's models isn't too hard, but it could be a small pain, especially if
1b) you use a lot of existing Django components, and you'd have to go through all of them to update the models and forms.
2) You want to hedge your bets against GAE. Using Django-nonrel will allow you to switch over to MongoDB with very little effort, since Django-nonrel has a functioning MongoDB backend. The current Django-nonrel maintainers seem to be more interested in MongoDB.
Having worked with Django-nonrel, I've so far run into some reasons why it may be a bad choice:
1) No support for ancestor queries. There's an outstanding pull request for this though. It won't be compatible with any other DB backend though.
2) ndb is coming out, and seems like it'll have a few more benefits, that likely won't see support on Django-nonrel.
If you do use GAE's native db API, the main benefit from Django would be the form validation. Otherwise, webapp2+jinja2+gae db.Models() would provide similar functionality to Django.
I am looking for a blog solution to run inside a Django project deployed on the Google App Engine. After a bit of review I decided to try out Mezzanine v0.11.3. I've overcome the hurdle of getting it in project using the advice of others deploying on App Engine at this link: http://groups.google.com/group/mezzanine-users/browse_thread/thread/c8b13c41a3168c94.
Mezzanine is now showing up in the Admin, but clicking on Blog posts leads to a multi-table inheritance failure. I believe that this is due to multi-site support functionality in Mezzanine via use of the Django sites framework.
Has anyone overcome this issue? I'm going to try to use django-dbindexer but I'm not confident it will work.
*Update: as far as I can tell, the folks at AllButtonsPressed don't have any magic solutions to work around ManyToManyField issues yet, so I think that option is dead.
If no one knows a work around, do any of you know of a good blog solution I can run inside a Django project on the App Engine?
*Update: found this post Integrating Blogger into a Google App Engine App. Will investigate if this solves the problem.
*Current Status:
I have not been able to solve this problem and I don't think it is currently solvable. Thought I would share what I found through my investigations though; maybe someone out there can carry on and come up with a solution.
Options tried:
Bloog
I looked this over but it is a Python
solution, not a Django solution and I
didn't want to do the work to turn it
into one
Byteflow ( https://bitbucket.org/piranha/byteflow/wiki/Home ) notes:
designed to be standalone, will need a
lot of edits to settings.py,
inclusion of 12 additional apps and
overrides on account settings plus
hand tuning at every upgrade.
AppEngineBlog ( http://code.google.com/p/appengineblogsoftware/ ) notes:
written in appengine specific code,
not maintained, no example sites
available to see how it looks
Coltrane ( http://code.google.com/p/coltrane-blog/source/browse/ ):
simple blog constructed from standard
Django functionality no development
or support, basically need to use
this code as a way to develop your
own blog and go from there
Flother ( https://github.com/flother/flother ):
found via Coltrane comments, probably
embeddable without too much trouble,
requires 8 additional apps,the photos
and places components have
ManyToManyFields that would have to
be re-written or these components
disabled
Blogger API ( http://code.google.com/apis/blogger/ ):
use Blogger at whatever location you
wish to gain fully functional
blogging capabilities, then use
Blogger API to deliver content to any
other site you wish to display it
Flother came close to what I need but there is still a fair bit of uncertainty and effort there. I'm proceeding with the Blogger option as the only viable choice for me at this time.
Well, as far as I can see, there is no way to get Mezzanine running on GAE other than wading into the code and ripping out anything relating to a ManyToManyField (Sites support, Photos and ... something else. Can't remember what).
The only thing I could find out there that has the potential to be added to an existing project, uses only portable Django code (app engine specific) and runs on App Engine is http://www.allbuttonspressed.com/projects/allbuttonspressed . I haven't actually tried to integrate it yet because I'm going to see if the Blogger solution works.
I've been using bloog for two of my blogs without any serious troubles so far - there are few little quirks that make it mildly unpleasant sometimes but nothing that's been a deal breaker.
I use the Blogger solution and it works fine, especially if you're only one person and you run the whole site.
The problem comes when you want to others to help you out. Now every css and design decision needs to be sent to a programmer who hacks away at django templates. A CMS with a real WYSIWYG editor would allow you to ship off that work to marketing/design people and let you focus on the fun stuff.
I came across a decent review of the various blogging engines for Django, however, it's unclear how well they each integrate with GAE.
I have deployed Mezzanine/Cartridge in GAE succesfully but I have not documented it yet in github or something like that. It works using python 2.7 of course and django 1.5. Additionally it works with Google Cloud SQL, and the local file system GAE provides. It additionally works with google gmail facilities. For thumbnailing I am using local GAE functionality.
It requires several additional libraries like boto, but it works well.
See a short demo in midevocional365.appspot.com/
Do I need either to make Django easier to use on GAE? Anyone had good or bad experience of either or any equivalent? Is there much difference between these? Which is easier to use?
Regards
Geoff
I am assuming you want to run django on app engine (otherwise using appengine API directly is the best solution).
Altho' Google App engine supports django 1.0 out of the box, django admin, auth doesn't work on it, as they are dependent on the models.
Appengine patch patches django to make the admin work even on the Bigtable API.
Appengine patch also often makes sure to work on the latest release of django.
So, again, "You should use App engine patch"
Google App Engine Patch seems to have died sometime around August 2009.
http://code.google.com/p/app-engine-patch/issues/detail?id=253
I think it depends on what exactly you want to develop.
You should use app-engine-patch if you need the Django Admin interface, otherwise google-app-engine-django should be enough.
Use Django patch if you already have django application that you know that you want to use. Remember that GAE comes with its own API/applications.
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.