I am looking for a simple python web framework which runs both as standalone and on Appengine.
I would like to write the app in such a way that i can switch between standalone and Appengine based on the deployment configuration. Standalone will be using RDBMS.
When i checked web.py looked simple and promising. I have the following questions:
Does web.py work well on Appengine?
Is there any major known gotchas?
Can you share your experience with using web.py on Appengine?
Any suggestions to achieve the above mentioned goal is appreciated.
Does web.py work well on Appengine?
Yes it does work pretty well, it's compact and very easy to use.
Is there any major known gotchas?
Web.py does not offer any Data Abstraction Layer compatible with GAE; that means that in order to switch from a RDBMS to a NoSQL database, you have to create by yourself a layer above both the web.db database API and the Google App Engine datastore API.
Can you share your experience with using web.py on Appengine?
I have deployed a couple of simple applications with web.py on top of GAE and other several pet projects with Sqlite as database; here a mini review.
Any suggestions to achieve the above mentioned goal is appreciated.
If the switch from Appengine to RDBMS is your primary concern, have a look to web2py.
Although with some limitations, to the best of my knowledge is the only one Python web framework GAE friendly that offers a DAL above the App Engine Datastore and other several RDBMS solutions.
Switching from one db to another is just a matter of initializing the DAL with the proper connection string:
db = DAL('sqlite://storage.db')
db = DAL('mysql://username:password#localhost/test')
db = DAL('gae')
No webapp framework on its own is going to be able to do this - the App Engine environment consists of a lot more than just a database interface and a CGI environment. Even if it could, any DAL that supports both the datastore and a relational DB is likely to sacrifice most of the flexibility of both in pursuit of that.
Your best option, if you want to take advantage of more than just the datastore, is to write your app for App Engine, and use AppScale or TyphoonAE to run your app outside the App Engine environment.
Consider using webapp2. It is similar to web.py, provides basically the same featureset, and runs outside of App Engine out-of-the-box. Besides, you get stellar compatibility with App Engine SDK and libraries (I explain it better here).
You'd only need to add a relational database library. But this is an easy choice: SQLAlqchemy is pretty much the standard in Python land, with lots of documentation and a thriving community.
I would also suggest web2py. Great framework, great community, plays out-of-the-box outside of AppEngine. It also supports a lot of databases (SQLite, PostgreSQL, MySQL, MSSQL, FireBird, Oracle, IBM DB2, Informix, Ingres, and Google App Engine).
On top of that, it's trivial to install it on Linux, Windows, Mac.
Related
I am to develop an app, and I have to choose between Ruby on Rails or Python+Django. So far I want to do it with Ruby on Rails, because i feel more comfortable doing what I have to do on it.
But there is a problem. There would be a client app written on Python that has to communicate with mine. Cause that app should be able to communicate with mine.
First: I think if it is a matter of communicating with the MySQL database there wouldn't be an issue, cause the Python app is able to query to MySQL server with proper authentication right?
Second: and more important question: If I have a Ruby written API, to ease the queries, Could the Python app be able to invoke functions in that API and get the results? If it is possible, How could I achieve that?
Ruby on Rails 5 supports API only app, if you are using this app for APIs only, else just create a normal app and expose API endpoints that render json outputs. Use Active Record for mapping your MySql database and jbuilder for json views (both of which are available by default when you create new app). You will find lots of tutorials if you google Use Ruby on Rails as API app.
Good luck with it.. :)
I may be late to the party, but I've been playing around with Google App Engine.
My plan was to convert an existing open-source Django app to run on GAE.
I went through the O'reilly book, Programming Google App Engine to get the gist of GAE.
I'm ready to start diving in, but I'm curious as to the best way to approach it.
I Django-nonrel currently the best option to use?
My Google-fu isn't really turning up many examples of people converting a Django app to run on GAE. The few that I have found seem to date to 2010 or earlier. Is this because people are not finding it worthwhile to use GAE with Django?
What has been your experience porting Django apps to GAE?
Google App Engine now supports SQL databases so you can have a regular django app on GAE. Here is the official documentation, and here is a nice tutorial from another related question.
I have personally run django sql (and nonrel) apps on gae and they have been fine.
Webpy.org - Who uses web.py?
"[web.py inspired the] web framework
we use at FriendFeed [and] the webapp
framework that ships with App
Engine..."
— Brett Taylor,
co-founder of FriendFeed and original
tech lead on Google App Engine
Google App Engine Getting Started for Python
HTML embedded in code is messy and
difficult to maintain. It's better to
use a templating system... ...For your
convenience, the webapp module
includes Django's templating engine
Questions:
What are the differences between webapp and webpy?
Is it worth the trouble to bundle webpy when Appengine already offers webapp?
What I know:
1. Web.py has a templating language of it's own(it looks easier than Django's)
2. Currently, the only reason for which I am thinking about using web.py is to avoid using(and learning) Django for templating on appengine.
3. The quotes at the head of this question
4. I have been through related questions and through the webapp documentation on Google.
5. I have noticed that stackprinter uses web.py and is hosted on appengine.
web.py experience:
I started to use web.py three years ago when I decided to learn some Python web frameworks.
The first thing I loved of web.py was its simplicity; I was searching for an essential microframework without all the batteries that you can find in other bigger projects like Django or Web2py for example.
So I developed a couple of projects (deployed with fastcgi) and learned all of the web.py library features, Templetor included.
Then I discovered Google App Engine and started to use Webapp; it was a boring process because instead of using python (like Templetor or Mako), it forces you to learn a new templating syntax that it is very restrictive by default.
While Developing StackPrinter I found that Google App Engine was supported by web.py so I removed Sqlite, made some minor tweaks and started to use GAE datastore.
Web.py was my first love in term of Python web frameworks and it's fair to say that I'm a little biased to talk about it.
I'm sticking with web.py for my pet-project on GAE because I'm fluent with it and templetor is lightning fast.
I like the fact that I can use Python for templating and the easy way to share some data or functions globally to the views, I like also the rich toolset of utilities for encoding, markdown and so on.
Webapp vs web.py:
I think it's not fair to compare them because Webapp is a simple framework that just provides the minimum easy tools to get started; many features are missing like I18n, validation, processors or even the basic cookies handling.
Check Webapp-improved for something better.
My recommendation:
If your focus is mainly on developing for Google App Engine, I would recommend you to go with some framework made specifically for GAE like Tipfy.
If you are searching for a pythonic web framework to play with on your side-projects, web.py is a good project to study and to follow.
Differences between webapp and web.py
The primary differences (IMHO) are that:
The webapp framework was designed specifically for Google App Engine (GAE). The web.py framework was not designed specifically for GAE.
"The webapp Framework is the default tool set for building web applications [in Google App Engine] but not the only one." (Source: Developing with Google App Engine by Eugene Ciurana)
They use different templating languages—web.py uses its own, whereas webapp's templating language is based on Django.
Other Python frameworks for GAE
Other Python frameworks for GAE—neither of which use the Django templating language—include:
Flask — "A microframework for Python based on Werkzeug, Jinja 2 and good intentions."
tipfy — "A small but powerful framework made specifically for Google App Engine. It is a lot like webapp, but offers a bunch of features and goodies that webapp misses: i18n, sessions, own authentication, flash messages and more. Everything in a modular, lightweight way, tuned for App Engine."
Is it worth the trouble to bundle webpy when Appengine already offers webapp?
Personally, I think that it is worthwhile to use something besides webapp. However, I would lean toward Flask or tipfy.
Alex Martelli endorses tipfy in his answer to the SO question Google App Engine - Secure Cookies. The main takeaway for me from Alex's answer is that tipfy is:
Designed to work with GAE
Lightweight
Contains built-in functionality that you often want
They're very similar, it just happens that webapp is more tailored to GAE than web.py. webapp is very small and is definitely optimized for writing for App Engine, so if that's your cup of tea, you should use it. You did say you didn't want to use Django's template system (I don't know why, it's pretty easy), which is what webapp comes with by default. The template system can be changed, but I recommend you give the Django engine a try.
That said, if you don't like it it's not terribly hard to set up with a new framework (basically anything WSGI compliant ought to work). If you want to use web.py, by all means, set it up, but you may have to do a little searching on how to set it up and configure everything to work.
Basically I have a webfaction space (assume for the purposes of this question that its free).
I am trying to learn python by created some simple web applications on Google App Engine using Eclipse + Pydev for development.
So far I have some basic functionality working in App Engine, though I have had some frustration with some library imports not working and whatnot (this may not be app engine specific).
So, is it worth it to switch now to webfaction, and leave GAE?
I am trying to learn python by created
some simple web applications on Google
App Engine using Eclipse + Pydev for
development.
This seems reasonable. Nothing wrong with using GAE, Eclipse, and Pydev to learn to do Python web dev.
So far I have some basic functionality
working in App Engine, though I have
had some frustration with some library
imports not working and whatnot (this
may not be app engine specific).
So, is it worth it to switch now to
webfaction, and leave GAE?
You haven't provided much of a reason to leave GAE now that you've started there. I think that "some frustration" is normal for learning on any platform.
Beyond that I think this could descend into a general GAE good for learning vs. GAE bad for learning discussion.
So let me get that started...
Since GAE is a 'Platform as a service' (PaaS) it makes deployment and maintenance very simple. You can get right to coding and not worry about the platform. As well, this platform provides some services, such as e-mail and authentication that make those tasks very easy. For example, on first pass you can just make use of their authentication API (supports Google and now openID authentication I think) and leave more complicated authentication options for later.
On the other hand, this platform is kinda' non-standard. The datastore is the main issue and that affects Django. That's a pain because it means that the Django running on GAE is slightly different then the standard Django and the Django docs that you are reading might not apply for GAE, etc.
Here is a current thread about getting started with Django on GAE (which addresses the datastore issue):
http://groups.google.com/group/google-appengine-python/browse_thread/thread/8d1c945d27b6305f
Hope that helps.
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Are there any guidelines to writing Google App Engine Python code that would work without Google's infrastructure on other platforms?
Is there any known attempt to create an open source framework which can run applications designed for Google App Engine on other platforms?
Edit:
To clarify, the question really is:
If I develop an application on Google App Engine now, will I be able to migrate to another platform later, or is it a lock in?
There's a number of components required to make an app fully portable:
The runtime environment itself. This can be ported relatively simply, by setting up a CGI or FastCGI server that emulates the App Engine environment (which itself is basically slightly-enhanced CGI). Most of the code to do this is already in the SDK. Unfortunately, there's no easy pre-packaged toolkit for this yet.
The datastore. By far the most complicated API to port. There are a number of efforts underway: AppScale runs on EC2/Eucalyptus/Xen and uses a HyperTable or HBase backend; it's still very much beta quality and they don't distribute the data connector separately (it's the beginnings of a complete run-your-app-on-your-own-cloud solution). Jens is/was writing an SQLite backend, and there's my own project, BDBDatastore, which uses BDB-JE as the backend, and is fully functional (though beta quality). AppDrop, which others have mentioned, simply uses the development server as a backend, and hence isn't suitable for production use.
The users API needs replacing with something else, such as an OpenID based API. Again, fairly simple, but no premade solutions yet.
The Memcache API needs a backend that uses standard C memcache backends.
The other APIs have perfectly functional backends as part of the SDK, so don't really need porting.
Cron support would also need implementing, as would background processing, XMPP, etc, when they become available.
As you can see, there's a lot of work to be done, but no fundamental barriers to making your App Engine app run outside Google's environment. In fact, if you're interested, you're more than welcome to participate - I and others have plans to combine the solutions for the various pieces into a single 'OpenEngine' solution for hosting your own apps.
Use a high level framework that works on App-Engine. That way you can port your code to other servers when you want.
django has been patched and ported to work in the Appengine patch project and is the most used FW on appengine.
You may want to refer this step by step intro to running a django app on App engine
As far as the parallel infrastructure to run an app engine application is concerned, it is still way far. App Engine itself hasn't got as popular as people believed it to and google wanted it to be. Plus it is harder to develop on the builtin WebApp framework than on django.
Its quite unlikely to see a parallel infrastructure to run app engine application on, atleast for years to come. Rather it is likely to see django and other popular frameworks work out of the box on app engine and the work on this is currently underway in the referred project.
You can build AppEngine applications using the Django python framework (although the supported version is a bit behind the most recent Django release). Where you lose portability (at least right now) is when using GQL/BigTable for persistence. This is Google proprietary database platform. As Hank mentioned this is one of the biggest reasons to actually use AppEngine, but it is also the single largest locking point.
Here are a couple of links to Django support in AppEngine and GQL/BigTable:
http://code.google.com/appengine/articles/django.html
http://code.google.com/appengine/docs/python/datastore/gqlreference.html
So far, I found an experimental host called app-drop which is capable of hosting google app-engine projects. This should mean that it's atleast possible to run app engine projects outside of google's infrastructure.
This is however clearly not yet suitable for production.
The code should be mostly portable (they do a pretty good job of indicating which modules you can't use on AppEngine and which AppEngine-specific code corresponds to which forbidden modules), but the whole point of AppEngine is to get access to Google's infrastructure. There's not much point to writing your code to the AppEngine restrictions if you aren't going to be using their infrastructure.
AppDrop is a proof of concept port of AppEngine to Amazon Web Services / Elastic Computing completed in April of 2008. It uses a flat file instead of BigTable and runs in a single instance, so there are scaling issues; but it's developer says it took him only four days, and perhaps these limitations can be addressed by others.
I did the reverse migration from vanilla Unix to app engine recently very easily by using WHIFF resources. Basically configure anything platform dependant as a resource and then swap/replace the resources on different configurations.
http://piopio.appspot.com/W1000_1000.resources
also see
http://aaron.oirt.rutgers.edu/myapp/docs/W1100_1200.wwiki
for a detailed example of resource swapping/configuration.
(note: links may go away eventually, app is experimental.)
Check out typhoonae. it's in beta, but quite usable – we moved one of our apps to inhouse server running this stack.
AppScale is the most mature open source implementation of Google App Engine. It's been in development since 2008 and currently support all four languages: Python, Java, Go, and PHP. It has users running their application in production today.
The FAQ explains what APIs are supported and what is lacking:
https://github.com/AppScale/appscale/wiki/FAQs
(Disclaimer: I work on the project)