Monday, March 5, 2012

Google App Engine & Two new Babies

My gosh! Many activities were going on the last months. First our lovely new son arrived:

Then I finally released a new website called It’s all about the financial crisis in Europe and the rest of the world (called "Krise" in German). The content is community-driven.

I developed on the Google App Engine (GAE) / Java. Starting with a little evaluation on cloud-platforms, I decided to go with GAE.
All in all it was a fun and expedient experience. Nevertheless there are pitfalls and Google’s cloud-platform still feels “green” on some edges. I will blog about some of the pitfalls later on.

I chose the following frameworks, which work well for me.

  • GAE Java Runtime
  • Spring 3.0.x (particularly Spring MVC)
  • Freemarker
  • Sitemesh
  • GAE’s Java Datastore API (wrapped with the good old Data Access Objects [DAO pattern])

Grails wasn’t an option because it doesn’t work very well on GAE.

My positive résumé on Google App Engine:

  • Setup, deployment and scaling is a no-brainer
  • The specific GAE API is proper and easy to use
  • Local development environment based on Eclipse works fine
  • Out of the box administration tools and monitoring capabilities available
  • Common services like emailing, asynchronous queuing, mem-caching, authentication etc. are available and easy to use
  • Scaling (as far as my JMeter tests predict)

My negative résumé on Google App Engine:

  • Some restrictions on the usage of Java’s SDK API (and thus some frameworks are not working well with GAE)
  • Feedback and support from Google and the community is improvable compared to others (e.g. Grails)
  • Critical bugs take sometimes too long to get recognized and fixed from Google (e.g. Website broke because wrong CSS mime-type)
  • Small down-times from 2 to 5 minutes in 24h the first days (running on HR Datastore)
  • Whenever there is a misbehavior in Google’s resource/scaling management, the customer has to pay. Nice business model: Introduce a misbehavior on customer’s platform and revenue goes up. ;) (e.g. Scheduler behavior and Slow requests). I will blog another example the next days.