Notes from Google AppEngine User Meetup at Barcamp Karlsruhe

Notes from Session Google AppEngine User Meetup 

at Barcamp Karlsruhe

on 19.06.2011

Attendants:

• Sebastian Helzle | @sebobo, pyhton and java
• Tobias Günther von Elaspix , java
• Tobias Müller, 1&1 @tobiasmueller, mostly python
• Max Völkel, Calpano (host) @xamde | Calpano.com, java

Topics & Tips:

Use the cookbook: http://appengine-cookbook.appspot.com/ 

Exception handling can be tuned nicely 

• to deliver errors over XMPP to GTalk
• to include relevant details such as userId involved in error

Nice frameworks:

• Objectify (mature, small, fast)
• Xydra.org - less mature, more features (versioning, access rights, synchronisation, ...)

Common issues:

• Privacy regulation in Germany make it hard/impossible to use GAE for German customers (depending on the kind of data to be stored)
• Deadline exceeded error - Solutions:
• TaskQueue, now easier to use with Deferred Task, also in Java
• Caching (static variables, mem cache, datastore)
• Asynch & batch operations (more concurrency, less datastore hits)
• Report generation - commons solutions for this special case:
• use bulk loader to download datastore, compute locally
• use task queue to generate report cleverly in pieces, deliver in 30 seconds
• use Backends (a new GAE feature) for this

Nice tools:

• JRebel for debugging
• A local embedded Jetty for debugging
• AppStats!

Hint: Go to Google developer days and talk to real people (some come form the US GAE team, some come from partner companies)

--
max@xam.de | http://Xam.de