Hello World in Python for Google App engine.
1. First issue with missing MySQLdb library on my machine

Description

karlo@karlo-Satellite-L670:~$ uname -a
Linux karlo-Satellite-L670 2.6.38-12-generic #51-Ubuntu SMP Wed Sep 28 14:27:32 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
karlo@karlo-Satellite-L670:~/google_appengine$ ./dev_appserver.py ~/HelloWorldAppEngine/helloworld.py
WARNING  2011-11-26 15:34:39,757 rdbms_mysqldb.py:90] The rdbms API is not available because the MySQLdb library could not be loaded.
Traceback (most recent call last):
  File "./dev_appserver.py", line 77, in <module>
    run_file(__file__, globals())
  File "./dev_appserver.py", line 73, in run_file
    execfile(script_path, globals_)
  File "/home/karlo/google_appengine/google/appengine/tools/dev_appserver_main.py", line 682, in <module>
    sys.exit(main(sys.argv))
  File "/home/karlo/google_appengine/google/appengine/tools/dev_appserver_main.py", line 571, in main
    root_path, {}, default_partition=default_partition)
  File "/home/karlo/google_appengine/google/appengine/tools/dev_appserver.py", line 2983, in LoadAppConfig
    raise AppConfigNotFoundError
google.appengine.tools.dev_appserver.AppConfigNotFoundError

Solution

karlo@karlo-Satellite-L670:~$ sudo apt-get install python-mysqldb