When we release the project with maven (mvn release:prepare and mvn release:perform), this version number gets automatically increased to the next development version, for example from 0.0.1-SNAPSHOT to 0.0.2-SNAPSHOT.
The main problem is that google app engine uses another version descriptor in the appengine-web.xml file that is independent from the first one:
It would be great to get those to versions number synchronized! Here is a solution how to get it working:
Define a tiny groovy script, let’s say utils.groovy, that will define a property defining the gae version. The problem is that we can’t use the maven version directly since gae does not accept ‘.’ and ‘-SNAPSHOT’ in it’s version. So this script will map the gae version to the maven version in that way: X.Y.Z(-SNAPSHOT) -> X-Y-Z . Of course we will lose the SNAPSHOT information, but this is not really relevant in gae terms. Your application will be deployed at X-Y-Z.latest.myproject-site.appspot.com.