Some time ago we started adding modules or classes to axon that were not really the core of the system. The most important one of them is a MongoDB based event store. The amount of testing of this module was not as high as the other parts. It has not yet been tested in a production system. Still it was part of the core of Axon. Next to the MongoDB based event store we also developed a Google App Engine based event store. This was not in the core of axon, in fact it was only part of a sample project in Github. A few weeks a go we decided it would be better to add an incubator to axon and put these modules or classes that have not been tested as well as the core of axon in there. THe third module is the experimentation of Allard with a distributed command bus. Feel free to check out the code and use it or comment on it through the mailing list. But be warned that this code is under development and might therefore be less stable than the other parts of axon.

This blog post focusses on the Google App Engine module that can now be found in the incubator. I'll summarize the required changes to the axon framework so it can be used on google app engine. I did blog about this topic before, so I am not going into details for all the code, but point to the older blogpost where possible and focus on the new stuff.

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