WordPress plugin licensing: Google App Engine vs. Amazon EC2

In the introduction to this series, I outlined some of the requirements for the WordPress plugin licensing platform: Speed, reliability and scalability. These are critical. Just imagine what would happen if any of those were missing.

Requirements Justification

A slow platform might result in significantly fewer sales. One of our use cases is to provide a free, limited time trial, and poor performance when installing or using a plugin would almost certainly decrease sales conversions. Reliability issues would, at a minimum, reduce developer confidence when coupling a new plugin to the licensing platform. Finally, if the speed and reliability don’t scale then the market of potential consumers is limited to smaller plugins.

Possible solutions

Fortunately the problem of speed, reliability and scalability have already been solved. I know that it’s possible to build out servers, load balance them and otherwise build out systems to achieve these three aims, but I have something much simpler in mind. The two most compelling options available today both allow a developer to leverage the infrastructure of very large companies that exist solely on the internet: Amazon and Google.

The business model of both Amazon and Google require them to build out their own internal infrastructure to accommodate peak volume. The big downside to this is that the majority of the time, some or most of that infrastructure is sitting idle. A somewhat interesting upside to the scale of their infrastructure is that they have had to develop internal processes that enable them to expand supply in step with demand. In other words, they have to be able to add additional resources on the fly in the event of a new record peak. That may not sound as impressive as it is 🙂

At some point, each of these companies realized that they could leverage their unused infrastructure to increase their revenue. They more or less sub-lease existing resources to third parties. As this product model developed they may have isolated the resources they sell from the resources that power their main websites, but there is still a great deal of play between them. The two offerings are Google App Engine (GAE) and Amazon Web Services (AWS).

App Engine vs. Amazon Web Services

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There are many more differences between these two platforms than I have time to get into here. However, one distinction between the two is helpful. Amazon offers a wide range of services (they add new services often) that provide the developer with a great deal of flexibility. However, the burden of choosing the right platform components and interconnecting them is also on the developer.

Google on the other hand has a more narrowly defined and inclusive platform. Rather than separating content distribution, processing, messaging, etc., Google keeps it all under the same hood. This reduces complexity for the developer at the cost of some flexibility.

This distinction is rather natural when you consider the diversity of products and engagement channels employed by Amazon and compare that to the more narrow range of services and engagement channels employed by Google.

The winner?

For the licensing project that I’m developing in this series, the scope is well defined and not overly complex. Google App Engine is the most appealing due to the ease of working in a local development environment and the ability to deploy and test on the live platform under the free quota limits (no initial cost or setup). It’s important to note that choosing Google’s platform instead of Amazon’s doesn’t make Amazon the loser and it doesn’t have to mean that I need to exclusively run on Google’s platform forever.

GAE provides both Python and Java enviornments. If I choose Java and approach the design carefully (e.g. good datastore abstraction…), it may not require too much effort to deploy on an Amazon EC2 instance if that becomes more appealing down the road.

Conclusion

The WordPress plugin licensing system will target the Google App Engine platform initially. Special attention will be given to abstracting the datastore so that I can take advantage of Google’s fast and scalable datastore and leave myself flexibility to move to an alternate if I deploy on Amazon’s platform in the future. Java is a first class citizen on both platforms. This provides some assurance that mainstream, mature frameworks will run smoothly. It also typically means that there will be plenty of documentation and support to accelerate development and deployment along.