We’ve now hit the six-month mark on Google App Engine. And it’s still in beta. Few of the significant shortcomings in making GAE production-ready for “real applications” have been addressed.

In an internal Gartner discussion this past summer, I wrote:

The restrictions of the GAE sandbox are such that people writing complex, commercial Web 2.0 applications are quickly going to run into things they need and can’t have. Google Apps is required to use your own domain. The ability to do network callouts is minimal, which means that integrating with anything that’s not on GAE is limited to potentially impossible (and their URL fetcher can’t even do basic HTTP authentication). Everything has to be spawned via an HTTP request and all such requests must be short-lived, so you cannot run any persistent or cron-started background processes; this is a real killer since you cannot do any background maintenance. Datastore write performance is slow; so are large queries. The intent is that nothing you do is computationally expensive, and this is strictly enforced. You can’t do anything that accesses the filesystem. There’s a low limit to the total number of files allowed, and the largest possible file size is a mere 1 MB (and these limits are independent of the storage limit; you will be able to buy more storage but it looks like you won’t be allowed to buy yourself out of limitations like these). And so on.

Presumably over time Google will lift at least some of these restrictions, but in the near term, it seems unlikely to me that Web 2.0 startups will make commitments to the platform. This is doubly true because Google is entirely in control of what the restrictions will be in the future, too. I would not want to be the CTO in the unpleasant position of having my business depend on the Web 2.0 app my company’s written to the GAE framework, discovering that Google had just changed its mind and decided to enforce tighter restrictions that now prevented my app from working / scaling.

GAE, at least in the near term, suits apps that are highly self-contained, and very modest in scope. This will suit some Web 2.0 start-ups, but not many, in my opinion. GAE has gone for simplicity rather than power, at present, which is great if you are building things in your free time but not so great if you are hoping to be the next MySpace, or even 37Signals (Basecamp).

Add to that the issues about the future of Python. Python 3.0 — the theoretical future of Python — is very different from the 2.x branch. 3.0 support may take a while. So might support for the transition version, 2.6. The controversy over 3.0 has bifurcated the Python community at a time when GAE is actually helping to drive Python adoption, and it leaves developers wondering whether they ought to be thinking about GAE on 2.5 or GAE on 3.0 — or if they can make any kind of commitment to GAE at all with so much uncertainty.

These issues and more have been extensively explored by the blogosphere. The High Scalability blog’s aggregation of the most interesting posts is worth a look from anyone interested in the technical issues that people have found.

Google has been more forthcoming about the quotas and how to deal with them. I’ve made the assumption that quota limitations will eventually be replaced by paid units. The more serious limitations are the ones that are not clearly documented, and have more recently come to light, like the offset limit and the fact that the 1 MB limit doesn’t just apply to files, it also applies to data structures.

As this beta progresses, it becomes less and less clear what Google intends to limit as an inherent part of the business goals (and perhaps technical limitations) of the platform, and what they’re simply constraining in order to prevent their currently-free infrastructure from being voraciously gobbled up.

At present, Google App Engine remains a toy. A cool toy, but not something you can run your business on. Amazon, on the other hand, proved from the very beginning that EC2 was not a toy. Google needs to start doing the same, because you can bet that when Microsoft releases their cloud, they will pay attention to making it business-ready from the start.