Google released an update to its platform-as-a-service (PaaS) platform, Google App Engine, by releasing SDK version 1.3.6. The latest SDK provides two key features, multi-tenancy support and High Performance Image Serving apart from several other requested features and bug-fixes.
The latest SDK announcement is summarized in a blog post. The support for multi-tenancy is huge. Until now, your application on Google App Engine had to take care of segregating data for different customers. You had to build your own solution to store and serve data to respective accounts, in case a single application was used to serve different customers. With multi-Tenancy, this is now provided to you. What is interesting to note is that they have built multi-tenancy at the datastore, cache and task queue level. This is smart design, since multi-Tenancy is built into each of the App Engine core APIs. This gives the developer great flexibility in the way they want to implement multi-tenancy.
If your application deals with images, this release gives you direct access to Google’s infrastructure for high-performance image serving. In fact, they are making available to developers the same infrastructure that they use to power Picasa. You need to store your images using the BlobStore API (this requires a billable account) and then request a high-performance image URL that you can embed into your page. And best of all, serving from this URL, does not incur any CPU or dynamic serving load on your application.
A general limitation that most developers complain about when moving their applications to Google App Engine has been the strict implementation of request/query time outs and datastore quotas for count. This release lifts the limitation of the 1000 entity limit on count and offset. The request timeout still remains. Things are getting easier and it will come as no surprise if Google continues to relax some restrictions, based on feedback, in subsequent releases. Check App Engine's docs for full information about current quotas.
Google App Engine is a great platform for PaaS with one of most generous of quotas, available to developers today. Multi-tenancy support is a critical aspect of any hosted solution design and it has been addressed now. It will be interesting to see how other PaaS vendors respond to this.