Google Cloud Storage: concurrency controls and deeper App Engine integration

January 17, 2012


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By Navneet Joneja, Product Manager

Google Cloud Storage is a robust, high-performance service that enables developers and businesses to use Google’s infrastructure to store and serve their data. Today, we’re announcing a new feature that gives you greater control over concurrent writes to the same object, and the availability of an App Engine Files API that makes it easier to read and write data from Java App Engine applications.

Write concurrency control

A number of our customers have asked us for greater control over concurrent writes, in order to implement features like strongly consistent write operations and distributed locking semantics in the cloud. In response to your feedback, we’re announcing the release of version-based concurrency control. Every time you update an object, it gets assigned a 32-bit, monotonically increasing sequence number. This version number is returned as a header with every GET or HEAD request. You can then use a conditional write operation to manage concurrent updates to the object (for example, when you want read-modify-write semantics). This feature is currently experimental.

AppEngine Files API for Java applications

Last fall, we announced the ability to read and write your Google Cloud Storage data using the App Engine Files API for Python applications. Today, we’re making the Files API available to Java App Engine applications too. This feature is currently experimental, and we’ll continue to enhance it in the months to come.

As always, we welcome your feedback in our discussion group. If you haven’t tried Google Cloud Storage yet, you can sign up and get started here.


Navneet Joneja loves being at the forefront of the next generation of simple and reliable software infrastructure, the foundation on which next-generation technology is being built. When not working, he can usually be found dreaming up new ways to entertain his intensely curious almost-two-year-old.

Posted by Scott Knaster, Editor