Google Cloud Platform Blog: Python 2.5, thanks for the good times

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Python 2.5, thanks for the good times

Friday, March 8, 2013

Python 2.5 has a special place in the heart of any Google App Engine developer, as it was the first runtime we launched way back in 2008. Since then, both Python and App Engine have advanced a great deal.

A year ago we announced our support for Python 2.7, which brings syntactic and semantic improvements to the language and includes powerful features like threading and a large selection of third-party libraries.

Not only does Python 2.7 make developers’ lives easier, the runtime is extremely cost-effective. Our customers have taken advantage of features like concurrent requests to reduce their front-end instance costs by more than 70% while handling the same amount of traffic.

Not surprisingly, the Python 2.7 runtime has proven to be extremely popular. Just over a year after launch, more than 78% of active Python applications on App Engine are using the new runtime, and more are being added every minute.

As both Python and App Engine evolve, we must occasionally make hard choices about which legacy runtimes we should continue to support. Today we are announcing the deprecation of the Python 2.5 runtime. The deprecation period will follow the guidelines set in our terms of service.

What does this mean?

We will continue to run Python 2.5 applications throughout the deprecation period. For most customers, upgrading to Python 2.7 is trivial as most elements of Python 2.5 are forwards-compatible with Python 2.7. We’ve prepared a handy migration guide that covers the steps to migrate in detail.

If your application is still using the already deprecated Master/Slave Datastore, then you should first plan the migration to our more reliable High Replication Datastore, as the Master/Slave Datastore is not accessible from Python 2.7.

Future versions of the App Engine Python Development SDK will display warnings to developers deploying updates to a deprecated runtime.

Starting from January 2014, we will no longer allow new applications to be created using the Python 2.5 runtime.

We encourage all developers using Python 2.5 to consider migrating as soon as possible. We’re confident that the vast majority of our customers will find the upgrade straightforward and the benefits substantial.

If you’re considering migrating, here are some useful resources:

Our summary of the new features we’ve introduced in Python 2.7 including additional standard libraries and third-party libraries that are supported.
A handy migration guide, explaining the steps to move a Python 2.5 app to Python 2.7
App Engine engineers give an in-depth discussion during Google I/O on the many improvements in Python 2.7, and how to quickly take advantage of them.

If you have any questions about this deprecation, we encourage you to contact us at google-appengine-python25-deprecation@googlegroups.com.

-Posted by Andrew Jessup, Product Manager