When splitting traffic to different versions of your app, which version is the default version

Question

This question is related to an issue when running a Python 2 and Python 3 version of an application with split traffic that uses the Task Queue.

Looking at the taskqueue.py module, I've gathered that the target for the Task is set to the DEFAULT_APP_VERSION, however I do not know how this is determined when two versions of the app are considered the default version.

Answer 1

As of the moment, there is no option to determine or select the default version of a service when traffic is split. The only thing I could observe is when traffic is 100% allocated on one version, that would be considered as a default version, since I am unable to delete it.

Before there was an option to just select the default version when you create multiples of it but it was no longer available. Link for the document here.

When I migrate all traffic to another version, it would change to [project-id].[region].r.appspot.com. I would consider this to be the default version as no other versions are being used and no traffic is being split.

You can check out the definition of target wherein:

Push tasks only; specifies the alternate version or backend on which to run this task, or DEFAULT_APP_VERSION to run on the application's default version. You can specify a module or version, a frontend version, or a backend on which to run this task. The string that you specify will be prepended to the domain name of your app. If you specify the target argument, do not specify a Host header in the dictionary for the headers argument.

Link for the taskqueue documentation through this link.

If selecting the default version is badly needed for your project, I would suggest filing for feature request. This is not a guarantee that it would be available in the future but it's worth a shot.