GAE Managed VMs (beta) - define your own environment on top of GAE
Google is bringing new alternative to standard Google App Engine environments: Java, Python, GO, and PHP. Now you will be no more constrained to any predefined development environment / language - you can configure your own Managed VM using Docker. Managed VM will be spawn on demand to handle your application traffic in similar way as Google App Engine instances are spawn. But using Managed VM you will be able to develop application using any language and environment you want. Now Managed VMs (aka GAE 2.0) are in Beta phase - see docs: https://cloud.google.com/appengine/docs/managed-vms/