My bet is on Ruby, though I would love to see Python3 on the platform.
My bet is on node.js meaning JavaScript :)
That seems closer
AppEngine is not build to support node.js async model, my bet is on Ruby.
I'm not a web developer so I have to ask whether Ruby is that different from Python so that another tool chain gets added and maintained.
Edit: your point about node.js makes sense though.
I've never used App Engine before -- what is it about its design that precludes Async?
Knowing that the V8 team dislike javascript so much that they created Dart (and Lars Bak says this openly), it's hard for me to think about google including node.js to AppEngine
Because noone can order anyone at Google to work on anything except what he likes to?
C# / .net runtime.
Seriously, why not provide a migration path from Azure.