cloud.google vs google.golang?

[R S]

For google app engine Go apps,

Should I be using the libraries from cloud.google.com/go or google.golang.org/appengine ?

They seem totally different?

[Jordan (Cloud Platform Support)]

It depends which App Engine environment you choose (Flexible or Standard). The App Engine Standard environment uses the older App Engine specific APIs, where as the Flexible environment uses the newer Google Cloud Client Libraries for Go (which is being developed by the engineering team in their Git repository).