Can someone from GCP explain why the App Engine standard environment has such long lead-times in terms of language support? What is required, infrastructurally, to ship a new standard-environment language?
Historically supporting a language on App Engine required modifying the languages libraries to work on proprietary parts of Google infrastructure. This entailed a decent bit of effort on our part, and also meant that some apps & code wouldn't execute correctly.
We now use technology based on gVisor (https://github.com/google/gvisor) in production for App Engine standard. This allows us to release new language runtimes unmodified. Node.js support is the first runtime based on this new stack.
We completely agree that we should be releasing support for new languages & major versions more frequently...
(PM on the team) To be able to deliver Node.js on App Engine Standard, we had to develop an entirely new sandbox environment. You can learn more about it by watching this I/O talk (starting at 15min): https://youtu.be/ogexnfng_hE?t=14m48s
