Parallel Module Deployment using App Engine SDK

TL;DR Is there a way to deploy App Engine modules in parallel?

I've built a go application using Google's App Engine SDK for Go. This application defines multiple modules. These modules are self-contained, and do not require any sort of dependency across other modules.

When I attempt to deploy the modules to the Google Cloud, I can't help but notice that the modules are uploaded sequentially. This would be fine if deployment was relatively quick, but each module requires it's own redundant compilation of the Go binary. Hence, on top of the regular upload time, I have to wait for my app to compile [module count] x [compilation time] every time I want to deploy.

The obvious (quick) solution is to deploy in parallel, so I created a simple bash script to deploy each module independently. The problem I immediately encountered with this "solution" was a HTTP 500 response from the App Engine API. The whole umbrella application, spanning across all the modules, seems to "lock" whenever any individual module is updated. This scenario creates a race condition, under which only the first module to trigger a deploy succeeds and the others fail.

I fear that this is a holdover from the legacy languages in App Engine. Since every module uses the same Go binary, it doesn't really necessitate multiple compilations of the same code. Repeated compilation is redundant, and there is no way to circumvent the lock.

One hypothetical solution, which I have only a vague understanding of, is to compile in parallel and deploy in series. I imagine that this approach would involve taking apart the configuration tool and reworking it to execute in the aforementioned manner- though I can't say for sure (yet).

Any help here would be much obliged. Thanks!

You can deploy to another "version" of your App Engine app, then when all modules are deployed, do a very fast version switch?

Versions also allow for traffic splitting if you need/want that kind of thing.