golang-samples | Sample apps and code | GCP library

I'm trying to deploy an app engine application, but no matter which code I'm trying to deploy, even if it's taken from their samples at:

https://github.com/GoogleCloudPlatform/golang-samples

I get the same error:

I'm following two guides which appear to conflict

1. Standard Go Project Layout
2. Google Cloud Endpoints Sample for Go using gRPC

Go's Standard Go Project Layout recommends a /build directory, the use of which is described as

Packaging and Continuous Integration.

Put your cloud (AMI), container (Docker), OS (deb, rpm, pkg) package configurations and scripts in the /build/package directory.

Following Google Cloud Endpoints Sample for Go using gRPC, I have a Dockerfile which copies application source code and installs any dependencies with go get.

I'm trying to create a bucket in GCP using Go, I tried this create method, that creates a bucket in Go. Here's the go playground of the same. When I try to run it, it just says timeout running go build and Go Build Failed. I know it's trying to download some packages, but not sure why it is getting timed out while downloading the package?. I'm new to Go and wanted to test out how bucket creation works in go. Am I missing something?.

As an alternative to signed urls with a url prefix, I'm trying to get signed cookies working. Google Cloud CDN is setup with a backend bucket which is configured and working for standard signed urls.

Using these Go examples I've implemented a cookie signing function in nodejs(typescript) that when provied with the test sample data produces the expected outcome.