How it works...

The runtime package contains a lot of useful functions. To find out the Go runtime version, the Version function could be used. The documentation states that the function returns the hash of the commit, and the date or tag at the time of the binary build.

The Version function, in fact, returns the runtime/internal/sys .The Version constant. The constant itself is located in the $GOROOT/src/runtime/internal/sys/zversion.go file.

This .go file is generated by the go dist tool and the version is resolved by the findgoversion function in the go/src/cmd/dist/build.go file, as explained next.

The $GOROOT/VERSION takes priority. If the file is empty or does not exist, the $GOROOT/VERSION.cache file is used. If the $GOROOT/VERSION.cache is also not found, the tool tries to resolve the version by using the Git information, but in this case, you need to initialize the Git repository for the Go source.