How do I build a static Go binary for the Docker Alpine image?

Question

I want to build a Go 1.9.2 binary and run it on the Docker Alpine image. The Go code I wrote doesn't call any C code. It also uses the net package. Unfortunately it hasn't been as simple as it sounds as Go doesn't seem to quite build static binaries all the time. When I try to execute the binary I often get cryptic messages for why the binary didn't execute. There's quite a bit of information on the internet about this but most of it ends up with people using trial an error to make their binaries work.

So far I have found the following works, however I don't know why, if it is optimal or if it could be simplified.

env GOOS=linux GARCH=amd64 go install -v -a -tags netgo -installsuffix netgo -ldflags "-linkmode external -extldflags -static"

What is the canonical way (if it exists) to build a Go binary that will run on the Alpine 3.7 docker image? I am happy to use apk to install packages to the Alpine image if that would make things more efficient/easier. (Believe I need to install ca-certificates anyway.)

Answer 1

Yes, you often need to add extra resource files like certificates especially when using a minimal distribution like alpine but the fact that you can run go applications on such small distributions is often also seen as an advantage.

To add the certificates this is a really good explanation outlining how to do it on a scratch container:

https://blog.codeship.com/building-minimal-docker-containers-for-go-applications/

If you would rather stick with alpine then you can install this package to get them:

https://pkgs.alpinelinux.org/package/v3.7/main/x86/ca-certificates