1. Why do you have mulitple go.mod files? (Are you versioning the modules separately?) In most cases it's simpler to have a single module per repository.

2. Please distill your example down to the actual go commands involved, without the Docker boilerplate. If you figure out the correct go commands to run, then that should be straightforward to translate that into a dockerfile, but trying to do both at once makes the example much more difficult to follow.

3. Unless I'm mistaken, it looks like you're combining commands in GOPATH mode (go get and go install) with one in module mode (go build). The long-term plan is to replace GOPATH mode completely, so if you're planning to use module mode it's much clearer to use it consistently from the start.

@marc-hybridblock

but i can make it run using go module if im using my sub package within the service

I'm assuming this means that it builds when you run go build locally on your machine inside the green directory. If that is correct, then the build failure stems from the

COPY ./green /srv/green

This is because when go build builds it uses the import path to either locate dependencies or sub packages. By copying the green directory, which is apart of the path github.com/product/color/green, into /srv/green/ you change the import paths without changing them in the source. The build output shows this with

cannot find module for path github.com/product/color/green/lib

The above message occurs because the Dockerfile COPY changes the location of the green package from github.com/product/color/green/lib to srv/green/lib, which is obviously not the root path for the lib sub package mentioned in the build failure.

To resolve this I recommend not build locally i.e. no COPY and instead go get the sub module you want. This solution is especially nice, since go get will also build the module after retrieving it so no go build has to be run. However, if building locally is desired I'd recommend copying your sub module directory-for-directory into Docker, as to avoid any unresolvable import paths.

Timed out in state WaitingForInfo. Closing.

(I am just a bot, though. Please speak up if this is a mistake or you have the requested information.)