overlays

[simple perch]

TL;DR:

go build -o .bin/example -overlay overlay.json -gcflags="all=-N -l" ./cmd/server/main.go

overlay.json (paraphrasing)

{
    "Replace": {
        "/.../path/to/file.go": "/.../local/file.go"
    }
}

I got the overlay to work, but ran into a problem where because the overlayed file does not reference a library that the overlay file does, I get this. I'm assuming it has to do with symbol load order or something?

../../../../path/to/file.go:6:2: could not import io (open : no such file or directory)
../../../../path/to/file.go:7:2: could not import net/http (open : no such file or directory)

[snow marsh]

never heard of -overlay before / - what's your objective/problem you're trying to solve with it ?

[simple perch]

Team doesn't want to let me update internal library to allow an exclusion for testing, because "EnVs CoUlD bE sCaRrY", so for localized testing I'm thinking about either:
A. Using an overlay to force it to be mock code
B. Using a replace directive, but then I'd have to mock out the entire freaking library and there are multiple versions and sub folders so it'd be annoying to implement.

Also thinking about build tags and just isolate them behind tagged compilation

[snow marsh]

build tags sounds cleaner, for code you have access to

[simple perch]

It's definitely a hard one because while I have access, it's not easy access to get things merged. Plus then I have to update all consumers

[snow marsh]

you wouldn’t, you would only use tags for your special case and everything else would have default/normal/prod behavior

[simple perch]

For a system that needs all components to spin up locally for localized testing you would; any out of date versions wouldn't support the tag.

Which, for a micro service infrastructure, is like 18 services. Nightmare of a situation.