extract VCS branch name used during build

[quin...@gmail.com]

Hi,

I would like to be able to extract the VCS branch name used during build.

Currently I append "-X main.BranchName=${BRANCH}" to the build line which works, but I was hoping there might be a cunning way to extract this from runtime/debug?

Thanks,

-Steve

[Chris Burkert]

You can use go:generate and go:embed to achieve this. In our CI/CD pipeline we generate a json file with a lot of information like vcs, branch, tag, date and time, hash and a lot more. Then we embed this json into the binary.

I became aware of this technique from 

https://levelup.gitconnected.com/a-better-way-than-ldflags-to-add-a-build-version-to-your-go-binaries-2258ce419d2d?gi=c2bc81346d42.

Hope this helps.

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[Duncan Harris]

Do you really need the branch? You get the commit hash for free since Go 1.18 : https://tip.golang.org/doc/go1.18#go-version
You can see the embedded version information with: go version -m <executable_file>

[Tobias Klausmann]

Hi!

Indeed there is. On top of the already mentioned approaches using go
generate, the runtime/debug package:

```
import "runtime/debug"

var Commit = func() string {
if info, ok := debug.ReadBuildInfo(); ok {
for _, setting := range info.Settings {
if setting.Key == "vcs.revision" {
return setting.Value
}
}
}
return ""
}()
```

(shamelessly stolen from
https://icinga.com/blog/2022/05/25/embedding-git-commit-information-in-go-binaries/)

HTH,
Tobias

[quin...@gmail.com]

Thanks for the ideas all, I think go embed is the best path for me.

runtime/debug will give me the revision but sadly it can't give me the branch.

I want the branch as we run a microservice architecture and seeing that all the microservices are running

the release branch and not master (or main) is a useful cross check for our QA dept; we have had cases of

them spending time checking development code which is - well, imperfect.

-Steve