There are no plans to migrate all of GitLab to Go. The main Rails app is going to stay a Rails app for the foreseeable future. There are a few reasons for this. For one it'd be such a huge project, but also Rails is working well for us, it's great for our pace of feature development.

We are working on moving the git layer to Gitaly[0] which is written in Go (and is what this blog post is about). It was one of our major bottlenecks and we've seen a lot of benefit from having made the switch. It's not done yet, but a lot of the calls to git that the application makes are now done through Gitaly.

[0]: https://gitlab.com/gitlab-org/gitaly

They have so many features that I don't see it happening ever.