How does “go get” get to know what version control system to use with remote repos?


How does “go get” get to know what version control system to use with remote repos?

I am new to golang. I learned that go get serves as a package manager and contact remote repos with various version control systems. 
So, given a package import path, how does go get decide which VCS to use?  I always see below query string in the reqeust:

So seems some protocol/convention here?


Answer 1:

One of the nice things about Go is that everything is in, well, Go 🙂 Including almost all of the standard library and tools.

In cmd/go/vcs.go we can see how this is done, and in cmd/go/alldocs.go it is documented.

Specifically, look at repoRootForImportPath:

// repoRootForImportPath analyzes importPath to determine the
// version control system, and code repository to use.
func repoRootForImportPath(importPath string, security securityMode) (*repoRoot, error) {

What this does is:

  1. vcsPaths holds a static lists of “known hosts”. For some (e.g. GitHub) this is easy and we can just set the VCS. For others (e.g. BitBucket) a callback function is used which examines the URL to see which repo can be used.

  2. If that fails, it tries to look at a “VCS extension” in the path, such as or

  3. And finally go get will look for a go-import meta tag, which looks like:

    <meta name="go-import" content=" git">

    Also see parseMetaGoImports(). Vanity Imports with Hugo is a nice introduction on how to use this.

There is no real “auto-detection” mechanism. So if you repo lives at then go get will not work. You need the extension or meta tags.

The go-get=1 parameter is added so that it’s easy for website builders to see that this is a request from go get, which may be useful in some cases.