Modules and Creating Better Packages

Modules

A Go module is similar to a Go package, but Go modules are versioned and can include multiple packages. Go uses semantic versioning for versioning modules. This means that versions begin with the letter v, followed by the major.minor.patch version numbers. Therefore, we can have versions such as v1.0.0, v1.0.5, and v2.0.2. The v1, v2, and v3 parts signify the major version of a Go package that is usually not backward compatible. This means that if our Go program works with v1, it will not necessarily work with v2 or v3—it might work, but we can’t count on it. The second number in a version is about features. Usually, v1.1.0 has more features than v1.0.2 or v1.0.0 while being compatible with all older versions. Lastly, the third number is just about bug fixes without having any new features. Note that semantic versioning is also used for Go versions.

Note: Go modules were introduced in Go v1.11 but were finalized in Go v1.13.

If you want to learn more about modules, you can read the five-part series of blog posts on using Go modules, as well as the official document on developing and publishing Go modules. Just remember that a Go module is similar but not identical to a regular Go package with a version and that a module can consist of multiple packages.