# git-version.go Use git tags to add semver to your go package. ```txt Goal: Either use an exact version like v1.0.0 or translate the git version like v1.0.0-4-g0000000 to a semver like v1.0.1-pre4+g0000000 Fail gracefully when git repo isn't available. ``` # Demo Generate an `xversion.go` file: ```bash go run git.rootprojects.org/root/go-gitver cat xversion.go ``` **Note**: The file is named `xversion.go` by default so that the generated file's `init()` will come later, and thus take priority, over most other files. See `go-gitver`s self-generated version: ```bash go run git.rootprojects.org/root/go-gitver version ``` # QuickStart Add this to the top of your main file: ```go //go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver ``` Add a file that imports go-gitver (for versioning) ```go // +build tools package example import _ "git.rootprojects.org/root/go-gitver" ``` Change you build instructions to be something like this: ```bash go mod vendor go generate -mod=vendor ./... go build -mod=vendor -o example cmd/example/*.go ``` You don't have to use `mod vendor`, but I highly recommend it. # Options ``` version print version and exit --fail exit with non-zero status code on failure --package will set the package name --outfile will replace `xversion.go` with the given file path ``` ENVs ``` # Alias for --fail GITVER_FAIL=true ``` For example: ```go //go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver --fail ``` ```bash go run -mod=vendor git.rootprojects.org/root/go-gitver version ``` # Usage See `examples/basic` 1. Create a `tools` package in your project 2. Guard it against regular builds with `// +build tools` 3. Include `_ "git.rootprojects.org/root/go-gitver"` in the imports 4. Declare `var GitRev, GitVersion, GitTimestamp string` in your `package main` 5. Include `//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver` as well `tools/tools.go`: ```go // +build tools // This is a dummy package for build tooling package tools import ( _ "git.rootprojects.org/root/go-gitver" ) ``` `main.go`: ```go //go:generate go run git.rootprojects.org/root/go-gitver --fail package main import "fmt" var ( GitRev = "0000000" GitVersion = "v0.0.0-pre0+0000000" GitTimestamp = "0000-00-00T00:00:00+0000" ) func main() { fmt.Println(GitRev) fmt.Println(GitVersion) fmt.Println(GitTimestamp) } ``` If you're using `go mod vendor` (which I highly recommend that you do), you'd modify the `go:generate` ever so slightly: ```go //go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver --fail ``` The only reason I didn't do that in the example is that I'd be included the repository in itself and that would be... weird. # Why a tools package? > import "git.rootprojects.org/root/go-gitver" is a program, not an importable package Having a tools package with a build tag that you don't use is a nice way to add exact versions of a command package used for tooling to your `go.mod` with `go mod tidy`, without getting the error above. # git: behind the curtain These are the commands that are used under the hood to produce the versions. Shows the git tag + description. Assumes that you're using the semver format `v1.0.0` for your base tags. ```bash git describe --tags --dirty --always # v1.0.0 # v1.0.0-1-g0000000 # v1.0.0-dirty ``` Show the commit date (when the commit made it into the current tree). Internally we use the current date when the working tree is dirty. ```bash git show v1.0.0-1-g0000000 --format=%cd --date=format:%Y-%m-%dT%H:%M:%SZ%z --no-patch # 2010-01-01T20:30:00Z-0600 # fatal: ambiguous argument 'v1.0.0-1-g0000000-dirty': unknown revision or path not in the working tree. ``` Shows the most recent commit. ```bash git rev-parse HEAD # 0000000000000000000000000000000000000000 ```