go-gitver/README.md

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# git-version.go
Use git tags to add semver to your go package.
> 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
```bash
go run git.rootprojects.org/root/go-gitver
```
# 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 -mod=vendor git.rootprojects.org/root/go-gitver
package main
import "fmt"
var (
GitRev = "0000000"
GitVersion = "v0.0.0-pre0+g0000000"
GitTimestamp = "0000-00-00T00:00:00+0000"
)
func main() {
fmt.Println(GitRev)
fmt.Println(GitVersion)
fmt.Println(GitTimestamp)
}
```
# 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
```