1 files changed, 95 insertions, 0 deletions
diff --git a/pkg/config/version/genver/main.go b/pkg/config/version/genver/main.go
new file mode 100644
index 0000000..e0d80b0
--- /dev/null
+++ b/pkg/config/version/genver/main.go
@@ -0,0 +1,95 @@
+package main
+
+import (
+	"flag"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"text/template"
+	"time"
+)
+
+var (
+	flPackageName  = flag.String("package", "version", "name for the generated golang package")
+	flVariableName = flag.String("variable", "VERSION", "variable name in the generated golang package")
+	flOutputFile   = flag.String("output", "", "output filename (default stdout)")
+)
+
+func main() {
+	flag.Parse()
+	dir := "."
+	if flag.NArg() > 0 {
+		dir = flag.Args()[0]
+	}
+	dir, err := filepath.Abs(dir)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var output io.Writer
+	if len(*flOutputFile) > 0 {
+		fh, err := os.Create(*flOutputFile)
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer fh.Close()
+		output = fh
+	} else {
+		output = os.Stdout
+	}
+
+	vers, err := GitDescribe(dir)
+	if err != nil {
+		log.Fatal(err)
+	}
+	vp := VersionPackage{
+		Name:     *flPackageName,
+		Path:     dir,
+		Date:     time.Now(),
+		Variable: *flVariableName,
+		Version:  vers,
+	}
+
+	packageTemplate.Execute(output, vp)
+}
+
+// VersionPackage is the needed information to template a version package
+type VersionPackage struct {
+	Name     string
+	Path     string
+	Date     time.Time
+	Variable string
+	Version  string
+}
+
+var packageTemplate = template.Must(template.New("default").Parse(packageLayout))
+var packageLayout = `package {{.Name}}
+// AUTO-GENERATED. DO NOT EDIT
+// {{.Date}}
+
+// {{.Variable}} is generated by git-describe from gen.go
+var {{.Variable}} = "{{.Version}}"
+ `
+
+// GitDescribe calls `git describe` in the provided path
+func GitDescribe(path string) (string, error) {
+	cwd, err := os.Getwd()
+	if err != nil {
+		return "", err
+	}
+	// TODO check if this is a directory
+	if err := os.Chdir(path); err != nil {
+		return "", err
+	}
+	defer os.Chdir(cwd)
+
+	buf, err := exec.Command("git", "describe").CombinedOutput()
+	if err != nil {
+		return "", err
+	}
+
+	return strings.TrimSpace(string(buf)), nil
+}