feat: Add version package (#143)

Author: ginokent

version/version.go

@@ -0,0 +1,90 @@
+// version package provides build-time version information.
+// It is designed to be used via the -ldflags option of go build.
+//
+// e.g.
+//
+//	go build -ldflags "-X github.com/kunitsucom/util.go/version.version=${BUILD_VERSION} -X github.com/kunitsucom/util.go/version.revision=${BUILD_REVISION} -X github.com/kunitsucom/util.go/version.branch=${BUILD_BRANCH} -X github.com/kunitsucom/util.go/version.timestamp=${BUILD_TIMESTAMP}"
+package version
+
+import (
+	"runtime"
+	"runtime/debug"
+)
+
+//nolint:gochecknoglobals
+var (
+	version   string
+	revision  string
+	branch    string
+	timestamp string
+)
+
+type BuildVersion struct {
+	Version   string `json:"version"`
+	Revision  string `json:"revision"`
+	Branch    string `json:"branch"`
+	Timestamp string `json:"timestamp"`
+	GoVersion string `json:"goVersion"`
+	GOARCH    string `json:"goarch"`
+	GOOS      string `json:"goos"`
+}
+
+func ReadBuildVersion() BuildVersion {
+	return BuildVersion{
+		Version:   Version(),
+		Revision:  Revision(),
+		Branch:    Branch(),
+		Timestamp: Timestamp(),
+		GoVersion: runtime.Version(),
+		GOARCH:    runtime.GOARCH,
+		GOOS:      runtime.GOOS,
+	}
+}
+
+func Version() string {
+	if version != "" {
+		return version
+	}
+
+	if info, ok := debug.ReadBuildInfo(); ok {
+		return info.Main.Version
+	}
+
+	return ""
+}
+
+func Revision() string {
+	if revision != "" {
+		return revision
+	}
+
+	if info, ok := debug.ReadBuildInfo(); ok {
+		for _, setting := range info.Settings {
+			if setting.Key == "vcs.revision" {
+				return setting.Value
+			}
+		}
+	}
+
+	return ""
+}
+
+func Branch() string {
+	return branch
+}
+
+func Timestamp() string {
+	if timestamp != "" {
+		return timestamp
+	}
+
+	if info, ok := debug.ReadBuildInfo(); ok {
+		for _, setting := range info.Settings {
+			if setting.Key == "vcs.time" {
+				return setting.Value
+			}
+		}
+	}
+
+	return ""
+}