Initial commit

Author: yitsushi

error.go

@@ -0,0 +1,7 @@
+package build
+
+type BuildInfoError struct{}
+
+func (e BuildInfoError) Error() string {
+	return "unable to read build information"
+}

go.mod

@@ -0,0 +1,3 @@
+module github.com/go-asset/build
+
+go 1.18

main.go

@@ -0,0 +1,68 @@
+package build
+
+import (
+	"fmt"
+	"runtime/debug"
+	"strings"
+)
+
+// VersionInformation contains everything we know about our appliation.
+//
+// Actually, that's a lie, it does not contain everything (yet), but contains
+// a lot of information.
+type VersionInformation struct {
+	AppName  string
+	Version  string
+	Time     string
+	Revision string
+	Dirty    bool
+}
+
+func (info VersionInformation) String() string {
+	parts := []string{}
+
+	if info.AppName != "" {
+		parts = append(parts, info.AppName)
+	}
+
+	if info.Version != "" {
+		parts = append(parts, info.Version)
+	} else if info.Revision != "" {
+		parts = append(parts, info.Revision)
+	}
+
+	if info.Dirty {
+		parts = append(parts, "*dirty*")
+	}
+
+	if info.Time != "" {
+		parts = append(parts, fmt.Sprintf("(%s)", info.Time))
+	}
+
+	return strings.Join(parts, " ")
+}
+
+// ReadVersion reads build information and tried to create a VersionInformation
+// out of it.
+func ReadVersion(appName string) (VersionInformation, error) {
+	version := VersionInformation{AppName: appName}
+
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return version, BuildInfoError{}
+	}
+
+	for _, setting := range info.Settings {
+		if setting.Key == "-ldflags" && strings.HasPrefix(setting.Value, "-buildid=") {
+			version.Version = strings.TrimPrefix(setting.Value, "-buildid=")
+		} else if setting.Key == "vcs.revision" {
+			version.Revision = setting.Value
+		} else if setting.Key == "vcs.time" {
+			version.Time = setting.Value
+		} else if setting.Key == "vcs.modified" {
+			version.Dirty = true
+		}
+	}
+
+	return version, nil
+}