initial commit

go.mod

@@ -0,0 +1,3 @@
+module git.milar.in/milarin/buildinfo
+
+go 1.19

version.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"runtime/debug"
+)
+
+var (
+	Name      string = ""
+	Version   string = ""
+	Commit    string = ""
+	BuildTime string = ""
+	OS        string = ""
+	Arch      string = ""
+	ShowDeps  bool   = false
+
+	dependencies = []string{}
+)
+
+func main() {
+	Print()
+}
+
+func Fprint(w io.Writer) {
+	if OS == "" || Arch == "" || ShowDeps {
+		fillDebugInfo()
+	}
+
+	if Name == "" {
+		return
+	}
+
+	if Version != "" {
+		fmt.Fprintf(w, "%s %s (built for %s/%s at %s)\n", Name, Version, OS, Arch, BuildTime)
+	} else if Commit != "" {
+		fmt.Fprintf(w, "%s (commit %s) (built at %s)\n", Name, Commit, BuildTime)
+	}
+
+	if ShowDeps {
+		fmt.Println("\ndependencies:")
+		for _, dep := range dependencies {
+			fmt.Fprintf(w, "  %s\n", dep)
+		}
+	}
+}
+
+func Print() {
+	Fprint(os.Stdout)
+}
+
+func overwriteValueIfEmpty(value *string, newValue string) {
+	if *value == "" {
+		*value = newValue
+	}
+}
+
+func fillDebugInfo() {
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return
+	}
+
+	for _, setting := range info.Settings {
+		switch setting.Key {
+		case "GOOS":
+			overwriteValueIfEmpty(&OS, setting.Value)
+		case "GOARCH":
+			overwriteValueIfEmpty(&Arch, setting.Value)
+		case "vcs.revision":
+			overwriteValueIfEmpty(&Commit, setting.Value)
+		}
+	}
+
+	for _, dep := range info.Deps {
+		str := fmt.Sprintf("%s %s", dep.Path, dep.Version)
+		dependencies = append(dependencies, str)
+	}
+}