cmd/relaysrv: Add build stamped version, print at startup

cmd/relaysrv/main.go

@@ -13,6 +13,7 @@ import (
 	"os/signal"
 	"path/filepath"
 	"runtime"
+	"strconv"
 	"strings"
 	"sync/atomic"
 	"syscall"
@@ -26,6 +27,24 @@ import (
 	syncthingprotocol "github.com/syncthing/syncthing/lib/protocol"
 )
 
+var (
+	Version    string
+	BuildStamp string
+	BuildUser  string
+	BuildHost  string
+
+	BuildDate   time.Time
+	LongVersion string
+)
+
+func init() {
+	stamp, _ := strconv.Atoi(BuildStamp)
+	BuildDate = time.Unix(int64(stamp), 0)
+
+	date := BuildDate.UTC().Format("2006-01-02 15:04:05 MST")
+	LongVersion = fmt.Sprintf(`relaysrv %s (%s %s-%s) %s@%s %s`, Version, runtime.Version(), runtime.GOOS, runtime.GOARCH, BuildUser, BuildHost, date)
+}
+
 var (
 	listen string
 	debug  bool = false
@@ -82,6 +101,8 @@ func main() {
 		log.Fatal(err)
 	}
 
+	log.Println(LongVersion)
+
 	maxDescriptors, err := osutil.MaximizeOpenFileLimit()
 	if maxDescriptors > 0 {
 		// Assume that 20% of FD's are leaked/unaccounted for.