finally a proper use for sync.Once

init.go

@@ -23,9 +23,6 @@ func Default(opts ...OptionFunc) *Engine {
 }
 */
 
-// todo: use initOnce
-// cache.go has Do()
-// f.initOnce.Do(f.initWork)
 func Init() *Forge {
 	f := InitPB()
 
@@ -162,6 +159,7 @@ func (f *Forge) RawInitPB() {
 // try to NOT use the ENV settings anywhere but here
 // all initial ENV settings should be stored in the forge struct
 func (f *Forge) setenv() {
+	f.once.Do(func() {
 		if err := fhelp.ConfigureENV(); err != nil {
 			log.Info("forge ConfigureENV() failed", err)
 			os.Exit(-1)
@@ -181,6 +179,7 @@ func (f *Forge) setenv() {
 		log.Printf("FORGE_URL      = %s\n", f.forgeURL)
 		log.Printf("FORGE_PATCHDIR = %s\n", f.patchDir)
 		log.Printf("HOSTNAME       = %s\n", os.Getenv("HOSTNAME"))
+	})
 }
 
 func (f *Forge) GetForgeURL() string {

structs.go

@@ -10,7 +10,7 @@ import (
 // maybe an interface someday?
 type Forge struct {
 	// one-time initialized data
-	initOnce    sync.Once
+	once        sync.Once
 	initErr     error         // init error, if any
 	goSrc       string        // the path to go/src
 	repoPB      string        // the path to the repos.pb cache file