Improvements

shutdown.go

@@ -15,7 +15,7 @@ import (
 //	 log.Println("Shutting down")
 //  })
 type Shutdowner struct {
-	initialized   bool
+	initializer   sync.Once
 	shutdown      bool
 	quit          chan os.Signal
 	funcs         []ShutdownFunc
@@ -29,34 +29,28 @@ type ShutdownFunc func()
 
 // Internal method
 func (f ShutdownFunc) execute(c context.Context) {
-	done := false
+	done := make(chan interface{})
-	// Execute ShutdownFunc in goroutine and set done = true
+	// Execute ShutdownFunc in goroutine and close channel when finished
 	go func() {
 		f()
-		done = true
+		close(done)
 	}()
-	for {
 	// Check if context canceled or ShutdownFunc finished
 	select {
 	case <-c.Done():
 		// Context canceled, return
 		return
-		default:
+	case <-done:
-			if done {
 		// ShutdownFunc finished, return
 		return
 	}
-			// Otherwise continue
-		}
-	}
 }
 
 // Internal method
 func (s *Shutdowner) init() {
-	// Check if already initialized
+	s.initializer.Do(func() {
-	if s.initialized {
+		s.mutex.Lock()
-		return
+		defer s.mutex.Unlock()
-	}
 		// Initialize cancel context and signal channel
 		s.cancelContext, s.cancelFunc = context.WithCancel(context.Background())
 		s.quit = make(chan os.Signal, 2)
@@ -70,8 +64,7 @@ func (s *Shutdowner) init() {
 				s.Shutdown()
 			}
 		}()
-	// Finished
+	})
-	s.initialized = true
 }
 
 // Add a func, that should be called with s.Shutdown() or when receiving a shutdown signal