refactor!: RunUntilStopped now accepts a chan <-struct{} instead of c…

…han <-interface{} (#33)

Actually achieving what's described in
#32 (comment)
 returns a  and not a ...

golang/server/server.go

@@ -36,9 +36,10 @@ func (server MinimalGRPCServer) RunUntilInterrupted() error {
 	// Signals are used to interrupt the server, so we catch them here
 	termSignalChan := make(chan os.Signal, 1)
 	signal.Notify(termSignalChan, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
-	serverStopChan := make(chan interface{}, 1)
+	serverStopChan := make(chan struct{}, 1)
 	go func() {
-		interruptSignal := <-termSignalChan
+		<-termSignalChan
+		interruptSignal := struct{}{}
 		serverStopChan <- interruptSignal
 	}()
 	if err := server.RunUntilStopped(serverStopChan); err != nil {
@@ -48,7 +49,7 @@ func (server MinimalGRPCServer) RunUntilInterrupted() error {
 }
 
 // Runs the server synchronously until a signal is received on the given channel
-func (server MinimalGRPCServer) RunUntilStopped(stopper <-chan interface{}) error {
+func (server MinimalGRPCServer) RunUntilStopped(stopper <-chan struct{}) error {
 	loggingInterceptorFunc := func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
 		grpcMethod := info.FullMethod
 		logrus.Debugf("Received gRPC request to method '%v' with args:\n%+v", grpcMethod, req)

golang/server/server_test.go

@@ -8,32 +8,32 @@ import (
 )
 
 const (
-	listenPort = uint16(9003)
+	listenPort      = uint16(9003)
 	stopGracePeriod = 10 * time.Second
 )
 
 func TestManualShutdown(t *testing.T) {
 	server := NewMinimalGRPCServer(listenPort, stopGracePeriod, []func(*grpc.Server){})
 
-	stopChan := make(chan interface{})
+	stopChan := make(chan struct{})
 	runResultChan := make(chan error)
 	go func() {
 		runResultChan <- server.RunUntilStopped(stopChan)
 	}()
 	select {
-	case err := <- runResultChan:
+	case err := <-runResultChan:
 		t.Fatalf("The server unexpectedly returned a result before we sent a signal to stop it:\n%v", err)
-	case <- time.After(1 * time.Second):
+	case <-time.After(1 * time.Second):
 		// Nothing
 	}
-	stopChan <- "Stop now"
+	stopChan <- struct{}{}
 
 	maxWaitForServerToStop := 1 * time.Second
 	var errAfterStop error
 	select {
-	case errAfterStop = <- runResultChan:
+	case errAfterStop = <-runResultChan:
 		// Assignment is all we have to do
-	case <- time.After(maxWaitForServerToStop):
+	case <-time.After(maxWaitForServerToStop):
 		t.Fatalf("Expected the server to have stopped after %v, but it didn't", maxWaitForServerToStop)
 	}
 	assert.NoError(t, errAfterStop, "Expected the server to exit without an error but it threw the following:\n%v", errAfterStop)