Merge pull request #16250 from gluk256/317-fatalf

whisper: refactoring go-routines workflow

Move the call mailServer.Init() down (to the bottom of the function) because if the function initialize() completes successfully, then it will be followed by mailServer.Close() in shutdown(). The workflow of the corresponding goroutines is clearer now.

cmd/wnode/main.go

@@ -110,6 +110,7 @@ func main() {
 	processArgs()
 	initialize()
 	run()
+	shutdown()
 }
 
 func processArgs() {
@@ -209,21 +210,6 @@ func initialize() {
 		MinimumAcceptedPOW: *argPoW,
 	}
 
-	if *mailServerMode {
-		if len(msPassword) == 0 {
-			msPassword, err = console.Stdin.PromptPassword("Please enter the Mail Server password: ")
-			if err != nil {
-				utils.Fatalf("Failed to read Mail Server password: %s", err)
-			}
-		}
-
-		shh = whisper.New(cfg)
-		shh.RegisterServer(&mailServer)
-		mailServer.Init(shh, *argDBPath, msPassword, *argServerPoW)
-	} else {
-		shh = whisper.New(cfg)
-	}
-
 	if *argPoW != whisper.DefaultMinimumPoW {
 		err := shh.SetMinimumPoW(*argPoW)
 		if err != nil {
@@ -265,6 +251,26 @@ func initialize() {
 		maxPeers = 800
 	}
 
+	_, err = crand.Read(entropy[:])
+	if err != nil {
+		utils.Fatalf("crypto/rand failed: %s", err)
+	}
+
+	if *mailServerMode {
+		if len(msPassword) == 0 {
+			msPassword, err = console.Stdin.PromptPassword("Please enter the Mail Server password: ")
+			if err != nil {
+				utils.Fatalf("Failed to read Mail Server password: %s", err)
+			}
+		}
+
+		shh = whisper.New(cfg)
+		shh.RegisterServer(&mailServer)
+		mailServer.Init(shh, *argDBPath, msPassword, *argServerPoW)
+	} else {
+		shh = whisper.New(cfg)
+	}
+
 	server = &p2p.Server{
 		Config: p2p.Config{
 			PrivateKey:     nodeid,
@@ -278,17 +284,13 @@ func initialize() {
 			TrustedNodes:   peers,
 		},
 	}
-
-	_, err = crand.Read(entropy[:])
-	if err != nil {
-		utils.Fatalf("crypto/rand failed: %s", err)
-	}
 }
 
-func startServer() {
+func startServer() error {
 	err := server.Start()
 	if err != nil {
-		utils.Fatalf("Failed to start Whisper peer: %s.", err)
+		fmt.Printf("Failed to start Whisper peer: %s.", err)
+		return err
 	}
 
 	fmt.Printf("my public key: %s \n", common.ToHex(crypto.FromECDSAPub(&asymKey.PublicKey)))
@@ -307,6 +309,7 @@ func startServer() {
 	if !*forwarderMode {
 		fmt.Printf("Please type the message. To quit type: '%s'\n", quitCommand)
 	}
+	return nil
 }
 
 func isKeyValid(k *ecdsa.PublicKey) bool {
@@ -420,8 +423,10 @@ func waitForConnection(timeout bool) {
 }
 
 func run() {
-	defer mailServer.Close()
+	err := startServer()
-	startServer()
+	if err != nil {
+		return
+	}
 	defer server.Stop()
 	shh.Start(nil)
 	defer shh.Stop()
@@ -439,8 +444,11 @@ func run() {
 	} else {
 		sendLoop()
 	}
+}
 
+func shutdown() {
 	close(done)
+	mailServer.Close()
 }
 
 func sendLoop() {