cleaner handling of socket open

Signed-off-by: Jeff Carr <jcarr@wit.com>

socketWIT.go

@@ -7,6 +7,10 @@ import "net"
 import "fmt"
 import "bufio"
 
+import "github.com/svent/go-nbreader"
+
+import "git.wit.com/jcarr/dnssecsocket"
+
 // import "github.com/gookit/config"
 // import "git.wit.com/wit/gui"
 
@@ -31,15 +35,11 @@ const (
 	CONN_PROTO = "tcp"
 )
 
-func socketToWIT() {
+func socketToWIT(myhostname string) {
 	remoteAddr :=  CONN_HOST + ":" + CONN_PORT
 	log.Println("remoteAddr:", remoteAddr)
 
-	// localAddr :=  "librem15.lab.wit.com" + ":" + CONN_PORT
-	localAddr :=  "[2604:bbc0:3:3:0:10:0:1003]" + ":" + CONN_PORT
-	log.Println("localAddr:", localAddr)
-
-	localTCPAddr, err  := net.ResolveTCPAddr("tcp", localAddr)
+	localTCPAddr := dnssecsocket.ResolveIPv6hostname(myhostname)
 	remoteTCPAddr, err := net.ResolveTCPAddr("tcp", remoteAddr)
 
 	// connect to this socket
@@ -51,22 +51,33 @@ func socketToWIT() {
 		log.Println("socket connect failed. Not sure what to do here. os.Exit() ?")
 		return
 	}
+	defer conn.Close()
 
 	log.Println("socket connected to", CONN_PROTO, CONN_HOST, CONN_PORT)
 
+	fmt.Fprintf(conn, myhostname + "\n")
+
+	connStdin, _ := conn.File()
+
+	go nonBlockingReader(connStdin, os.Stdout)
+
 	// read in input from stdin
 	reader := bufio.NewReader(os.Stdin)
-
-	fmt.Fprintf(conn,"librem15.lab.wit.com\n")
-
 	for {
 		fmt.Print("Text to send: ")
 		text, _ := reader.ReadString('\n')
 		// send to socket
 		fmt.Fprintf(conn, text + "\n")
+		a, err := connStdin.Write([]byte(string(text + "\n")))
+		if (err != nil) {
+			fmt.Println("SOCKET DIED with err=", err, a)
+			return
+		}
+		// TODO: check the socket has died and exit here
+	}
+/*
 		// listen for reply
 
-		newStdin, _ := conn.File()
 		newreader := bufio.NewReader(newStdin)
 
 		for {
@@ -78,6 +89,7 @@ func socketToWIT() {
 			}
 		}
 	}
+*/
 }
 
 func retrySocket() {
@@ -85,6 +97,36 @@ func retrySocket() {
 		log.Println("Sleep for 1 seconds, then try to establish connection to WIT")
 		time.Sleep(1 * 1000 * 1000 * 1000)
 		// for now, loop until I figure out what to actually do
-		socketToWIT()
+		socketToWIT("librem15.lab.wit.com")
+	}
+}
+
+// pass in two file handles (1 read, 1 write)
+func nonBlockingReader(readFileHandle *os.File, writeFileHandle *os.File) {
+	// create a nonblocking GO reader
+	newreader := bufio.NewReader(readFileHandle)
+        nbr := nbreader.NewNBReader(newreader, 1024)
+
+	for {
+		defer readFileHandle.Close()
+		defer writeFileHandle.Close()
+		totalCount := 0
+		for {
+			oneByte := make([]byte, 1024)
+			count, err := nbr.Read(oneByte)
+			if (err != nil) {
+				log.Println("count, err =", count, err)
+				return
+			}
+			totalCount += count
+			if (count == 0) {
+				time.Sleep(20 * time.Millisecond)   // only check the buffer 500 times a second
+				if (totalCount != 0) {
+					log.Println("totalCount = ", totalCount)
+					totalCount = 0
+				}
+			}
+			writeFileHandle.Write([]byte(string(oneByte)))
+		}
 	}
 }