Added fix for RPC port detection

pkg/skaffold/server/server.go

@@ -242,7 +242,7 @@ func errorHandler(ctx context.Context, _ *runtime.ServeMux, marshaler runtime.Ma
 
 func listenOnAvailablePort(preferredPort int, usedPorts *util.PortSet) (net.Listener, int, error) {
 	for try := 1; ; try++ {
-		port := util.GetAvailablePort(preferredPort, usedPorts)
+		port := util.GetAvailablePortWithAddress(util.Loopback, preferredPort, usedPorts)
 
 		l, err := net.Listen("tcp", fmt.Sprintf("%s:%d", util.Loopback, port))
 		if err != nil {

pkg/skaffold/util/port.go

@@ -29,6 +29,10 @@ import (
 // unless we really want to expose something to the network.
 const Loopback = "127.0.0.1"
 
+// Network address which represent any address. This is the default that
+// we should use when checking if port is free.
+const Any = ""
+
 type PortSet struct {
 	ports map[int]bool
 	lock  sync.Mutex
@@ -95,29 +99,34 @@ func (f *PortSet) List() []int {
 //
 // See https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt
 func GetAvailablePort(port int, usedPorts *PortSet) int {
+	// We map this to allow
+	return GetAvailablePortWithAddress(Any, port, usedPorts)
+}
+
+func GetAvailablePortWithAddress(address string, port int, usedPorts *PortSet) int {
 	if port > 0 {
-		if getPortIfAvailable(port, usedPorts) {
+		if getPortIfAvailable(address, port, usedPorts) {
 			return port
 		}
 
 		// try the next 10 ports after the provided one
 		for i := 0; i < 10; i++ {
 			port++
-			if getPortIfAvailable(port, usedPorts) {
+			if getPortIfAvailable(address, port, usedPorts) {
 				logrus.Debugf("found open port: %d", port)
 				return port
 			}
 		}
 	}
 
 	for port = 4503; port <= 4533; port++ {
-		if getPortIfAvailable(port, usedPorts) {
+		if getPortIfAvailable(address, port, usedPorts) {
 			logrus.Debugf("found open port: %d", port)
 			return port
 		}
 	}
 
-	l, err := net.Listen("tcp", ":0")
+	l, err := net.Listen("tcp", fmt.Sprintf("%s:0", address))
 	if err != nil {
 		return -1
 	}
@@ -129,16 +138,20 @@ func GetAvailablePort(port int, usedPorts *PortSet) int {
 	return p
 }
 
-func getPortIfAvailable(p int, usedPorts *PortSet) bool {
+func getPortIfAvailable(address string, p int, usedPorts *PortSet) bool {
 	if alreadySet := usedPorts.LoadOrSet(p); alreadySet {
 		return false
 	}
 
-	return IsPortFree(p)
+	return IsPortFreeWithAddress(address, p)
 }
 
 func IsPortFree(p int) bool {
-	l, err := net.Listen("tcp", fmt.Sprintf(":%d", p))
+	return IsPortFreeWithAddress(Any, p)
+}
+
+func IsPortFreeWithAddress(address string, p int) bool {
+	l, err := net.Listen("tcp", fmt.Sprintf("%s:%d", address, p))
 	if err != nil {
 		return false
 	}