Added fix for RPC port detection

pkg/skaffold/kubernetes/portforward/kubectl_forwarder.go

@@ -91,7 +91,7 @@ func (k *KubectlForwarder) forward(parentCtx context.Context, pfe *portForwardEn
 		}
 		pfe.terminationLock.Unlock()
 
-		if !isPortFree(pfe.localPort) {
+		if !isPortFree(util.Loopback, pfe.localPort) {
 			// Assuming that Skaffold brokered ports don't overlap, this has to be an external process that started
 			// since the dev loop kicked off. We are notifying the user in the hope that they can fix it
 			color.Red.Fprintf(k.out, "failed to port forward %v, port %d is taken, retrying...\n", pfe, pfe.localPort)

pkg/skaffold/kubernetes/portforward/kubectl_forwarder_test.go

@@ -50,7 +50,7 @@ func TestUnavailablePort(t *testing.T) {
 		// has been called
 		var portFreeWG sync.WaitGroup
 		portFreeWG.Add(1)
-		t.Override(&isPortFree, func(int) bool {
+		t.Override(&isPortFree, func(string, int) bool {
 			portFreeWG.Done()
 			return false
 		})

pkg/skaffold/kubernetes/portforward/pod_forwarder.go

@@ -148,7 +148,7 @@ func (p *WatchingPodForwarder) podForwardingEntry(resourceVersion, containerName
 	}
 
 	// retrieve an open port on the host
-	entry.localPort = retrieveAvailablePort(resource.Port.IntVal, &p.entryManager.forwardedPorts)
+	entry.localPort = retrieveAvailablePort(resource.Address, resource.Port.IntVal, &p.entryManager.forwardedPorts)
 
 	return entry, nil
 }

pkg/skaffold/kubernetes/portforward/pod_forwarder_test.go

@@ -31,6 +31,7 @@ import (
 	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/kubernetes"
 	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/schema/latest"
 	schemautil "github.com/GoogleContainerTools/skaffold/pkg/skaffold/schema/util"
+	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/util"
 	"github.com/GoogleContainerTools/skaffold/testutil"
 	testEvent "github.com/GoogleContainerTools/skaffold/testutil/event"
 )
@@ -403,7 +404,7 @@ func TestAutomaticPortForwardPod(t *testing.T) {
 		testutil.Run(t, test.description, func(t *testutil.T) {
 			testEvent.InitializeState([]latest.Pipeline{{}})
 			taken := map[int]struct{}{}
-			t.Override(&retrieveAvailablePort, mockRetrieveAvailablePort(taken, test.availablePorts))
+			t.Override(&retrieveAvailablePort, mockRetrieveAvailablePort(util.Loopback, taken, test.availablePorts))
 			t.Override(&topLevelOwnerKey, func(context.Context, metav1.Object, string) string { return "owner" })
 
 			if test.forwarder == nil {

pkg/skaffold/kubernetes/portforward/port_forward_integration.go

@@ -28,6 +28,7 @@ import (
 	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/kubectl"
 	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/schema/latest"
 	schemautil "github.com/GoogleContainerTools/skaffold/pkg/skaffold/schema/util"
+	"github.com/GoogleContainerTools/skaffold/pkg/skaffold/util"
 )
 
 // SimulateDevCycle is used for testing a port forward + stop + restart in a simulated dev cycle
@@ -37,7 +38,7 @@ func SimulateDevCycle(t *testing.T, kubectlCLI *kubectl.CLI, namespace string) {
 	defer func() { portForwardEvent = portForwardEventHandler }()
 	portForwardEvent = func(entry *portForwardEntry) {}
 	ctx := context.Background()
-	localPort := retrieveAvailablePort(9000, &em.forwardedPorts)
+	localPort := retrieveAvailablePort(util.Loopback, 9000, &em.forwardedPorts)
 	pfe := newPortForwardEntry(0, latest.PortForwardResource{
 		Type:      "deployment",
 		Name:      "leeroy-web",
@@ -50,7 +51,7 @@ func SimulateDevCycle(t *testing.T, kubectlCLI *kubectl.CLI, namespace string) {
 
 	logrus.Info("waiting for the same port to become available...")
 	if err := wait.Poll(100*time.Millisecond, 5*time.Second, func() (done bool, err error) {
-		nextPort := retrieveAvailablePort(localPort, &em.forwardedPorts)
+		nextPort := retrieveAvailablePort(util.Loopback, localPort, &em.forwardedPorts)
 
 		logrus.Infof("next port %d", nextPort)
 

pkg/skaffold/kubernetes/portforward/resource_forwarder.go

@@ -132,7 +132,7 @@ func (p *ResourceForwarder) getCurrentEntry(resource latest.PortForwardResource)
 	if requestPort == 0 && resource.Port.IntVal >= 1024 {
 		requestPort = resource.Port.IntVal
 	}
-	entry.localPort = retrieveAvailablePort(requestPort, &p.entryManager.forwardedPorts)
+	entry.localPort = retrieveAvailablePort(resource.Address, requestPort, &p.entryManager.forwardedPorts)
 	return entry
 }
 

pkg/skaffold/kubernetes/portforward/resource_forwarder_test.go

@@ -64,10 +64,10 @@ func newTestForwarder() *testForwarder {
 	return &testForwarder{}
 }
 
-func mockRetrieveAvailablePort(taken map[int]struct{}, availablePorts []int) func(int, *util.PortSet) int {
+func mockRetrieveAvailablePort(_ string, taken map[int]struct{}, availablePorts []int) func(string, int, *util.PortSet) int {
 	// Return first available port in ports that isn't taken
 	var lock sync.Mutex
-	return func(int, *util.PortSet) int {
+	return func(string, int, *util.PortSet) int {
 		for _, p := range availablePorts {
 			lock.Lock()
 			if _, ok := taken[p]; ok {
@@ -122,7 +122,7 @@ func TestStart(t *testing.T) {
 	for _, test := range tests {
 		testutil.Run(t, test.description, func(t *testutil.T) {
 			testEvent.InitializeState([]latest.Pipeline{{}})
-			t.Override(&retrieveAvailablePort, mockRetrieveAvailablePort(map[int]struct{}{}, test.availablePorts))
+			t.Override(&retrieveAvailablePort, mockRetrieveAvailablePort(util.Loopback, map[int]struct{}{}, test.availablePorts))
 			t.Override(&retrieveServices, func(context.Context, string, []string) ([]*latest.PortForwardResource, error) {
 				return test.resources, nil
 			})
@@ -201,9 +201,9 @@ func TestGetCurrentEntryFunc(t *testing.T) {
 
 	for _, test := range tests {
 		testutil.Run(t, test.description, func(t *testutil.T) {
-			t.Override(&retrieveAvailablePort, func(req int, ps *util.PortSet) int {
+			t.Override(&retrieveAvailablePort, func(addr string, req int, ps *util.PortSet) int {
 				t.CheckDeepEqual(test.expectedReq, req)
-				return mockRetrieveAvailablePort(map[int]struct{}{}, test.availablePorts)(req, ps)
+				return mockRetrieveAvailablePort(util.Loopback, map[int]struct{}{}, test.availablePorts)(addr, req, ps)
 			})
 
 			entryManager := NewEntryManager(ioutil.Discard, newTestForwarder())
@@ -267,7 +267,7 @@ func TestUserDefinedResources(t *testing.T) {
 	for _, test := range tests {
 		testutil.Run(t, test.description, func(t *testutil.T) {
 			testEvent.InitializeState([]latest.Pipeline{{}})
-			t.Override(&retrieveAvailablePort, mockRetrieveAvailablePort(map[int]struct{}{}, []int{8080, 9000}))
+			t.Override(&retrieveAvailablePort, mockRetrieveAvailablePort(util.Loopback, map[int]struct{}{}, []int{8080, 9000}))
 			t.Override(&retrieveServices, func(context.Context, string, []string) ([]*latest.PortForwardResource, error) {
 				return []*latest.PortForwardResource{svc}, nil
 			})

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.GetAvailablePort(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
@@ -88,36 +92,36 @@ func (f *PortSet) List() []int {
 }
 
 // GetAvailablePort returns an available port that is near the requested port when possible.
-// First, check if the provided port is available on the specified address. If so, use it.
+// First, check if the provided port is available on the specified address and INADDR_ANY. If so, use it.
 // If not, check if any of the next 10 subsequent ports are available.
 // If not, check if any of ports 4503-4533 are available.
 // If not, return a random port, which hopefully won't collide with any future containers
 //
 // See https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt
-func GetAvailablePort(port int, usedPorts *PortSet) int {
+func GetAvailablePort(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
 	}
@@ -129,20 +133,29 @@ 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 IsPortFree(address, p)
 }
 
-func IsPortFree(p int) bool {
+func IsPortFree(address string, p int) bool {
+	// Ensure the port is available across all interfaces
 	l, err := net.Listen("tcp", fmt.Sprintf(":%d", p))
-	if err != nil {
+	if err != nil || l == nil {
 		return false
 	}
-
 	l.Close()
+
+	if address != Any {
+		// Ensure the port is available on the specific interface too
+		l, err := net.Listen("tcp", fmt.Sprintf("%s:%d", address, p))
+		if err != nil || l == nil {
+			return false
+		}
+		l.Close()
+	}
 	return true
 }

pkg/skaffold/util/port_test.go

@@ -56,7 +56,7 @@ func TestGetAvailablePort(t *testing.T) {
 	wg.Add(N)
 	for i := 0; i < N; i++ {
 		go func() {
-			port := GetAvailablePort(4503, &ports)
+			port := GetAvailablePort(Loopback, 4503, &ports)
 
 			l, err := net.Listen("tcp", fmt.Sprintf("%s:%d", Loopback, port))
 			if err != nil {