Merge pull request #70931 from m1kola/port-forward-consistency

Fixes inconsistent behaviour in portforward

pkg/kubectl/cmd/portforward/portforward.go

@@ -120,7 +120,7 @@ func NewCmdPortForward(f cmdutil.Factory, streams genericclioptions.IOStreams) *
 		},
 	}
 	cmdutil.AddPodRunningTimeoutFlag(cmd, defaultPodPortForwardWaitTimeout)
-	cmd.Flags().StringSliceVar(&opts.Address, "address", []string{"localhost"}, "Addresses to listen on (comma separated)")
+	cmd.Flags().StringSliceVar(&opts.Address, "address", []string{"localhost"}, "Addresses to listen on (comma separated). Only accepts IP addresses or localhost as a value. When localhost is supplied, kubectl will try to bind on both 127.0.0.1 and ::1 and will fail if neither of these addresses are available to bind.")
 	// TODO support UID
 	return cmd
 }

staging/src/k8s.io/client-go/tools/portforward/portforward.go

@@ -23,6 +23,7 @@ import (
 	"io/ioutil"
 	"net"
 	"net/http"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -122,10 +123,14 @@ func parseAddresses(addressesToParse []string) ([]listenAddress, error) {
 	parsed := make(map[string]listenAddress)
 	for _, address := range addressesToParse {
 		if address == "localhost" {
-			ip := listenAddress{address: "127.0.0.1", protocol: "tcp4", failureMode: "all"}
+			if _, exists := parsed["127.0.0.1"]; !exists {
-			parsed[ip.address] = ip
+				ip := listenAddress{address: "127.0.0.1", protocol: "tcp4", failureMode: "all"}
-			ip = listenAddress{address: "::1", protocol: "tcp6", failureMode: "all"}
+				parsed[ip.address] = ip
-			parsed[ip.address] = ip
+			}
+			if _, exists := parsed["::1"]; !exists {
+				ip := listenAddress{address: "::1", protocol: "tcp6", failureMode: "all"}
+				parsed[ip.address] = ip
+			}
 		} else if net.ParseIP(address).To4() != nil {
 			parsed[address] = listenAddress{address: address, protocol: "tcp4", failureMode: "any"}
 		} else if net.ParseIP(address) != nil {
@@ -140,6 +145,9 @@ func parseAddresses(addressesToParse []string) ([]listenAddress, error) {
 		addresses[id] = v
 		id++
 	}
+	// Sort addresses before returning to get a stable order
+	sort.Slice(addresses, func(i, j int) bool { return addresses[i].address < addresses[j].address })
+
 	return addresses, nil
 }
 

staging/src/k8s.io/client-go/tools/portforward/portforward_test.go

@@ -83,6 +83,62 @@ func TestParsePortsAndNew(t *testing.T) {
 				{protocol: "tcp6", address: "::1", failureMode: "all"},
 			},
 		},
+		{
+			input:     []string{"5000:5000"},
+			addresses: []string{"localhost", "::1"},
+			expectedPorts: []ForwardedPort{
+				{5000, 5000},
+			},
+			expectedAddresses: []listenAddress{
+				{protocol: "tcp4", address: "127.0.0.1", failureMode: "all"},
+				{protocol: "tcp6", address: "::1", failureMode: "any"},
+			},
+		},
+		{
+			input:     []string{"5000:5000"},
+			addresses: []string{"localhost", "127.0.0.1", "::1"},
+			expectedPorts: []ForwardedPort{
+				{5000, 5000},
+			},
+			expectedAddresses: []listenAddress{
+				{protocol: "tcp4", address: "127.0.0.1", failureMode: "any"},
+				{protocol: "tcp6", address: "::1", failureMode: "any"},
+			},
+		},
+		{
+			input:     []string{"5000:5000"},
+			addresses: []string{"localhost", "127.0.0.1", "10.10.10.1"},
+			expectedPorts: []ForwardedPort{
+				{5000, 5000},
+			},
+			expectedAddresses: []listenAddress{
+				{protocol: "tcp4", address: "127.0.0.1", failureMode: "any"},
+				{protocol: "tcp6", address: "::1", failureMode: "all"},
+				{protocol: "tcp4", address: "10.10.10.1", failureMode: "any"},
+			},
+		},
+		{
+			input:     []string{"5000:5000"},
+			addresses: []string{"127.0.0.1", "::1", "localhost"},
+			expectedPorts: []ForwardedPort{
+				{5000, 5000},
+			},
+			expectedAddresses: []listenAddress{
+				{protocol: "tcp4", address: "127.0.0.1", failureMode: "any"},
+				{protocol: "tcp6", address: "::1", failureMode: "any"},
+			},
+		},
+		{
+			input:     []string{"5000:5000"},
+			addresses: []string{"10.0.0.1", "127.0.0.1"},
+			expectedPorts: []ForwardedPort{
+				{5000, 5000},
+			},
+			expectedAddresses: []listenAddress{
+				{protocol: "tcp4", address: "10.0.0.1", failureMode: "any"},
+				{protocol: "tcp4", address: "127.0.0.1", failureMode: "any"},
+			},
+		},
 		{
 			input:     []string{"5000", "5000:5000", "8888:5000", "5000:8888", ":5000", "0:5000"},
 			addresses: []string{"127.0.0.1", "::1"},