Use semantic versioning to enable ingress class support

pkg/provider/kubernetes/ingress/client.go

@@ -5,11 +5,11 @@ import (
 	"errors"
 	"fmt"
 	"io/ioutil"
-	"strconv"
 	"time"
 
 	"github.com/containous/traefik/v2/pkg/log"
 	"github.com/golang/protobuf/proto"
+	"github.com/hashicorp/go-version"
 	corev1 "k8s.io/api/core/v1"
 	extensionsv1beta1 "k8s.io/api/extensions/v1beta1"
 	networkingv1beta1 "k8s.io/api/networking/v1beta1"
@@ -55,7 +55,7 @@ type Client interface {
 	GetSecret(namespace, name string) (*corev1.Secret, bool, error)
 	GetEndpoints(namespace, name string) (*corev1.Endpoints, bool, error)
 	UpdateIngressStatus(ing *networkingv1beta1.Ingress, ip, hostname string) error
-	GetServerVersion() (major, minor int, err error)
+	GetServerVersion() (*version.Version, error)
 }
 
 type clientWrapper struct {
@@ -163,13 +163,13 @@ func (c *clientWrapper) WatchAll(namespaces []string, stopCh <-chan struct{}) (<
 		}
 	}
 
-	// If the kubernetes cluster is v1.18+, we can use the new IngressClass objects
+	serverVersion, err := c.GetServerVersion()
-	major, minor, err := c.GetServerVersion()
 	if err != nil {
-		return nil, err
+		log.WithoutContext().Errorf("Failed to get server version: %v", err)
+		return eventCh, nil
 	}
 
-	if major >= 1 && minor >= 18 {
+	if supportsIngressClass(serverVersion) {
 		c.clusterFactory = informers.NewSharedInformerFactoryWithOptions(c.clientset, resyncPeriod)
 		c.clusterFactory.Networking().V1beta1().IngressClasses().Informer().AddEventHandler(eventHandler)
 		c.clusterFactory.Start(stopCh)
@@ -381,23 +381,13 @@ func (c *clientWrapper) newResourceEventHandler(events chan<- interface{}) cache
 }
 
 // GetServerVersion returns the cluster server version, or an error.
-func (c *clientWrapper) GetServerVersion() (major, minor int, err error) {
+func (c *clientWrapper) GetServerVersion() (*version.Version, error) {
-	version, err := c.clientset.Discovery().ServerVersion()
+	serverVersion, err := c.clientset.Discovery().ServerVersion()
 	if err != nil {
-		return 0, 0, fmt.Errorf("could not determine cluster API version: %w", err)
+		return nil, fmt.Errorf("could not retrieve server version: %w", err)
 	}
 
-	major, err = strconv.Atoi(version.Major)
+	return version.NewVersion(serverVersion.GitVersion)
-	if err != nil {
-		return 0, 0, fmt.Errorf("could not determine cluster major API version: %w", err)
-	}
-
-	minor, err = strconv.Atoi(version.Minor)
-	if err != nil {
-		return 0, 0, fmt.Errorf("could not determine cluster minor API version: %w", err)
-	}
-
-	return major, minor, nil
 }
 
 // eventHandlerFunc will pass the obj on to the events channel or drop it.
@@ -432,3 +422,11 @@ func (c *clientWrapper) isWatchedNamespace(ns string) bool {
 	}
 	return false
 }
+
+// IngressClass objects are supported since Kubernetes v1.18.
+// See https://kubernetes.io/docs/concepts/services-networking/ingress/#ingress-class
+func supportsIngressClass(serverVersion *version.Version) bool {
+	ingressClassVersion := version.Must(version.NewVersion("1.18"))
+
+	return ingressClassVersion.LessThanOrEqual(serverVersion)
+}

pkg/provider/kubernetes/ingress/client_mock_test.go

@@ -5,6 +5,7 @@ import (
 	"io/ioutil"
 
 	"github.com/containous/traefik/v2/pkg/provider/kubernetes/k8s"
+	"github.com/hashicorp/go-version"
 	corev1 "k8s.io/api/core/v1"
 	extensionsv1beta1 "k8s.io/api/extensions/v1beta1"
 	"k8s.io/api/networking/v1beta1"
@@ -20,8 +21,7 @@ type clientMock struct {
 	endpoints    []*corev1.Endpoints
 	ingressClass *networkingv1beta1.IngressClass
 
-	serverMajor int
+	serverVersion *version.Version
-	serverMinor int
 
 	apiServiceError       error
 	apiSecretError        error
@@ -31,11 +31,10 @@ type clientMock struct {
 	watchChan chan interface{}
 }
 
-func newClientMock(major, minor int, paths ...string) clientMock {
+func newClientMock(serverVersion string, paths ...string) clientMock {
-	c := clientMock{
+	c := clientMock{}
-		serverMajor: major,
+
-		serverMinor: minor,
+	c.serverVersion = version.Must(version.NewVersion(serverVersion))
-	}
 
 	for _, path := range paths {
 		yamlContent, err := ioutil.ReadFile(path)
@@ -75,8 +74,8 @@ func (c clientMock) GetIngresses() []*v1beta1.Ingress {
 	return c.ingresses
 }
 
-func (c clientMock) GetServerVersion() (major, minor int, err error) {
+func (c clientMock) GetServerVersion() (*version.Version, error) {
-	return c.serverMajor, c.serverMinor, nil
+	return c.serverVersion, nil
 }
 
 func (c clientMock) GetService(namespace, name string) (*corev1.Service, bool, error) {

pkg/provider/kubernetes/ingress/kubernetes.go

@@ -183,7 +183,7 @@ func (p *Provider) loadConfigurationFromIngresses(ctx context.Context, client Cl
 		TCP: &dynamic.TCPConfiguration{},
 	}
 
-	major, minor, err := client.GetServerVersion()
+	serverVersion, err := client.GetServerVersion()
 	if err != nil {
 		log.FromContext(ctx).Errorf("Failed to get server version: %v", err)
 		return conf
@@ -191,7 +191,7 @@ func (p *Provider) loadConfigurationFromIngresses(ctx context.Context, client Cl
 
 	var ingressClass *networkingv1beta1.IngressClass
 
-	if major >= 1 && minor >= 18 {
+	if supportsIngressClass(serverVersion) {
 		ic, err := client.GetIngressClass()
 		if err != nil {
 			log.FromContext(ctx).Errorf("Failed to find an ingress class: %v", err)

pkg/provider/kubernetes/ingress/kubernetes_test.go

@@ -24,10 +24,10 @@ func Bool(v bool) *bool { return &v }
 
 func TestLoadConfigurationFromIngresses(t *testing.T) {
 	testCases := []struct {
-		desc         string
+		desc          string
-		ingressClass string
+		ingressClass  string
-		serverMinor  int
+		serverVersion string
-		expected     *dynamic.Configuration
+		expected      *dynamic.Configuration
 	}{
 		{
 			desc: "Empty ingresses",
@@ -925,8 +925,8 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 			},
 		},
 		{
-			desc:        "v18 Ingress with ingressClass",
+			desc:          "v18 Ingress with ingressClass",
-			serverMinor: 18,
+			serverVersion: "v1.18",
 			expected: &dynamic.Configuration{
 				TCP: &dynamic.TCPConfiguration{},
 				HTTP: &dynamic.HTTPConfiguration{
@@ -953,8 +953,8 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 			},
 		},
 		{
-			desc:        "v18 Ingress with missing ingressClass",
+			desc:          "v18 Ingress with missing ingressClass",
-			serverMinor: 18,
+			serverVersion: "v1.18",
 			expected: &dynamic.Configuration{
 				TCP: &dynamic.TCPConfiguration{},
 				HTTP: &dynamic.HTTPConfiguration{
@@ -993,12 +993,12 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 				paths = append(paths, generateTestFilename("_ingressclass", test.desc))
 			}
 
-			serverMinor := 17
+			serverVersion := test.serverVersion
-			if test.serverMinor != 0 {
+			if serverVersion == "" {
-				serverMinor = test.serverMinor
+				serverVersion = "v1.17"
 			}
 
-			clientMock := newClientMock(1, serverMinor, paths...)
+			clientMock := newClientMock(serverVersion, paths...)
 
 			p := Provider{IngressClass: test.ingressClass}
 			conf := p.loadConfigurationFromIngresses(context.Background(), clientMock)