ingress: don't error if candidate group version is not available

pkg/errcode/errcode.go

@@ -113,10 +113,6 @@ const (
 
 	// ErrUnmarshallingKubernetesResource indicates that a Kubernetes resource could not be unmarshalled
 	ErrUnmarshallingKubernetesResource
-
-	// ErrGettingSupportedIngressVersions indicates the mapping of Ingress API versions to the corresponding values indicating
-	// if they are supported could not be configured
-	ErrGettingSupportedIngressVersions
 )
 
 // Range 4000-4100 reserved for errors related to certificate providers
@@ -549,10 +545,6 @@ A Kubernetes resource could not be marshalled.
 
 	ErrUnmarshallingKubernetesResource: `
 A Kubernetes resource could not be unmarshalled.
-`,
-
-	ErrGettingSupportedIngressVersions: `
-The Ingress API versions supported by the k8s API server could not be obtained.
 `,
 
 	//
@@ -728,7 +720,7 @@ The proxy was not allowed to be a part of the mesh.
 `,
 
 	ErrGRPCStreamClosedByProxy: `
-The gRPC stream was closed by the proxy and no DiscoveryRequests can be received. 
+The gRPC stream was closed by the proxy and no DiscoveryRequests can be received.
 The Stream Agreggated Resource server was terminated for the specified proxy.
 `,
 
@@ -809,7 +801,7 @@ The corresponding certificate resource was ignored by the system.
 `,
 
 	ErrGettingServiceCertSecret: `
-An XDS secret containing a TLS certificate could not be retrieved. 
+An XDS secret containing a TLS certificate could not be retrieved.
 The corresponding secret request was ignored by the system.
 `,
 
@@ -835,7 +827,7 @@ A protobuf ProtoMessage could not be converted into YAML.
 `,
 
 	ErrParsingMutatingWebhookCert: `
-The mutating webhook certificate could not be parsed. 
+The mutating webhook certificate could not be parsed.
 The mutating webhook HTTP server was not started.
 `,
 
@@ -852,8 +844,8 @@ The timeout from an AdmissionRequest could not be parsed.
 `,
 
 	ErrInvalidAdmissionReqHeader: `
-The AdmissionRequest's header was invalid. The content type obtained from the 
-header is not supported. 
+The AdmissionRequest's header was invalid. The content type obtained from the
+header is not supported.
 `,
 
 	ErrWritingAdmissionResp: `
@@ -907,7 +899,7 @@ The ValidatingWebhookConfiguration could not be patched with the CA Bundle.
 `,
 
 	ErrParsingValidatingWebhookCert: `
-The validating webhook certificate could not be parsed. 
+The validating webhook certificate could not be parsed.
 The validating webhook HTTP server was not started.
 `,
 }

pkg/ingress/client.go

@@ -30,14 +30,6 @@ var candidateVersions = []string{networkingV1.SchemeGroupVersion.String(), netwo
 
 // NewIngressClient implements ingress.Monitor and creates the Kubernetes client to monitor Ingress resources.
 func NewIngressClient(kubeClient kubernetes.Interface, kubeController k8s.Controller, stop chan struct{}, cfg configurator.Configurator, certProvider certificate.Manager) (Monitor, error) {
-	supportedIngressVersions, err := getSupportedIngressVersions(kubeClient.Discovery())
-	if err != nil {
-		// TODO(#3962): metric might not be scraped before process restart resulting from this error
-		log.Error().Err(err).Str(errcode.Kind, errcode.GetErrCodeWithMetric(errcode.ErrGettingSupportedIngressVersions)).
-			Msgf("Error retrieving ingress API versions supported by k8s API server")
-		return nil, err
-	}
-
 	// Ignore ingresses that have the ignore label
 	ignoreLabel, _ := labels.NewRequirement(constants.IgnoreLabel, selection.DoesNotExist, nil)
 	option := informers.WithTweakListOptions(func(opt *metav1.ListOptions) {
@@ -67,6 +59,8 @@ func NewIngressClient(kubeClient kubernetes.Interface, kubeController k8s.Contro
 		certProvider:   certProvider,
 	}
 
+	supportedIngressVersions := getSupportedIngressVersions(kubeClient.Discovery())
+
 	if v1Supported, ok := supportedIngressVersions[networkingV1.SchemeGroupVersion.String()]; ok && v1Supported {
 		c.informerV1 = informerFactory.Networking().V1().Ingresses().Informer()
 		c.cacheV1 = c.informerV1.GetStore()
@@ -215,14 +209,12 @@ func (c client) GetIngressNetworkingV1(meshService service.MeshService) ([]*netw
 }
 
 // getSupportedIngressVersions returns a map comprising of keys matching candidate ingress API versions
-// and corresponding values indidicating if they are supported by the k8s API server or not. An error
-// is returned in case this cannot be determined.
+// and corresponding values indidicating if they are supported by the k8s API server or not.
 // Example return values:
-// - only networking.k8s.io/v1 is supported: {'networking.k8s.io/v1': true, 'networking.k8s.io/v1beta1': false}, nil
-// - only networking.k8s.io/v1beta1 is supported: {'networking.k8s.io/v1': false, 'networking.k8s.io/v1beta1': true}, nil
-// - both networking.k8s.io/v1 and networking.k8s.io/v1beta1 are supported: {'networking.k8s.io/v1': true, 'networking.k8s.io/v1beta1': true}, nil
-// - on error: nil, error
-func getSupportedIngressVersions(client discovery.ServerResourcesInterface) (map[string]bool, error) {
+// - only networking.k8s.io/v1 is supported: {'networking.k8s.io/v1': true, 'networking.k8s.io/v1beta1': false}
+// - only networking.k8s.io/v1beta1 is supported: {'networking.k8s.io/v1': false, 'networking.k8s.io/v1beta1': true}
+// - both networking.k8s.io/v1 and networking.k8s.io/v1beta1 are supported: {'networking.k8s.io/v1': true, 'networking.k8s.io/v1beta1': true}
+func getSupportedIngressVersions(client discovery.ServerResourcesInterface) map[string]bool {
 	versions := make(map[string]bool)
 
 	for _, groupVersion := range candidateVersions {
@@ -231,7 +223,8 @@ func getSupportedIngressVersions(client discovery.ServerResourcesInterface) (map
 
 		list, err := client.ServerResourcesForGroupVersion(groupVersion)
 		if err != nil {
-			return nil, err
+			// The 'groupVersion' is not supported by the API server
+			continue
 		}
 
 		for _, elem := range list.APIResources {
@@ -242,5 +235,5 @@ func getSupportedIngressVersions(client discovery.ServerResourcesInterface) (map
 		}
 	}
 
-	return versions, nil
+	return versions
 }

pkg/ingress/client_test.go

@@ -31,7 +31,6 @@ func TestGetSupportedIngressVersions(t *testing.T) {
 		name             string
 		discoveryClient  discovery.ServerResourcesInterface
 		expectedVersions map[string]bool
-		exepectError     bool
 	}
 
 	testCases := []testCase{
@@ -53,7 +52,6 @@ func TestGetSupportedIngressVersions(t *testing.T) {
 				"networking.k8s.io/v1":      true,
 				"networking.k8s.io/v1beta1": true,
 			},
-			exepectError: false,
 		},
 		{
 			name: "k8s API server supports only ingress v1beta1",
@@ -72,7 +70,6 @@ func TestGetSupportedIngressVersions(t *testing.T) {
 				"networking.k8s.io/v1":      false,
 				"networking.k8s.io/v1beta1": true,
 			},
-			exepectError: false,
 		},
 		{
 			name: "k8s API server supports only ingress v1",
@@ -91,26 +88,40 @@ func TestGetSupportedIngressVersions(t *testing.T) {
 				"networking.k8s.io/v1":      true,
 				"networking.k8s.io/v1beta1": false,
 			},
-			exepectError: false,
 		},
 		{
 			name: "k8s API server returns an error",
 			discoveryClient: &k8s.FakeDiscoveryClient{
 				Resources: map[string]metav1.APIResourceList{},
 				Err:       errors.New("fake error"),
 			},
-			expectedVersions: nil,
-			exepectError:     true,
+			expectedVersions: map[string]bool{
+				"networking.k8s.io/v1":      false,
+				"networking.k8s.io/v1beta1": false,
+			},
+		},
+		{
+			name: "k8s API server does not support the networking.k8s.io/v1beta1 group version",
+			discoveryClient: &k8s.FakeDiscoveryClient{
+				Resources: map[string]metav1.APIResourceList{
+					"networking.k8s.io/v1beta1": {APIResources: []metav1.APIResource{
+						{Kind: "Ingress"},
+					}},
+				},
+				Err: errors.New("fake"),
+			},
+			expectedVersions: map[string]bool{
+				"networking.k8s.io/v1":      false,
+				"networking.k8s.io/v1beta1": false,
+			},
 		},
 	}
 
 	for i, tc := range testCases {
 		t.Run(fmt.Sprintf("Running test case %d: %s", i, tc.name), func(t *testing.T) {
 			assert := tassert.New(t)
 
-			versions, err := getSupportedIngressVersions(tc.discoveryClient)
-
-			assert.Equal(tc.exepectError, err != nil)
+			versions := getSupportedIngressVersions(tc.discoveryClient)
 			assert.Equal(tc.expectedVersions, versions)
 		})
 	}