expose RunOnce method on RequestHeaderAuthRequest controller

staging/src/k8s.io/apiserver/pkg/authentication/request/headerrequest/requestheader_controller.go

@@ -69,6 +69,7 @@ type RequestHeaderAuthRequestController struct {
 	configmapName      string
 	configmapNamespace string
 
+	client                  kubernetes.Interface
 	configmapLister         corev1listers.ConfigMapNamespaceLister
 	configmapInformer       cache.SharedIndexInformer
 	configmapInformerSynced cache.InformerSynced
@@ -89,10 +90,12 @@ func NewRequestHeaderAuthRequestController(
 	cmName string,
 	cmNamespace string,
 	client kubernetes.Interface,
-	usernameHeadersKey, groupHeadersKey, extraHeaderPrefixesKey, allowedClientNamesKey string) (*RequestHeaderAuthRequestController, error) {
+	usernameHeadersKey, groupHeadersKey, extraHeaderPrefixesKey, allowedClientNamesKey string) *RequestHeaderAuthRequestController {
 	c := &RequestHeaderAuthRequestController{
 		name: "RequestHeaderAuthRequestController",
 
+		client: client,
+
 		configmapName:      cmName,
 		configmapNamespace: cmNamespace,
 
@@ -104,11 +107,6 @@ func NewRequestHeaderAuthRequestController(
 		queue: workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "RequestHeaderAuthRequestController"),
 	}
 
-	// use the live client to prime the controller
-	if err := c.syncOnce(client); err != nil {
-		return nil, err
-	}
-
 	// we construct our own informer because we need such a small subset of the information available.  Just one namespace.
 	c.configmapInformer = coreinformers.NewFilteredConfigMapInformer(client, c.configmapNamespace, 12*time.Hour, cache.Indexers{cache.NamespaceIndex: cache.MetaNamespaceIndexFunc}, func(listOptions *metav1.ListOptions) {
 		listOptions.FieldSelector = fields.OneTermEqualSelector("metadata.name", c.configmapName).String()
@@ -144,7 +142,7 @@ func NewRequestHeaderAuthRequestController(
 	c.configmapLister = corev1listers.NewConfigMapLister(c.configmapInformer.GetIndexer()).ConfigMaps(c.configmapNamespace)
 	c.configmapInformerSynced = c.configmapInformer.HasSynced
 
-	return c, nil
+	return c
 }
 
 func (c *RequestHeaderAuthRequestController) UsernameHeaders() []string {
@@ -184,6 +182,24 @@ func (c *RequestHeaderAuthRequestController) Run(workers int, stopCh <-chan stru
 	<-stopCh
 }
 
+// // RunOnce runs a single sync loop
+func (c *RequestHeaderAuthRequestController) RunOnce() error {
+	configMap, err := c.client.CoreV1().ConfigMaps(c.configmapNamespace).Get(context.TODO(), c.configmapName, metav1.GetOptions{})
+	switch {
+	case errors.IsNotFound(err):
+		// ignore, authConfigMap is nil now
+		return nil
+	case errors.IsForbidden(err):
+		klog.Warningf("Unable to get configmap/%s in %s.  Usually fixed by "+
+			"'kubectl create rolebinding -n %s ROLEBINDING_NAME --role=%s --serviceaccount=YOUR_NS:YOUR_SA'",
+			c.configmapName, c.configmapNamespace, c.configmapNamespace, authenticationRoleName)
+		return err
+	case err != nil:
+		return err
+	}
+	return c.syncConfigMap(configMap)
+}
+
 func (c *RequestHeaderAuthRequestController) runWorker() {
 	for c.processNextWorkItem() {
 	}
@@ -208,23 +224,6 @@ func (c *RequestHeaderAuthRequestController) processNextWorkItem() bool {
 	return true
 }
 
-func (c *RequestHeaderAuthRequestController) syncOnce(client kubernetes.Interface) error {
-	configMap, err := client.CoreV1().ConfigMaps(c.configmapNamespace).Get(context.TODO(), c.configmapName, metav1.GetOptions{})
-	switch {
-	case errors.IsNotFound(err):
-		// ignore, authConfigMap is nil now
-		return nil
-	case errors.IsForbidden(err):
-		klog.Warningf("Unable to get configmap/%s in %s.  Usually fixed by "+
-			"'kubectl create rolebinding -n %s ROLEBINDING_NAME --role=%s --serviceaccount=YOUR_NS:YOUR_SA'",
-			c.configmapName, c.configmapNamespace, c.configmapNamespace, authenticationRoleName)
-		return err
-	case err != nil:
-		return err
-	}
-	return c.syncConfigMap(configMap)
-}
-
 // sync reads the config and propagates the changes to exportedRequestHeaderBundle
 // which is exposed by the set of methods that are used to fill RequestHeaderConfig struct
 func (c *RequestHeaderAuthRequestController) sync() error {

staging/src/k8s.io/apiserver/pkg/authentication/request/headerrequest/requestheader_controller_test.go

@@ -218,9 +218,10 @@ func TestRequestHeaderAuthRequestControllerSyncOnce(t *testing.T) {
 			// test data
 			target := newDefaultTarget()
 			fakeKubeClient := fake.NewSimpleClientset(scenario.cm)
+			target.client = fakeKubeClient
 
 			// act
-			err := target.syncOnce(fakeKubeClient)
+			err := target.RunOnce()
 
 			if err != nil && !scenario.expectErr {
 				t.Errorf("got unexpected error %v", err)

staging/src/k8s.io/apiserver/pkg/server/options/authentication.go

@@ -335,6 +335,11 @@ func (s *DelegatingAuthenticationOptions) createRequestHeaderConfig(client kuber
 		return nil, fmt.Errorf("unable to create request header authentication config: %v", err)
 	}
 
+	//  look up authentication configuration in the cluster and in case of an err defer to authentication-tolerate-lookup-failure flag
+	if err := dynamicRequestHeaderProvider.RunOnce(); err != nil {
+		return nil, err
+	}
+
 	return &authenticatorfactory.RequestHeaderConfig{
 		CAContentProvider:   dynamicRequestHeaderProvider,
 		UsernameHeaders:     headerrequest.StringSliceProvider(headerrequest.StringSliceProviderFunc(dynamicRequestHeaderProvider.UsernameHeaders)),

staging/src/k8s.io/apiserver/pkg/server/options/authentication_dynamic_request_header.go

@@ -1,8 +1,25 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
 package options
 
 import (
 	"fmt"
 
+	"k8s.io/apimachinery/pkg/util/errors"
 	"k8s.io/apiserver/pkg/authentication/request/headerrequest"
 	"k8s.io/apiserver/pkg/server/dynamiccertificates"
 	"k8s.io/client-go/kubernetes"
@@ -33,7 +50,7 @@ func newDynamicRequestHeaderController(client kubernetes.Interface) (*DynamicReq
 		return nil, fmt.Errorf("unable to create DynamicCAFromConfigMap controller: %v", err)
 	}
 
-	requestHeaderAuthRequestController, err := headerrequest.NewRequestHeaderAuthRequestController(
+	requestHeaderAuthRequestController := headerrequest.NewRequestHeaderAuthRequestController(
 		authenticationConfigMapName,
 		authenticationConfigMapNamespace,
 		client,
@@ -42,9 +59,6 @@ func newDynamicRequestHeaderController(client kubernetes.Interface) (*DynamicReq
 		"requestheader-extra-headers-prefix",
 		"requestheader-allowed-names",
 	)
-	if err != nil {
-		return nil, fmt.Errorf("unable to create RequestHeaderAuthRequest controller: %v", err)
-	}
 	return &DynamicRequestHeaderController{
 		ConfigMapCAController:              requestHeaderCAController,
 		RequestHeaderAuthRequestController: requestHeaderAuthRequestController,
@@ -52,7 +66,10 @@ func newDynamicRequestHeaderController(client kubernetes.Interface) (*DynamicReq
 }
 
 func (c *DynamicRequestHeaderController) RunOnce() error {
-	return c.ConfigMapCAController.RunOnce()
+	errs := []error{}
+	errs = append(errs, c.ConfigMapCAController.RunOnce())
+	errs = append(errs, c.RequestHeaderAuthRequestController.RunOnce())
+	return errors.NewAggregate(errs)
 }
 
 func (c *DynamicRequestHeaderController) Run(workers int, stopCh <-chan struct{}) {