vendor dependencies

vendor/k8s.io/apiserver/plugin/pkg/audit/buffered/buffered.go

@@ -31,16 +31,6 @@ import (
 // PluginName is the name reported in error metrics.
 const PluginName = "buffered"
 
-const (
-	// Default configuration values for ModeBatch.
-	defaultBatchBufferSize = 10000            // Buffer up to 10000 events before starting discarding.
-	defaultBatchMaxSize    = 400              // Only send up to 400 events at a time.
-	defaultBatchMaxWait    = 30 * time.Second // Send events at least twice a minute.
-
-	defaultBatchThrottleQPS   = 10 // Limit the send rate by 10 QPS.
-	defaultBatchThrottleBurst = 15 // Allow up to 15 QPS burst.
-)
-
 // BatchConfig represents batching delegate audit backend configuration.
 type BatchConfig struct {
 	// BufferSize defines a size of the buffering queue.
@@ -57,19 +47,9 @@ type BatchConfig struct {
 	// ThrottleBurst defines the maximum number of requests sent to the delegate backend at the same moment in case
 	// the capacity defined by ThrottleQPS was not utilized.
 	ThrottleBurst int
-}
 
-// NewDefaultBatchConfig returns new Config objects populated by default values.
-func NewDefaultBatchConfig() BatchConfig {
-	return BatchConfig{
-		BufferSize:   defaultBatchBufferSize,
-		MaxBatchSize: defaultBatchMaxSize,
-		MaxBatchWait: defaultBatchMaxWait,
-
-		ThrottleEnable: true,
-		ThrottleQPS:    defaultBatchThrottleQPS,
-		ThrottleBurst:  defaultBatchThrottleBurst,
-	}
+	// Whether the delegate backend should be called asynchronously.
+	AsyncDelegate bool
 }
 
 type bufferedBackend struct {
@@ -85,6 +65,9 @@ type bufferedBackend struct {
 	// Receiving maxBatchSize events will always trigger sending a batch, regardless of the amount of time passed.
 	maxBatchWait time.Duration
 
+	// Whether the delegate backend should be called asynchronously.
+	asyncDelegate bool
+
 	// Channel to signal that the batching routine has processed all remaining events and exited.
 	// Once `shutdownCh` is closed no new events will be sent to the delegate backend.
 	shutdownCh chan struct{}
@@ -113,6 +96,7 @@ func NewBackend(delegate audit.Backend, config BatchConfig) audit.Backend {
 		buffer:          make(chan *auditinternal.Event, config.BufferSize),
 		maxBatchSize:    config.MaxBatchSize,
 		maxBatchWait:    config.MaxBatchWait,
+		asyncDelegate:   config.AsyncDelegate,
 		shutdownCh:      make(chan struct{}),
 		wg:              sync.WaitGroup{},
 		throttle:        throttle,
@@ -169,8 +153,17 @@ func (b *bufferedBackend) Shutdown() {
 // b.stopCh is closed, processIncomingEvents stops and closes the buffer.
 func (b *bufferedBackend) processIncomingEvents(stopCh <-chan struct{}) {
 	defer close(b.buffer)
-	t := time.NewTimer(b.maxBatchWait)
-	defer t.Stop()
+
+	var (
+		maxWaitChan  <-chan time.Time
+		maxWaitTimer *time.Timer
+	)
+	// Only use max wait batching if batching is enabled.
+	if b.maxBatchSize > 1 {
+		maxWaitTimer = time.NewTimer(b.maxBatchWait)
+		maxWaitChan = maxWaitTimer.C
+		defer maxWaitTimer.Stop()
+	}
 
 	for {
 		func() {
@@ -178,8 +171,10 @@ func (b *bufferedBackend) processIncomingEvents(stopCh <-chan struct{}) {
 			// goroutine can't bring down the main routine.
 			defer runtime.HandleCrash()
 
-			t.Reset(b.maxBatchWait)
-			b.processEvents(b.collectEvents(t.C, stopCh))
+			if b.maxBatchSize > 1 {
+				maxWaitTimer.Reset(b.maxBatchWait)
+			}
+			b.processEvents(b.collectEvents(maxWaitChan, stopCh))
 		}()
 
 		select {
@@ -235,18 +230,28 @@ func (b *bufferedBackend) processEvents(events []*auditinternal.Event) {
 		b.throttle.Accept()
 	}
 
-	b.wg.Add(1)
-	go func() {
-		defer b.wg.Done()
-		defer runtime.HandleCrash()
+	if b.asyncDelegate {
+		b.wg.Add(1)
+		go func() {
+			defer b.wg.Done()
+			defer runtime.HandleCrash()
 
-		// Execute the real processing in a goroutine to keep it from blocking.
-		// This lets the batching routine continue draining the queue immediately.
-		b.delegateBackend.ProcessEvents(events...)
-	}()
+			// Execute the real processing in a goroutine to keep it from blocking.
+			// This lets the batching routine continue draining the queue immediately.
+			b.delegateBackend.ProcessEvents(events...)
+		}()
+	} else {
+		func() {
+			defer runtime.HandleCrash()
+
+			// Execute the real processing in a goroutine to keep it from blocking.
+			// This lets the batching routine continue draining the queue immediately.
+			b.delegateBackend.ProcessEvents(events...)
+		}()
+	}
 }
 
-func (b *bufferedBackend) ProcessEvents(ev ...*auditinternal.Event) {
+func (b *bufferedBackend) ProcessEvents(ev ...*auditinternal.Event) bool {
 	// The following mechanism is in place to support the situation when audit
 	// events are still coming after the backend was stopped.
 	var sendErr error
@@ -274,9 +279,10 @@ func (b *bufferedBackend) ProcessEvents(ev ...*auditinternal.Event) {
 		case b.buffer <- event:
 		default:
 			sendErr = fmt.Errorf("audit buffer queue blocked")
-			return
+			return true
 		}
 	}
+	return true
 }
 
 func (b *bufferedBackend) String() string {

vendor/k8s.io/apiserver/plugin/pkg/audit/dynamic/defaults.go

@@ -0,0 +1,46 @@
+/*
+Copyright 2018 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 dynamic
+
+import (
+	"time"
+
+	bufferedplugin "k8s.io/apiserver/plugin/pkg/audit/buffered"
+)
+
+const (
+	// Default configuration values for ModeBatch when applied to a dynamic plugin
+	defaultBatchBufferSize    = 5000             // Buffer up to 5000 events before starting discarding.
+	defaultBatchMaxSize       = 400              // Only send up to 400 events at a time.
+	defaultBatchMaxWait       = 30 * time.Second // Send events at least twice a minute.
+	defaultBatchThrottleQPS   = 10               // Limit the send rate by 10 QPS.
+	defaultBatchThrottleBurst = 15               // Allow up to 15 QPS burst.
+)
+
+// NewDefaultWebhookBatchConfig returns new Batch Config objects populated by default values
+// for dynamic webhooks
+func NewDefaultWebhookBatchConfig() *bufferedplugin.BatchConfig {
+	return &bufferedplugin.BatchConfig{
+		BufferSize:     defaultBatchBufferSize,
+		MaxBatchSize:   defaultBatchMaxSize,
+		MaxBatchWait:   defaultBatchMaxWait,
+		ThrottleEnable: true,
+		ThrottleQPS:    defaultBatchThrottleQPS,
+		ThrottleBurst:  defaultBatchThrottleBurst,
+		AsyncDelegate:  true,
+	}
+}

vendor/k8s.io/apiserver/plugin/pkg/audit/dynamic/dynamic.go

@@ -0,0 +1,342 @@
+/*
+Copyright 2018 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 dynamic
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"sync"
+	"sync/atomic"
+
+	"k8s.io/klog"
+
+	auditregv1alpha1 "k8s.io/api/auditregistration/v1alpha1"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
+	auditinternal "k8s.io/apiserver/pkg/apis/audit"
+	auditinstall "k8s.io/apiserver/pkg/apis/audit/install"
+	auditv1 "k8s.io/apiserver/pkg/apis/audit/v1"
+	"k8s.io/apiserver/pkg/audit"
+	webhook "k8s.io/apiserver/pkg/util/webhook"
+	bufferedplugin "k8s.io/apiserver/plugin/pkg/audit/buffered"
+	auditinformer "k8s.io/client-go/informers/auditregistration/v1alpha1"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/tools/record"
+)
+
+// PluginName is the name reported in error metrics.
+const PluginName = "dynamic"
+
+// Config holds the configuration for the dynamic backend
+type Config struct {
+	// Informer for the audit sinks
+	Informer auditinformer.AuditSinkInformer
+	// EventConfig holds the configuration for event notifications about the AuditSink API objects
+	EventConfig EventConfig
+	// BufferedConfig is the runtime buffered configuration
+	BufferedConfig *bufferedplugin.BatchConfig
+	// WebhookConfig holds the configuration for outgoing webhooks
+	WebhookConfig WebhookConfig
+}
+
+// WebhookConfig holds the configurations for outgoing webhooks
+type WebhookConfig struct {
+	// AuthInfoResolverWrapper provides the webhook authentication for in-cluster endpoints
+	AuthInfoResolverWrapper webhook.AuthenticationInfoResolverWrapper
+	// ServiceResolver knows how to convert a webhook service reference into an actual location.
+	ServiceResolver webhook.ServiceResolver
+}
+
+// EventConfig holds the configurations for sending event notifiations about AuditSink API objects
+type EventConfig struct {
+	// Sink for emitting events
+	Sink record.EventSink
+	// Source holds the source information about the event emitter
+	Source corev1.EventSource
+}
+
+// delegate represents a delegate backend that was created from an audit sink configuration
+type delegate struct {
+	audit.Backend
+	configuration *auditregv1alpha1.AuditSink
+	stopChan      chan struct{}
+}
+
+// gracefulShutdown will gracefully shutdown the delegate
+func (d *delegate) gracefulShutdown() {
+	close(d.stopChan)
+	d.Shutdown()
+}
+
+// NewBackend returns a backend that dynamically updates its configuration
+// based on a shared informer.
+func NewBackend(c *Config) (audit.Backend, error) {
+	eventBroadcaster := record.NewBroadcaster()
+	eventBroadcaster.StartLogging(klog.Infof)
+	eventBroadcaster.StartRecordingToSink(c.EventConfig.Sink)
+
+	scheme := runtime.NewScheme()
+	err := auditregv1alpha1.AddToScheme(scheme)
+	if err != nil {
+		return nil, err
+	}
+	recorder := eventBroadcaster.NewRecorder(scheme, c.EventConfig.Source)
+
+	if c.BufferedConfig == nil {
+		c.BufferedConfig = NewDefaultWebhookBatchConfig()
+	}
+	cm, err := webhook.NewClientManager(auditv1.SchemeGroupVersion, func(s *runtime.Scheme) error {
+		auditinstall.Install(s)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO: need a way of injecting authentication before beta
+	authInfoResolver, err := webhook.NewDefaultAuthenticationInfoResolver("")
+	if err != nil {
+		return nil, err
+	}
+	cm.SetAuthenticationInfoResolver(authInfoResolver)
+	cm.SetServiceResolver(c.WebhookConfig.ServiceResolver)
+	cm.SetAuthenticationInfoResolverWrapper(c.WebhookConfig.AuthInfoResolverWrapper)
+
+	manager := &backend{
+		config:               c,
+		delegates:            atomic.Value{},
+		delegateUpdateMutex:  sync.Mutex{},
+		webhookClientManager: cm,
+		recorder:             recorder,
+	}
+	manager.delegates.Store(syncedDelegates{})
+
+	c.Informer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc: func(obj interface{}) {
+			manager.addSink(obj.(*auditregv1alpha1.AuditSink))
+		},
+		UpdateFunc: func(oldObj, newObj interface{}) {
+			manager.updateSink(oldObj.(*auditregv1alpha1.AuditSink), newObj.(*auditregv1alpha1.AuditSink))
+		},
+		DeleteFunc: func(obj interface{}) {
+			sink, ok := obj.(*auditregv1alpha1.AuditSink)
+			if !ok {
+				tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
+				if !ok {
+					klog.V(2).Infof("Couldn't get object from tombstone %#v", obj)
+					return
+				}
+				sink, ok = tombstone.Obj.(*auditregv1alpha1.AuditSink)
+				if !ok {
+					klog.V(2).Infof("Tombstone contained object that is not an AuditSink: %#v", obj)
+					return
+				}
+			}
+			manager.deleteSink(sink)
+		},
+	})
+
+	return manager, nil
+}
+
+type backend struct {
+	// delegateUpdateMutex holds an update lock on the delegates
+	delegateUpdateMutex  sync.Mutex
+	config               *Config
+	delegates            atomic.Value
+	webhookClientManager webhook.ClientManager
+	recorder             record.EventRecorder
+}
+
+type syncedDelegates map[types.UID]*delegate
+
+// Names returns the names of the delegate configurations
+func (s syncedDelegates) Names() []string {
+	names := []string{}
+	for _, delegate := range s {
+		names = append(names, delegate.configuration.Name)
+	}
+	return names
+}
+
+// ProcessEvents proccesses the given events per current delegate map
+func (b *backend) ProcessEvents(events ...*auditinternal.Event) bool {
+	for _, d := range b.GetDelegates() {
+		d.ProcessEvents(events...)
+	}
+	// Returning true regardless of results, since dynamic audit backends
+	// can never cause apiserver request to fail.
+	return true
+}
+
+// Run starts a goroutine that propagates the shutdown signal,
+// individual delegates are ran as they are created.
+func (b *backend) Run(stopCh <-chan struct{}) error {
+	go func() {
+		<-stopCh
+		b.stopAllDelegates()
+	}()
+	return nil
+}
+
+// stopAllDelegates closes the stopChan for every delegate to enable
+// goroutines to terminate gracefully. This is a helper method to propagate
+// the primary stopChan to the current delegate map.
+func (b *backend) stopAllDelegates() {
+	b.delegateUpdateMutex.Lock()
+	for _, d := range b.GetDelegates() {
+		close(d.stopChan)
+	}
+}
+
+// Shutdown calls the shutdown method on all delegates. The stopChan should
+// be closed before this is called.
+func (b *backend) Shutdown() {
+	for _, d := range b.GetDelegates() {
+		d.Shutdown()
+	}
+}
+
+// GetDelegates retrieves current delegates in a safe manner
+func (b *backend) GetDelegates() syncedDelegates {
+	return b.delegates.Load().(syncedDelegates)
+}
+
+// copyDelegates returns a copied delegate map
+func (b *backend) copyDelegates() syncedDelegates {
+	c := make(syncedDelegates)
+	for u, s := range b.GetDelegates() {
+		c[u] = s
+	}
+	return c
+}
+
+// setDelegates sets the current delegates in a safe manner
+func (b *backend) setDelegates(delegates syncedDelegates) {
+	b.delegates.Store(delegates)
+}
+
+// addSink is called by the shared informer when a sink is added
+func (b *backend) addSink(sink *auditregv1alpha1.AuditSink) {
+	b.delegateUpdateMutex.Lock()
+	defer b.delegateUpdateMutex.Unlock()
+	delegates := b.copyDelegates()
+	if _, ok := delegates[sink.UID]; ok {
+		klog.Errorf("Audit sink %q uid: %s already exists, could not readd", sink.Name, sink.UID)
+		return
+	}
+	d, err := b.createAndStartDelegate(sink)
+	if err != nil {
+		msg := fmt.Sprintf("Could not add audit sink %q: %v", sink.Name, err)
+		klog.Error(msg)
+		b.recorder.Event(sink, corev1.EventTypeWarning, "CreateFailed", msg)
+		return
+	}
+	delegates[sink.UID] = d
+	b.setDelegates(delegates)
+	klog.V(2).Infof("Added audit sink: %s", sink.Name)
+	klog.V(2).Infof("Current audit sinks: %v", delegates.Names())
+}
+
+// updateSink is called by the shared informer when a sink is updated.
+// The new sink is only rebuilt on spec changes. The new sink must not have
+// the same uid as the previous. The new sink will be started before the old
+// one is shutdown so no events will be lost
+func (b *backend) updateSink(oldSink, newSink *auditregv1alpha1.AuditSink) {
+	b.delegateUpdateMutex.Lock()
+	defer b.delegateUpdateMutex.Unlock()
+	delegates := b.copyDelegates()
+	oldDelegate, ok := delegates[oldSink.UID]
+	if !ok {
+		klog.Errorf("Could not update audit sink %q uid: %s, old sink does not exist",
+			oldSink.Name, oldSink.UID)
+		return
+	}
+
+	// check if spec has changed
+	eq := reflect.DeepEqual(oldSink.Spec, newSink.Spec)
+	if eq {
+		delete(delegates, oldSink.UID)
+		delegates[newSink.UID] = oldDelegate
+		b.setDelegates(delegates)
+	} else {
+		d, err := b.createAndStartDelegate(newSink)
+		if err != nil {
+			msg := fmt.Sprintf("Could not update audit sink %q: %v", oldSink.Name, err)
+			klog.Error(msg)
+			b.recorder.Event(newSink, corev1.EventTypeWarning, "UpdateFailed", msg)
+			return
+		}
+		delete(delegates, oldSink.UID)
+		delegates[newSink.UID] = d
+		b.setDelegates(delegates)
+
+		// graceful shutdown in goroutine as to not block
+		go oldDelegate.gracefulShutdown()
+	}
+
+	klog.V(2).Infof("Updated audit sink: %s", newSink.Name)
+	klog.V(2).Infof("Current audit sinks: %v", delegates.Names())
+}
+
+// deleteSink is called by the shared informer when a sink is deleted
+func (b *backend) deleteSink(sink *auditregv1alpha1.AuditSink) {
+	b.delegateUpdateMutex.Lock()
+	defer b.delegateUpdateMutex.Unlock()
+	delegates := b.copyDelegates()
+	delegate, ok := delegates[sink.UID]
+	if !ok {
+		klog.Errorf("Could not delete audit sink %q uid: %s, does not exist", sink.Name, sink.UID)
+		return
+	}
+	delete(delegates, sink.UID)
+	b.setDelegates(delegates)
+
+	// graceful shutdown in goroutine as to not block
+	go delegate.gracefulShutdown()
+	klog.V(2).Infof("Deleted audit sink: %s", sink.Name)
+	klog.V(2).Infof("Current audit sinks: %v", delegates.Names())
+}
+
+// createAndStartDelegate will build a delegate from an audit sink configuration and run it
+func (b *backend) createAndStartDelegate(sink *auditregv1alpha1.AuditSink) (*delegate, error) {
+	f := factory{
+		config:               b.config,
+		webhookClientManager: b.webhookClientManager,
+		sink:                 sink,
+	}
+	delegate, err := f.BuildDelegate()
+	if err != nil {
+		return nil, err
+	}
+	err = delegate.Run(delegate.stopChan)
+	if err != nil {
+		return nil, err
+	}
+	return delegate, nil
+}
+
+// String returns a string representation of the backend
+func (b *backend) String() string {
+	var delegateStrings []string
+	for _, delegate := range b.GetDelegates() {
+		delegateStrings = append(delegateStrings, fmt.Sprintf("%s", delegate))
+	}
+	return fmt.Sprintf("%s[%s]", PluginName, strings.Join(delegateStrings, ","))
+}

vendor/k8s.io/apiserver/plugin/pkg/audit/dynamic/enforced/enforced.go

@@ -0,0 +1,93 @@
+/*
+Copyright 2018 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 enforced
+
+import (
+	"fmt"
+
+	auditinternal "k8s.io/apiserver/pkg/apis/audit"
+	"k8s.io/apiserver/pkg/audit"
+	ev "k8s.io/apiserver/pkg/audit/event"
+	"k8s.io/apiserver/pkg/audit/policy"
+)
+
+// PluginName is the name reported in error metrics.
+const PluginName = "enforced"
+
+// Backend filters audit events according to the policy
+// trimming them as necessary to match the level
+type Backend struct {
+	policyChecker   policy.Checker
+	delegateBackend audit.Backend
+}
+
+// NewBackend returns an enforced audit backend that wraps delegate backend.
+// Enforced backend automatically runs and shuts down the delegate backend.
+func NewBackend(delegate audit.Backend, p policy.Checker) audit.Backend {
+	return &Backend{
+		policyChecker:   p,
+		delegateBackend: delegate,
+	}
+}
+
+// Run the delegate backend
+func (b Backend) Run(stopCh <-chan struct{}) error {
+	return b.delegateBackend.Run(stopCh)
+}
+
+// Shutdown the delegate backend
+func (b Backend) Shutdown() {
+	b.delegateBackend.Shutdown()
+}
+
+// ProcessEvents enforces policy on a shallow copy of the given event
+// dropping any sections that don't conform
+func (b Backend) ProcessEvents(events ...*auditinternal.Event) bool {
+	for _, event := range events {
+		if event == nil {
+			continue
+		}
+		attr, err := ev.NewAttributes(event)
+		if err != nil {
+			audit.HandlePluginError(PluginName, err, event)
+			continue
+		}
+		level, stages := b.policyChecker.LevelAndStages(attr)
+		if level == auditinternal.LevelNone {
+			continue
+		}
+		// make shallow copy before modifying to satisfy interface definition
+		ev := *event
+		e, err := policy.EnforcePolicy(&ev, level, stages)
+		if err != nil {
+			audit.HandlePluginError(PluginName, err, event)
+			continue
+		}
+		if e == nil {
+			continue
+		}
+		b.delegateBackend.ProcessEvents(e)
+	}
+	// Returning true regardless of results, since dynamic audit backends
+	// can never cause apiserver request to fail.
+	return true
+}
+
+// String returns a string representation of the backend
+func (b Backend) String() string {
+	return fmt.Sprintf("%s<%s>", PluginName, b.delegateBackend)
+}

vendor/k8s.io/apiserver/plugin/pkg/audit/dynamic/factory.go

@@ -0,0 +1,91 @@
+/*
+Copyright 2018 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 dynamic
+
+import (
+	"fmt"
+	"time"
+
+	auditregv1alpha1 "k8s.io/api/auditregistration/v1alpha1"
+	"k8s.io/apiserver/pkg/audit"
+	"k8s.io/apiserver/pkg/audit/policy"
+	auditutil "k8s.io/apiserver/pkg/audit/util"
+	"k8s.io/apiserver/pkg/util/webhook"
+	bufferedplugin "k8s.io/apiserver/plugin/pkg/audit/buffered"
+	enforcedplugin "k8s.io/apiserver/plugin/pkg/audit/dynamic/enforced"
+	webhookplugin "k8s.io/apiserver/plugin/pkg/audit/webhook"
+)
+
+// TODO: find a common place for all the default retry backoffs
+const retryBackoff = 500 * time.Millisecond
+
+// factory builds a delegate from an AuditSink
+type factory struct {
+	config               *Config
+	webhookClientManager webhook.ClientManager
+	sink                 *auditregv1alpha1.AuditSink
+}
+
+// BuildDelegate creates a delegate from the AuditSink object
+func (f *factory) BuildDelegate() (*delegate, error) {
+	backend, err := f.buildWebhookBackend()
+	if err != nil {
+		return nil, err
+	}
+	backend = f.applyEnforcedOpts(backend)
+	backend = f.applyBufferedOpts(backend)
+	ch := make(chan struct{})
+	return &delegate{
+		Backend:       backend,
+		configuration: f.sink,
+		stopChan:      ch,
+	}, nil
+}
+
+func (f *factory) buildWebhookBackend() (audit.Backend, error) {
+	hookClient := auditutil.HookClientConfigForSink(f.sink)
+	client, err := f.webhookClientManager.HookClient(hookClient)
+	if err != nil {
+		return nil, fmt.Errorf("could not create webhook client: %v", err)
+	}
+	backend := webhookplugin.NewDynamicBackend(client, retryBackoff)
+	return backend, nil
+}
+
+func (f *factory) applyEnforcedOpts(delegate audit.Backend) audit.Backend {
+	pol := policy.ConvertDynamicPolicyToInternal(&f.sink.Spec.Policy)
+	checker := policy.NewChecker(pol)
+	eb := enforcedplugin.NewBackend(delegate, checker)
+	return eb
+}
+
+func (f *factory) applyBufferedOpts(delegate audit.Backend) audit.Backend {
+	bc := f.config.BufferedConfig
+	tc := f.sink.Spec.Webhook.Throttle
+	if tc != nil {
+		bc.ThrottleEnable = true
+		if tc.Burst != nil {
+			bc.ThrottleBurst = int(*tc.Burst)
+		}
+		if tc.QPS != nil {
+			bc.ThrottleQPS = float32(*tc.QPS)
+		}
+	} else {
+		bc.ThrottleEnable = false
+	}
+	return bufferedplugin.NewBackend(delegate, *bc)
+}

vendor/k8s.io/apiserver/plugin/pkg/audit/log/backend.go

@@ -59,13 +59,15 @@ func NewBackend(out io.Writer, format string, groupVersion schema.GroupVersion)
 	}
 }
 
-func (b *backend) ProcessEvents(events ...*auditinternal.Event) {
+func (b *backend) ProcessEvents(events ...*auditinternal.Event) bool {
+	success := true
 	for _, ev := range events {
-		b.logEvent(ev)
+		success = b.logEvent(ev) && success
 	}
+	return success
 }
 
-func (b *backend) logEvent(ev *auditinternal.Event) {
+func (b *backend) logEvent(ev *auditinternal.Event) bool {
 	line := ""
 	switch b.format {
 	case FormatLegacy:
@@ -74,17 +76,19 @@ func (b *backend) logEvent(ev *auditinternal.Event) {
 		bs, err := runtime.Encode(audit.Codecs.LegacyCodec(b.groupVersion), ev)
 		if err != nil {
 			audit.HandlePluginError(PluginName, err, ev)
-			return
+			return false
 		}
 		line = string(bs[:])
 	default:
 		audit.HandlePluginError(PluginName, fmt.Errorf("log format %q is not in list of known formats (%s)",
 			b.format, strings.Join(AllowedFormats, ",")), ev)
-		return
+		return false
 	}
 	if _, err := fmt.Fprint(b.out, line); err != nil {
 		audit.HandlePluginError(PluginName, err, ev)
+		return false
 	}
+	return true
 }
 
 func (b *backend) Run(stopCh <-chan struct{}) error {

vendor/k8s.io/apiserver/plugin/pkg/audit/truncate/truncate.go

@@ -71,11 +71,12 @@ func NewBackend(delegateBackend audit.Backend, config Config, groupVersion schem
 	}
 }
 
-func (b *backend) ProcessEvents(events ...*auditinternal.Event) {
+func (b *backend) ProcessEvents(events ...*auditinternal.Event) bool {
 	var errors []error
 	var impacted []*auditinternal.Event
 	var batch []*auditinternal.Event
 	var batchSize int64
+	success := true
 	for _, event := range events {
 		size, err := b.calcSize(event)
 		// If event was correctly serialized, but the size is more than allowed
@@ -97,7 +98,7 @@ func (b *backend) ProcessEvents(events ...*auditinternal.Event) {
 		}
 
 		if len(batch) > 0 && batchSize+size > b.c.MaxBatchSize {
-			b.delegateBackend.ProcessEvents(batch...)
+			success = b.delegateBackend.ProcessEvents(batch...) && success
 			batch = []*auditinternal.Event{}
 			batchSize = 0
 		}
@@ -107,12 +108,13 @@ func (b *backend) ProcessEvents(events ...*auditinternal.Event) {
 	}
 
 	if len(batch) > 0 {
-		b.delegateBackend.ProcessEvents(batch...)
+		success = b.delegateBackend.ProcessEvents(batch...) && success
 	}
 
 	if len(impacted) > 0 {
 		audit.HandlePluginError(PluginName, utilerrors.NewAggregate(errors), impacted...)
 	}
+	return success
 }
 
 // truncate removed request and response objects from the audit events,

vendor/k8s.io/apiserver/plugin/pkg/audit/webhook/webhook.go

@@ -18,6 +18,7 @@ limitations under the License.
 package webhook
 
 import (
+	"fmt"
 	"time"
 
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -47,7 +48,20 @@ func loadWebhook(configFile string, groupVersion schema.GroupVersion, initialBac
 }
 
 type backend struct {
-	w *webhook.GenericWebhook
+	w    *webhook.GenericWebhook
+	name string
+}
+
+// NewDynamicBackend returns an audit backend configured from a REST client that
+// sends events over HTTP to an external service.
+func NewDynamicBackend(rc *rest.RESTClient, initialBackoff time.Duration) audit.Backend {
+	return &backend{
+		w: &webhook.GenericWebhook{
+			RestClient:     rc,
+			InitialBackoff: initialBackoff,
+		},
+		name: fmt.Sprintf("dynamic_%s", PluginName),
+	}
 }
 
 // NewBackend returns an audit backend that sends events over HTTP to an external service.
@@ -56,7 +70,7 @@ func NewBackend(kubeConfigFile string, groupVersion schema.GroupVersion, initial
 	if err != nil {
 		return nil, err
 	}
-	return &backend{w}, nil
+	return &backend{w: w, name: PluginName}, nil
 }
 
 func (b *backend) Run(stopCh <-chan struct{}) error {
@@ -67,10 +81,12 @@ func (b *backend) Shutdown() {
 	// nothing to do here
 }
 
-func (b *backend) ProcessEvents(ev ...*auditinternal.Event) {
+func (b *backend) ProcessEvents(ev ...*auditinternal.Event) bool {
 	if err := b.processEvents(ev...); err != nil {
-		audit.HandlePluginError(PluginName, err, ev...)
+		audit.HandlePluginError(b.String(), err, ev...)
+		return false
 	}
+	return true
 }
 
 func (b *backend) processEvents(ev ...*auditinternal.Event) error {
@@ -84,5 +100,5 @@ func (b *backend) processEvents(ev ...*auditinternal.Event) error {
 }
 
 func (b *backend) String() string {
-	return PluginName
+	return b.name
 }