feat: add crd gen

Signed-off-by: runzexia <runzexia@yunify.com>

vendor/k8s.io/apiserver/pkg/admission/configuration/configuration_manager.go

@@ -0,0 +1,166 @@
+/*
+Copyright 2017 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 configuration
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/wait"
+)
+
+const (
+	defaultInterval             = 1 * time.Second
+	defaultFailureThreshold     = 5
+	defaultBootstrapRetries     = 5
+	defaultBootstrapGraceperiod = 5 * time.Second
+)
+
+var (
+	ErrNotReady = fmt.Errorf("configuration is not ready")
+	ErrDisabled = fmt.Errorf("disabled")
+)
+
+type getFunc func() (runtime.Object, error)
+
+// When running, poller calls `get` every `interval`. If `get` is
+// successful, `Ready()` returns ready and `configuration()` returns the
+// `mergedConfiguration`; if `get` has failed more than `failureThreshold ` times,
+// `Ready()` returns not ready and `configuration()` returns nil configuration.
+// In an HA setup, the poller is consistent only if the `get` is
+// doing consistent read.
+type poller struct {
+	// a function to consistently read the latest configuration
+	get getFunc
+	// consistent read interval
+	// read-only
+	interval time.Duration
+	// if the number of consecutive read failure equals or exceeds the failureThreshold , the
+	// configuration is regarded as not ready.
+	// read-only
+	failureThreshold int
+	// number of consecutive failures so far.
+	failures int
+	// If the poller has passed the bootstrap phase. The poller is considered
+	// bootstrapped either bootstrapGracePeriod after the first call of
+	// configuration(), or when setConfigurationAndReady() is called, whichever
+	// comes first.
+	bootstrapped bool
+	// configuration() retries bootstrapRetries times if poller is not bootstrapped
+	// read-only
+	bootstrapRetries int
+	// Grace period for bootstrapping
+	// read-only
+	bootstrapGracePeriod time.Duration
+	once                 sync.Once
+	// if the configuration is regarded as ready.
+	ready               bool
+	mergedConfiguration runtime.Object
+	lastErr             error
+	// lock must be hold when reading/writing the data fields of poller.
+	lock sync.RWMutex
+}
+
+func newPoller(get getFunc) *poller {
+	p := poller{
+		get:                  get,
+		interval:             defaultInterval,
+		failureThreshold:     defaultFailureThreshold,
+		bootstrapRetries:     defaultBootstrapRetries,
+		bootstrapGracePeriod: defaultBootstrapGraceperiod,
+	}
+	return &p
+}
+
+func (a *poller) lastError(err error) {
+	a.lock.Lock()
+	defer a.lock.Unlock()
+	a.lastErr = err
+}
+
+func (a *poller) notReady() {
+	a.lock.Lock()
+	defer a.lock.Unlock()
+	a.ready = false
+}
+
+func (a *poller) bootstrapping() {
+	// bootstrapGracePeriod is read-only, so no lock is required
+	timer := time.NewTimer(a.bootstrapGracePeriod)
+	go func() {
+		defer timer.Stop()
+		<-timer.C
+		a.lock.Lock()
+		defer a.lock.Unlock()
+		a.bootstrapped = true
+	}()
+}
+
+// If the poller is not bootstrapped yet, the configuration() gets a few chances
+// to retry. This hides transient failures during system startup.
+func (a *poller) configuration() (runtime.Object, error) {
+	a.once.Do(a.bootstrapping)
+	a.lock.RLock()
+	defer a.lock.RUnlock()
+	retries := 1
+	if !a.bootstrapped {
+		retries = a.bootstrapRetries
+	}
+	for count := 0; count < retries; count++ {
+		if count > 0 {
+			a.lock.RUnlock()
+			time.Sleep(a.interval)
+			a.lock.RLock()
+		}
+		if a.ready {
+			return a.mergedConfiguration, nil
+		}
+	}
+	if a.lastErr != nil {
+		return nil, a.lastErr
+	}
+	return nil, ErrNotReady
+}
+
+func (a *poller) setConfigurationAndReady(value runtime.Object) {
+	a.lock.Lock()
+	defer a.lock.Unlock()
+	a.bootstrapped = true
+	a.mergedConfiguration = value
+	a.ready = true
+	a.lastErr = nil
+}
+
+func (a *poller) Run(stopCh <-chan struct{}) {
+	go wait.Until(a.sync, a.interval, stopCh)
+}
+
+func (a *poller) sync() {
+	configuration, err := a.get()
+	if err != nil {
+		a.failures++
+		a.lastError(err)
+		if a.failures >= a.failureThreshold {
+			a.notReady()
+		}
+		return
+	}
+	a.failures = 0
+	a.setConfigurationAndReady(configuration)
+}