istio

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/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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    http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package k8sresourcelock
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import (
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	"context"
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	"encoding/json"
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	"errors"
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	"fmt"
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	v1 "k8s.io/api/core/v1"
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	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
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)
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type EndpointsLock struct {
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	// EndpointsMeta should contain a Name and a Namespace of an
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	// Endpoints object that the LeaderElector will attempt to lead.
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	EndpointsMeta metav1.ObjectMeta
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	Client        corev1client.EndpointsGetter
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	LockConfig    ResourceLockConfig
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	e             *v1.Endpoints
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}
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// Get returns the election record from a Endpoints Annotation
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func (el *EndpointsLock) Get(ctx context.Context) (*LeaderElectionRecord, []byte, error) {
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	var record LeaderElectionRecord
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	var err error
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	el.e, err = el.Client.Endpoints(el.EndpointsMeta.Namespace).Get(ctx, el.EndpointsMeta.Name, metav1.GetOptions{})
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	if err != nil {
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		return nil, nil, err
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	}
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	if el.e.Annotations == nil {
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		el.e.Annotations = make(map[string]string)
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	}
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	recordStr, found := el.e.Annotations[LeaderElectionRecordAnnotationKey]
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	recordBytes := []byte(recordStr)
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	if found {
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		if err := json.Unmarshal(recordBytes, &record); err != nil {
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			return nil, nil, err
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		}
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	}
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	return &record, recordBytes, nil
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}
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// Create attempts to create a LeaderElectionRecord annotation
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func (el *EndpointsLock) Create(ctx context.Context, ler LeaderElectionRecord) error {
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	recordBytes, err := json.Marshal(ler)
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	if err != nil {
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		return err
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	}
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	el.e, err = el.Client.Endpoints(el.EndpointsMeta.Namespace).Create(ctx, &v1.Endpoints{
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		ObjectMeta: metav1.ObjectMeta{
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			Name:      el.EndpointsMeta.Name,
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			Namespace: el.EndpointsMeta.Namespace,
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			Annotations: map[string]string{
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				LeaderElectionRecordAnnotationKey: string(recordBytes),
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			},
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		},
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	}, metav1.CreateOptions{})
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	return err
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}
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// Update will update and existing annotation on a given resource.
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func (el *EndpointsLock) Update(ctx context.Context, ler LeaderElectionRecord) error {
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	if el.e == nil {
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		return errors.New("endpoint not initialized, call get or create first")
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	}
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	recordBytes, err := json.Marshal(ler)
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	if err != nil {
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		return err
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	}
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	if el.e.Annotations == nil {
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		el.e.Annotations = make(map[string]string)
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	}
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	el.e.Annotations[LeaderElectionRecordAnnotationKey] = string(recordBytes)
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	e, err := el.Client.Endpoints(el.EndpointsMeta.Namespace).Update(ctx, el.e, metav1.UpdateOptions{})
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	if err != nil {
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		return err
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	}
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	el.e = e
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	return nil
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}
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// RecordEvent in leader election while adding meta-data
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func (el *EndpointsLock) RecordEvent(s string) {
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	if el.LockConfig.EventRecorder == nil {
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		return
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	}
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	events := fmt.Sprintf("%v %v", el.LockConfig.Identity, s)
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	el.LockConfig.EventRecorder.Eventf(&v1.Endpoints{ObjectMeta: el.e.ObjectMeta}, v1.EventTypeNormal, "LeaderElection", events)
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}
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// Describe is used to convert details on current resource lock
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// into a string
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func (el *EndpointsLock) Describe() string {
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	return fmt.Sprintf("%v/%v", el.EndpointsMeta.Namespace, el.EndpointsMeta.Name)
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}
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// Identity returns the Identity of the lock
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func (el *EndpointsLock) Identity() string {
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	return el.LockConfig.Identity
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}
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// Key returns the Key of the lock
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func (el *EndpointsLock) Key() string {
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	return el.LockConfig.Key
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}
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