istio

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/*
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Copyright 2018 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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	coordinationv1 "k8s.io/api/coordination/v1"
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	corev1 "k8s.io/api/core/v1"
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	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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	coordinationv1client "k8s.io/client-go/kubernetes/typed/coordination/v1"
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)
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type LeaseLock struct {
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	// LeaseMeta should contain a Name and a Namespace of a
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	// LeaseMeta object that the LeaderElector will attempt to lead.
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	LeaseMeta  metav1.ObjectMeta
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	Client     coordinationv1client.LeasesGetter
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	LockConfig ResourceLockConfig
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	lease      *coordinationv1.Lease
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}
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// Get returns the election record from a Lease spec
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func (ll *LeaseLock) Get(ctx context.Context) (*LeaderElectionRecord, []byte, error) {
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	var err error
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	ll.lease, err = ll.Client.Leases(ll.LeaseMeta.Namespace).Get(ctx, ll.LeaseMeta.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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	record := LeaseSpecToLeaderElectionRecord(&ll.lease.Spec)
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	recordByte, err := json.Marshal(*record)
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	if err != nil {
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		return nil, nil, err
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	}
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	return record, recordByte, nil
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}
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// Create attempts to create a Lease
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func (ll *LeaseLock) Create(ctx context.Context, ler LeaderElectionRecord) error {
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	var err error
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	ll.lease, err = ll.Client.Leases(ll.LeaseMeta.Namespace).Create(ctx, &coordinationv1.Lease{
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		ObjectMeta: metav1.ObjectMeta{
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			Name:      ll.LeaseMeta.Name,
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			Namespace: ll.LeaseMeta.Namespace,
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		},
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		Spec: LeaderElectionRecordToLeaseSpec(&ler),
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	}, metav1.CreateOptions{})
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	return err
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}
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// Update will update an existing Lease spec.
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func (ll *LeaseLock) Update(ctx context.Context, ler LeaderElectionRecord) error {
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	if ll.lease == nil {
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		return errors.New("lease not initialized, call get or create first")
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	}
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	ll.lease.Spec = LeaderElectionRecordToLeaseSpec(&ler)
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	lease, err := ll.Client.Leases(ll.LeaseMeta.Namespace).Update(ctx, ll.lease, metav1.UpdateOptions{})
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	if err != nil {
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		return err
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	}
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	ll.lease = lease
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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 (ll *LeaseLock) RecordEvent(s string) {
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	if ll.LockConfig.EventRecorder == nil {
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		return
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	}
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	events := fmt.Sprintf("%v %v", ll.LockConfig.Identity, s)
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	ll.LockConfig.EventRecorder.Eventf(&coordinationv1.Lease{ObjectMeta: ll.lease.ObjectMeta}, corev1.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 (ll *LeaseLock) Describe() string {
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	return fmt.Sprintf("%v/%v", ll.LeaseMeta.Namespace, ll.LeaseMeta.Name)
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}
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// Identity returns the Identity of the lock
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func (ll *LeaseLock) Identity() string {
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	return ll.LockConfig.Identity
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}
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// Key returns the Key of the lock
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func (ll *LeaseLock) Key() string {
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	return ll.LockConfig.Key
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}
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func LeaseSpecToLeaderElectionRecord(spec *coordinationv1.LeaseSpec) *LeaderElectionRecord {
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	var r LeaderElectionRecord
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	if spec.HolderIdentity != nil {
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		r.HolderIdentity = *spec.HolderIdentity
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	}
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	if spec.LeaseDurationSeconds != nil {
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		r.LeaseDurationSeconds = int(*spec.LeaseDurationSeconds)
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	}
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	if spec.LeaseTransitions != nil {
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		r.LeaderTransitions = int(*spec.LeaseTransitions)
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	}
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	if spec.AcquireTime != nil {
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		r.AcquireTime = metav1.Time{Time: spec.AcquireTime.Time}
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	}
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	if spec.RenewTime != nil {
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		r.RenewTime = metav1.Time{Time: spec.RenewTime.Time}
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	}
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	return &r
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}
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func LeaderElectionRecordToLeaseSpec(ler *LeaderElectionRecord) coordinationv1.LeaseSpec {
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	leaseDurationSeconds := int32(ler.LeaseDurationSeconds)
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	leaseTransitions := int32(ler.LeaderTransitions)
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	return coordinationv1.LeaseSpec{
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		HolderIdentity:       &ler.HolderIdentity,
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		LeaseDurationSeconds: &leaseDurationSeconds,
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		AcquireTime:          &metav1.MicroTime{Time: ler.AcquireTime.Time},
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		RenewTime:            &metav1.MicroTime{Time: ler.RenewTime.Time},
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		LeaseTransitions:     &leaseTransitions,
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	}
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}
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