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30b06a83d6
The current code simply exits without continuing to renew the lease, which means participants using a slower lease duration might have to wait multiple minutes before a new leader is elected. Allow an optional flag to be set on LeaderElectionConfig that will release the lease when the calling context is cancelled. Callers *must* ensure their lease guarded code has completed before the context is cancelled, or other processes may acquire the lease before this lease has released. Add an example command that demonstrates how cancellation could be done. As a convenience to users, make event recorder optional - not all users of the lock code will need a recorder. Kubernetes-commit: 09890b6c48da8e85237a5674d6256900f482b0a5
116 lines
3.8 KiB
Go
116 lines
3.8 KiB
Go
/*
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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 resourcelock
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import (
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"fmt"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/runtime"
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corev1 "k8s.io/client-go/kubernetes/typed/core/v1"
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)
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const (
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LeaderElectionRecordAnnotationKey = "control-plane.alpha.kubernetes.io/leader"
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EndpointsResourceLock = "endpoints"
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ConfigMapsResourceLock = "configmaps"
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)
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// LeaderElectionRecord is the record that is stored in the leader election annotation.
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// This information should be used for observational purposes only and could be replaced
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// with a random string (e.g. UUID) with only slight modification of this code.
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// TODO(mikedanese): this should potentially be versioned
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type LeaderElectionRecord struct {
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// HolderIdentity is the ID that owns the lease. If empty, no one owns this lease and
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// all callers may acquire. Versions of this library prior to Kubernetes 1.14 will not
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// attempt to acquire leases with empty identities and will wait for the full lease
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// interval to expire before attempting to reacquire. This value is set to empty when
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// a client voluntarily steps down.
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HolderIdentity string `json:"holderIdentity"`
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LeaseDurationSeconds int `json:"leaseDurationSeconds"`
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AcquireTime metav1.Time `json:"acquireTime"`
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RenewTime metav1.Time `json:"renewTime"`
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LeaderTransitions int `json:"leaderTransitions"`
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}
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// EventRecorder records a change in the ResourceLock.
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type EventRecorder interface {
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Eventf(obj runtime.Object, eventType, reason, message string, args ...interface{})
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}
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// ResourceLockConfig common data that exists across different
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// resource locks
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type ResourceLockConfig struct {
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// Identity is the unique string identifying a lease holder across
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// all participants in an election.
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Identity string
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// EventRecorder is optional.
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EventRecorder EventRecorder
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}
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// Interface offers a common interface for locking on arbitrary
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// resources used in leader election. The Interface is used
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// to hide the details on specific implementations in order to allow
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// them to change over time. This interface is strictly for use
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// by the leaderelection code.
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type Interface interface {
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// Get returns the LeaderElectionRecord
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Get() (*LeaderElectionRecord, error)
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// Create attempts to create a LeaderElectionRecord
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Create(ler LeaderElectionRecord) error
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// Update will update and existing LeaderElectionRecord
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Update(ler LeaderElectionRecord) error
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// RecordEvent is used to record events
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RecordEvent(string)
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// Identity will return the locks Identity
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Identity() string
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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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Describe() string
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}
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// Manufacture will create a lock of a given type according to the input parameters
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func New(lockType string, ns string, name string, client corev1.CoreV1Interface, rlc ResourceLockConfig) (Interface, error) {
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switch lockType {
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case EndpointsResourceLock:
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return &EndpointsLock{
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EndpointsMeta: metav1.ObjectMeta{
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Namespace: ns,
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Name: name,
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},
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Client: client,
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LockConfig: rlc,
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}, nil
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case ConfigMapsResourceLock:
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return &ConfigMapLock{
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ConfigMapMeta: metav1.ObjectMeta{
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Namespace: ns,
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Name: name,
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},
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Client: client,
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LockConfig: rlc,
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}, nil
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default:
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return nil, fmt.Errorf("Invalid lock-type %s", lockType)
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}
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}
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