443d58e40a
Alpha implementation of the Dynamic Kubelet Configuration feature. See the proposal doc in #29459.
85 lines
3.4 KiB
Go
85 lines
3.4 KiB
Go
/*
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Copyright 2017 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 store
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import (
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"fmt"
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"time"
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"k8s.io/kubernetes/pkg/kubelet/kubeletconfig/checkpoint"
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)
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// Store saves checkpoints and information about which is the current and last-known-good checkpoint to a storage layer
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type Store interface {
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// Initialize sets up the storage layer
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Initialize() error
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// Exists returns true if a checkpoint with `uid` exists in the store, false otherwise
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Exists(uid string) (bool, error)
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// Save saves the checkpoint to the storage layer
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Save(c checkpoint.Checkpoint) error
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// Load loads the checkpoint with UID `uid` from the storage layer, or returns an error if the checkpoint does not exist
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Load(uid string) (checkpoint.Checkpoint, error)
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// CurrentModified returns the last time that the current UID was set
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CurrentModified() (time.Time, error)
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// Current returns the source that points to the current checkpoint, or nil if no current checkpoint is set
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Current() (checkpoint.RemoteConfigSource, error)
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// LastKnownGood returns the source that points to the last-known-good checkpoint, or nil if no last-known-good checkpoint is set
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LastKnownGood() (checkpoint.RemoteConfigSource, error)
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// SetCurrent saves the source that points to the current checkpoint, set to nil to unset
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SetCurrent(source checkpoint.RemoteConfigSource) error
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// SetCurrentUpdated is similar to SetCurrent, but also returns whether the current checkpoint changed as a result
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SetCurrentUpdated(source checkpoint.RemoteConfigSource) (bool, error)
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// SetLastKnownGood saves the source that points to the last-known-good checkpoint, set to nil to unset
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SetLastKnownGood(source checkpoint.RemoteConfigSource) error
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// Reset unsets the current and last-known-good UIDs and returns whether the current UID was unset as a result of the reset
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Reset() (bool, error)
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}
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// reset is a helper for implementing Reset, which can be implemented in terms of Store methods
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func reset(s Store) (bool, error) {
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if err := s.SetLastKnownGood(nil); err != nil {
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return false, fmt.Errorf("failed to reset last-known-good UID in checkpoint store, error: %v", err)
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}
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updated, err := s.SetCurrentUpdated(nil)
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if err != nil {
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return false, fmt.Errorf("failed to reset current UID in checkpoint store, error: %v", err)
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}
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return updated, nil
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}
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// setCurrentUpdated is a helper for implementing SetCurrentUpdated, which can be implemented in terms of Store methods
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func setCurrentUpdated(s Store, source checkpoint.RemoteConfigSource) (bool, error) {
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cur, err := s.Current()
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if err != nil {
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return false, err
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}
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// if both are nil, no need to update
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if cur == nil && source == nil {
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return false, nil
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}
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// if UIDs match, no need to update
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if (source != nil && cur != nil) && cur.UID() == source.UID() {
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return false, nil
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}
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// update the source
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if err := s.SetCurrent(source); err != nil {
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return false, err
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}
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return true, nil
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}
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