105 lines
3.0 KiB
Go
105 lines
3.0 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 etcd3
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import (
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"sync"
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"time"
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"github.com/coreos/etcd/clientv3"
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"github.com/golang/glog"
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"golang.org/x/net/context"
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)
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const compactInterval = 10 * time.Minute
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var (
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endpointsMapMu sync.Mutex
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endpointsMap map[string]struct{}
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)
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func init() {
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endpointsMap = make(map[string]struct{})
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}
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// StartCompactor starts a compactor in the background in order to compact keys
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// older than fixed time.
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// We need to compact keys because we can't let on disk data grow forever.
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// We save the most recent 10 minutes data. It should be enough for slow watchers and to tolerate burst.
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// TODO: We might keep a longer history (12h) in the future once storage API can take
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// advantage of multi-version key.
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func StartCompactor(ctx context.Context, client *clientv3.Client) {
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endpointsMapMu.Lock()
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defer endpointsMapMu.Unlock()
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// We can't have multiple compaction jobs for the same cluster.
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// Currently we rely on endpoints to differentiate clusters.
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var emptyStruct struct{}
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for _, ep := range client.Endpoints() {
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if _, ok := endpointsMap[ep]; ok {
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glog.V(4).Infof("compactor already exists for endpoints %v", client.Endpoints())
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return
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}
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}
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for _, ep := range client.Endpoints() {
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endpointsMap[ep] = emptyStruct
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}
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go compactor(ctx, client, compactInterval)
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}
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// compactor periodically compacts historical versions of keys in etcd.
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// After compaction, old versions of keys set before given interval will be gone.
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// Any API call for the old versions of keys will return error.
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// interval: the interval between each compaction. The first compaction happens after "interval".
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func compactor(ctx context.Context, client *clientv3.Client, interval time.Duration) {
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var curRev int64
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var err error
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for {
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select {
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case <-time.After(interval):
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case <-ctx.Done():
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return
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}
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curRev, err = compact(ctx, client, curRev)
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if err != nil {
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glog.Error(err)
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continue
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}
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}
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}
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// compact compacts etcd store and returns current rev.
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// If it couldn't get current revision, the old rev will be returned.
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func compact(ctx context.Context, client *clientv3.Client, oldRev int64) (int64, error) {
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resp, err := client.Get(ctx, "/")
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if err != nil {
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return oldRev, err
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}
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curRev := resp.Header.Revision
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if oldRev == 0 {
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return curRev, nil
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}
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err = client.Compact(ctx, oldRev)
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if err != nil {
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return curRev, err
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}
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glog.Infof("etcd: Compacted rev %d, endpoints %v", oldRev, client.Endpoints())
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return curRev, nil
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}
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