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kvstore_watcher.go
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kvstore_watcher.go
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// Copyright 2016-2017 Authors of Cilium
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"time"
"github.com/cilium/cilium/common"
"github.com/cilium/cilium/pkg/kvstore"
"github.com/cilium/cilium/pkg/policy"
log "github.com/Sirupsen/logrus"
)
// EnableKVStoreWatcher watches for kvstore changes in the common.LastFreeIDKeyPath key.
// Triggers policy updates every time the value of that key is changed.
func (d *Daemon) EnableKVStoreWatcher(maxSeconds time.Duration) {
if maxID, err := GetMaxLabelID(); err == nil {
d.setCachedMaxLabelID(maxID)
}
ch := kvstore.Client.GetWatcher(common.LastFreeLabelIDKeyPath, maxSeconds)
go func() {
for {
select {
case updates, updateOk := <-ch:
if !updateOk {
log.Debugf("Watcher for %s closed, reacquiring it", common.LastFreeLabelIDKeyPath)
ch = kvstore.Client.GetWatcher(common.LastFreeLabelIDKeyPath, maxSeconds)
}
if len(updates) != 0 {
d.setCachedMaxLabelID(updates[0])
}
d.TriggerPolicyUpdates(updates)
}
}
}()
}
// GetCachedMaxLabelID returns the cached max label ID from the last event
// received from the KVStore.
func (d *Daemon) GetCachedMaxLabelID() (policy.NumericIdentity, error) {
d.maxCachedLabelIDMU.RLock()
id := d.maxCachedLabelID
d.maxCachedLabelIDMU.RUnlock()
if id == 0 {
// FIXME: KVStore might not set up the watcher at this point
// If that's the case, we should ask directly the KVStore
// What's the maxLabelID value.
return policy.MinimalNumericIdentity, nil
}
return id, nil
}
func (d *Daemon) setCachedMaxLabelID(id policy.NumericIdentity) {
d.maxCachedLabelIDMU.Lock()
d.maxCachedLabelID = id
d.maxCachedLabelIDMU.Unlock()
}