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|
package key
import (
"errors"
"time"
"github.com/jonboulle/clockwork"
"github.com/coreos/pkg/timeutil"
)
func NewKeySetSyncer(r ReadableKeySetRepo, w WritableKeySetRepo) *KeySetSyncer {
return &KeySetSyncer{
readable: r,
writable: w,
clock: clockwork.NewRealClock(),
}
}
type KeySetSyncer struct {
readable ReadableKeySetRepo
writable WritableKeySetRepo
clock clockwork.Clock
}
func (s *KeySetSyncer) Run() chan struct{} {
stop := make(chan struct{})
go func() {
var failing bool
var next time.Duration
for {
exp, err := syncKeySet(s.readable, s.writable, s.clock)
if err != nil || exp == 0 {
if !failing {
failing = true
next = time.Second
} else {
next = timeutil.ExpBackoff(next, time.Minute)
}
if exp == 0 {
log.Errorf("Synced to already expired key set, retrying in %v: %v", next, err)
} else {
log.Errorf("Failed syncing key set, retrying in %v: %v", next, err)
}
} else {
failing = false
next = exp / 2
log.Infof("Synced key set, checking again in %v", next)
}
select {
case <-s.clock.After(next):
continue
case <-stop:
return
}
}
}()
return stop
}
func Sync(r ReadableKeySetRepo, w WritableKeySetRepo) (time.Duration, error) {
return syncKeySet(r, w, clockwork.NewRealClock())
}
// syncKeySet copies the keyset from r to the KeySet at w and returns the duration in which the KeySet will expire.
// If keyset has already expired, returns a zero duration.
func syncKeySet(r ReadableKeySetRepo, w WritableKeySetRepo, clock clockwork.Clock) (exp time.Duration, err error) {
var ks KeySet
ks, err = r.Get()
if err != nil {
return
}
if ks == nil {
err = errors.New("no source KeySet")
return
}
if err = w.Set(ks); err != nil {
return
}
now := clock.Now()
if ks.ExpiresAt().After(now) {
exp = ks.ExpiresAt().Sub(now)
}
return
}
|
