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