luxolus/open-vault
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Use a more heurstic function for calculating sleep backoff

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This commit is contained in:
Seth Vargo 2017-06-26 16:22:18 -05:00
parent f18b7fd6dc
commit 207e1d5dd3
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1 changed files with 26 additions and 7 deletions
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33
api/renewer.go
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@ -187,19 +187,20 @@ func (r *Renewer) renewAuth() error {
return ErrRenewerNotRenewable return ErrRenewerNotRenewable
} }
// Grab the lease duration - note that we grab the auth lease duration, not // Grab the lease duration and sleep duration - note that we grab the auth
// the secret lease duration. // lease duration, not the secret lease duration.
leaseDuration := time.Duration(renewal.Auth.LeaseDuration) * time.Second leaseDuration := time.Duration(renewal.Auth.LeaseDuration) * time.Second
sleepDuration := sleepDuration(leaseDuration)
// If we are within grace, return now. // If we are within grace, return now.
if leaseDuration <= r.grace { if leaseDuration <= r.grace || sleepDuration <= r.grace {
return nil return nil
} }
select { select {
case <-r.stopCh: case <-r.stopCh:
return nil return nil
case <-time.After(time.Duration(leaseDuration/2.0) * time.Second): case <-time.After(sleepDuration):
continue continue
} }
} }
@ -243,19 +244,37 @@ func (r *Renewer) renewLease() error {
return ErrRenewerNotRenewable return ErrRenewerNotRenewable
} }
// Grab the lease duration // Grab the lease duration and sleep duration
leaseDuration := time.Duration(renewal.LeaseDuration) * time.Second leaseDuration := time.Duration(renewal.LeaseDuration) * time.Second
sleepDuration := sleepDuration(leaseDuration)
// If we are within grace, return now. // If we are within grace, return now.
if leaseDuration <= r.grace { if leaseDuration <= r.grace || sleepDuration <= r.grace {
return nil return nil
} }
select { select {
case <-r.stopCh: case <-r.stopCh:
return nil return nil
case <-time.After(time.Duration(leaseDuration/2.0) * time.Second): case <-time.After(sleepDuration):
continue continue
} }
} }
} }
// sleepDuration calculates the time to sleep given the base lease duration. The
// base is the resulting lease duration. It will be reduced to 1/3 and
// multiplied by a random float between 0.0 and 1.0. This extra randomness
// prevents multiple clients from all trying to renew simultaneously.
func sleepDuration(base time.Duration) time.Duration {
sleep := float64(base)
// Renew at 1/3 the remaining lease. This will give us an opportunity to retry
// at least one more time should the first renewal fail.
sleep = sleep / 3.0
// Use a randomness so many clients do not hit Vault simultaneously.
sleep = sleep * rand.Float64()
return time.Duration(sleep) * time.Second
}