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helpers.go
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/
helpers.go
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package consul
import (
"math/rand"
"time"
)
// DurationMinusBuffer returns a duration, minus a buffer and jitter
// subtracted from the duration. This function is used primarily for
// servicing Consul TTL Checks in advance of the TTL.
func DurationMinusBuffer(intv time.Duration, buffer time.Duration, jitter int64) time.Duration {
d := intv - buffer
if jitter == 0 {
d -= RandomStagger(d)
} else {
d -= RandomStagger(time.Duration(int64(d) / jitter))
}
return d
}
// DurationMinusBufferDomain returns the domain of valid durations from a
// call to DurationMinusBuffer. This function is used to check user
// specified input values to DurationMinusBuffer.
func DurationMinusBufferDomain(intv time.Duration, buffer time.Duration, jitter int64) (min time.Duration, max time.Duration) {
max = intv - buffer
if jitter == 0 {
min = max
} else {
min = max - time.Duration(int64(max)/jitter)
}
return min, max
}
// RandomStagger returns an interval between 0 and the duration
func RandomStagger(intv time.Duration) time.Duration {
if intv == 0 {
return 0
}
return time.Duration(uint64(rand.Int63()) % uint64(intv))
}