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backoff

backoff policy, avoid thundering herd effect. the backoff lib is concurrent-safe.

Install:

go get github.com/rfyiamcool/backoff

Desc

How to calculate the delay time

float64(b.MinDelay) * math.Pow(b.Factor, b.Attempts)

Usage:

Simple example 1

factor = 2

b := NewBackOff(
    WithMinDelay(100*time.Millisecond),
    WithMaxDelay(10*time.Second),
    WithFactor(2),
)

equals(t, b.Duration(), 100*time.Millisecond)
equals(t, b.Duration(), 200*time.Millisecond)
equals(t, b.Duration(), 400*time.Millisecond)
for index := 0; index < 100; index++ {
    b.Duration()
}

// is max
equals(t, b.Duration(), 10*time.Second)
b.Reset()
equals(t, b.Duration(), 100*time.Millisecond)

factor = 1.7

b := NewBackOff(
    WithMinDelay(100*time.Millisecond),
    WithMaxDelay(10*time.Second),
    WithFactor(1.7),
)

equals(t, b.Duration(), 100*time.Nanosecond)
equals(t, b.Duration(), 175*time.Nanosecond)
equals(t, b.Duration(), 306*time.Nanosecond)
b.Reset()
equals(t, b.Duration(), 100*time.Nanosecond)

Jitter example

enabling Jitter adds some randomization to the backoff durations.

b := NewBackOff(
    WithMinDelay(100*time.Millisecond),
    WithMaxDelay(10*time.Second),
    WithFactor(2),
    WithJitterFlag(true),
)

equals(t, b.Duration(), 100*time.Millisecond)
between(t, b.Duration(), 100*time.Millisecond, 200*time.Millisecond)
between(t, b.Duration(), 100*time.Millisecond, 400*time.Millisecond)
b.Reset()
equals(t, b.Duration(), 100*time.Millisecond)