mz.attahri.com/code/backoff

Backoff

Package backoff implements backoff logic for retry loops.

It provides a Generator that produces a sequence of time.Duration values using configurable step functions: Fixed, Linear, Incremental, Exponential, and Jitter.

Usage

Exponential Backoff

gen := backoff.New(time.Second, 30*time.Second, backoff.Exponential(2))

for attempt := range gen.Values() {
    if err := doSomething(); err == nil {
        break
    }
    time.Sleep(attempt)
}
// Produces: 1s, 2s, 4s, 8s, 16s, 30s, 30s, ...

With Jitter

Jitter is useful in distributed systems to avoid thundering herd problems.

gen := backoff.New(
    time.Second,
    30*time.Second,
    backoff.Jitter(backoff.Exponential(2), 0.5),
)

for i := 0; i < maxRetries; i++ {
    if err := doSomething(); err == nil {
        break
    }
    time.Sleep(gen.Next())
}
// Produces values in range: [0.5s-1s], [1s-2s], [2s-4s], ...

Linear Backoff

gen := backoff.New(time.Second, 10*time.Second, backoff.Linear(2*time.Second))
// Produces: 1s, 3s, 5s, 7s, 9s, 10s, 10s, ...

Fixed Backoff

gen := backoff.New(time.Second, 0, backoff.Fixed(5*time.Second))
// Produces: 5s, 5s, 5s, ...

Step Functions

Function	Description
Fixed(d)	Always returns d
Linear(d)	Adds d each iteration: base, base+d, base+2d, ...
Incremental(m)	Multiplies base by count: base, base*m, base*2m, ...
Exponential(f)	Exponential growth: base, base*f, base*f^2, ...
Jitter(fn, factor)	Wraps any step function with randomized jitter in [d-factor*d, d]

Contributions

Contributions are welcome via Pull Requests.