intervalok

A Go library for series of time intervals: schedules that resolve in time.Duration, ready for time.Sleep, retry loops, and schedulers.

Each series type shares the same duration-first shape: given a reference time.Time, it tells you how long until the next occurrence (and, where it makes sense, how long since the previous one). The calendar or backoff math stays internal; the public contract is a duration.

Packages

• cron — parses standard cron expressions and resolves the next/previous occurrence, in both absolute time and duration form.
• backoff — pluggable exponential backoff strategies, with optional jitter, for retry policies.

backoff

bi := backoff.NewFullJitterBackoffInterval(500 * time.Millisecond)
for {
    if err := doSomething(); err != nil {
        time.Sleep(bi.Next())
        continue
    }
    break
}

BackoffInterval is a generic retry-delay engine: pluggable nextFunc/ resetFunc pairs drive the sequence, so new strategies plug in without new concrete types. Jitter strategies follow the AWS Architecture Blog reference "Exponential Backoff and Jitter":

Strategy	Formula	Constructor
FullJitter (default)	random(0, interval)	NewFullJitterBackoffInterval
EqualJitter	interval/2 + random(0, interval/2)	NewEqualJitterBackoffInterval
DecorrelatedJitter	min(cap, random(base, prevSleep*3))	NewDecorrelatedBackoffInterval
PercentJitter	interval ± Randomizer% (this package's own; not from the AWS reference)	NewPercentJitterBackoffInterval

DecorrelatedJitter is structurally different from the other three: its recurrence depends on the previously returned sleep instead of a deterministic exponential ramp, so it runs as its own engine rather than a jitter strategy plugged into the exponential one.

WrapError attaches the current backoff interval to an error, without losing the original via errors.Is/errors.As:

if err != nil {
    return bi.WrapError(err)
}

Status

Early development. APIs may change without notice until a first tagged release.

License

MIT — see LICENSE.