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- package aws
-
- import (
- "time"
- )
-
- // AttemptStrategy represents a strategy for waiting for an action
- // to complete successfully. This is an internal type used by the
- // implementation of other goamz packages.
- type AttemptStrategy struct {
- Total time.Duration // total duration of attempt.
- Delay time.Duration // interval between each try in the burst.
- Min int // minimum number of retries; overrides Total
- }
-
- type Attempt struct {
- strategy AttemptStrategy
- last time.Time
- end time.Time
- force bool
- count int
- }
-
- // Start begins a new sequence of attempts for the given strategy.
- func (s AttemptStrategy) Start() *Attempt {
- now := time.Now()
- return &Attempt{
- strategy: s,
- last: now,
- end: now.Add(s.Total),
- force: true,
- }
- }
-
- // Next waits until it is time to perform the next attempt or returns
- // false if it is time to stop trying.
- func (a *Attempt) Next() bool {
- now := time.Now()
- sleep := a.nextSleep(now)
- if !a.force && !now.Add(sleep).Before(a.end) && a.strategy.Min <= a.count {
- return false
- }
- a.force = false
- if sleep > 0 && a.count > 0 {
- time.Sleep(sleep)
- now = time.Now()
- }
- a.count++
- a.last = now
- return true
- }
-
- func (a *Attempt) nextSleep(now time.Time) time.Duration {
- sleep := a.strategy.Delay - now.Sub(a.last)
- if sleep < 0 {
- return 0
- }
- return sleep
- }
-
- // HasNext returns whether another attempt will be made if the current
- // one fails. If it returns true, the following call to Next is
- // guaranteed to return true.
- func (a *Attempt) HasNext() bool {
- if a.force || a.strategy.Min > a.count {
- return true
- }
- now := time.Now()
- if now.Add(a.nextSleep(now)).Before(a.end) {
- a.force = true
- return true
- }
- return false
- }
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