package retry
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//go:generate go run github.com/v2fly/v2ray-core/v5/common/errors/errorgen
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import (
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"time"
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)
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var ErrRetryFailed = newError("all retry attempts failed")
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// Strategy is a way to retry on a specific function.
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type Strategy interface {
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// On performs a retry on a specific function, until it doesn't return any error.
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On(func() error) error
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}
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type retryer struct {
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totalAttempt int
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nextDelay func() uint32
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}
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// On implements Strategy.On.
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func (r *retryer) On(method func() error) error {
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attempt := 0
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accumulatedError := make([]error, 0, r.totalAttempt)
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for attempt < r.totalAttempt {
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err := method()
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if err == nil {
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return nil
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}
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numErrors := len(accumulatedError)
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if numErrors == 0 || err.Error() != accumulatedError[numErrors-1].Error() {
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accumulatedError = append(accumulatedError, err)
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}
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delay := r.nextDelay()
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time.Sleep(time.Duration(delay) * time.Millisecond)
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attempt++
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}
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return newError(accumulatedError).Base(ErrRetryFailed)
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}
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// Timed returns a retry strategy with fixed interval.
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func Timed(attempts int, delay uint32) Strategy {
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return &retryer{
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totalAttempt: attempts,
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nextDelay: func() uint32 {
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return delay
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},
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}
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}
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func ExponentialBackoff(attempts int, delay uint32) Strategy {
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nextDelay := uint32(0)
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return &retryer{
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totalAttempt: attempts,
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nextDelay: func() uint32 {
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r := nextDelay
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nextDelay += delay
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return r
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},
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}
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}
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