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