45 lines
1.3 KiB
Go
45 lines
1.3 KiB
Go
package common
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import (
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"fmt"
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"math"
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"time"
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)
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var RetryExhaustedError error = fmt.Errorf("Function never succeeded in Retry")
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// Retry retries a function up to numTries times with exponential backoff.
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// If numTries == 0, retry indefinitely. If interval == 0, Retry will not delay retrying and there will be
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// no exponential backoff. If maxInterval == 0, maxInterval is set to +Infinity.
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// Intervals are in seconds.
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// Returns an error if initial > max intervals, if retries are exhausted, or if the passed function returns
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// an error.
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func Retry(initialInterval float64, maxInterval float64, numTries uint, function func() (bool, error)) error {
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if maxInterval == 0 {
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maxInterval = math.Inf(1)
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} else if initialInterval < 0 || initialInterval > maxInterval {
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return fmt.Errorf("Invalid retry intervals (negative or initial < max). Initial: %f, Max: %f.", initialInterval, maxInterval)
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}
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var err error
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done := false
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interval := initialInterval
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for i := uint(0); !done && (numTries == 0 || i < numTries); i++ {
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done, err = function()
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if err != nil {
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return err
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}
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if !done {
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// Retry after delay. Calculate next delay.
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time.Sleep(time.Duration(interval) * time.Second)
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interval = math.Min(interval*2, maxInterval)
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}
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}
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if !done {
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return RetryExhaustedError
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}
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return nil
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}
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