89 lines
1.9 KiB
Go
89 lines
1.9 KiB
Go
package transport
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import (
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"math"
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"math/rand"
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"time"
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)
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type RetryManager struct {
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config *RetryConfig
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retryCount int
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saturation int
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}
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func NewRetryManager(config *RetryConfig) *RetryManager {
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// saturationCount: retry count at which base delay meets or exceeds MaxDelay.
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// Conservative by two to preserve jitter variance near the boundary.
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saturation := 0
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if config != nil &&
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config.InitialDelay > 0 &&
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config.InitialDelay <= config.MaxDelay {
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ratio := float64(config.MaxDelay) / float64(config.InitialDelay)
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saturation = int(math.Ceil(math.Log2(ratio))) + 2
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}
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return &RetryManager{
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config: config,
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retryCount: 0,
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saturation: saturation,
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}
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}
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func (r *RetryManager) ShouldRetry() bool {
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if r.config == nil {
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return false
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}
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if r.config.MaxRetries > 0 && r.retryCount >= r.config.MaxRetries {
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return false
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}
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return true
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}
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func (r *RetryManager) CalculateDelay() time.Duration {
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if r.config == nil {
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return time.Second
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}
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// First attempt: immediate retry
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if r.retryCount == 0 {
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return 0
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}
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// if saturation is reached, calculated backoff will always be higher than
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// the maximum delay
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if r.config != nil && r.retryCount >= r.saturation {
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return r.config.MaxDelay
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}
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// Exponential backoff: InitialDelay * 2^(attempts-1)
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shift := r.retryCount - 1
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if shift > 62 {
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shift = 62
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} // prevent overflow
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backoffMultiplier := float64(int64(1) << shift)
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baseDelay := float64(r.config.InitialDelay) * backoffMultiplier
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// Apply jitter: delay * (1 + jitterFactor * (random - 0.5))
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random := rand.Float64()
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jitterMultiplier := 1 + r.config.JitterFactor*(random-0.5)
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delay := time.Duration(baseDelay * jitterMultiplier)
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// Cap at MaxDelay
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if delay > r.config.MaxDelay {
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delay = r.config.MaxDelay
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}
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return delay
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}
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func (m *RetryManager) RecordRetry() {
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m.retryCount++
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}
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func (m *RetryManager) RetryCount() int {
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return m.retryCount
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}
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