82 lines
1.8 KiB
Go
82 lines
1.8 KiB
Go
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package retry
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import (
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"context"
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"fmt"
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"log"
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"time"
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)
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// Config represents a retry config
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type Config struct {
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// The operation will be retried until StartTimeout has elapsed. 0 means
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// forever.
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StartTimeout time.Duration
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// RetryDelay gives the time elapsed after a failure and before we try
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// again. Returns 2s by default.
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RetryDelay func() time.Duration
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// Max number of retries, 0 means infinite
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Tries int
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// ShouldRetry tells wether error should be retried. Nil defaults to always
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// true.
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ShouldRetry func(error) bool
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}
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// Run fn until context is cancelled up until StartTimeout time has passed.
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func (cfg Config) Run(ctx context.Context, fn func(context.Context) error) error {
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retryDelay := func() time.Duration { return 2 * time.Second }
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if cfg.RetryDelay != nil {
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retryDelay = cfg.RetryDelay
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}
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shouldRetry := func(error) bool { return true }
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if cfg.ShouldRetry != nil {
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shouldRetry = cfg.ShouldRetry
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}
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var startTimeout <-chan time.Time // nil chans never unlock !
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if cfg.StartTimeout != 0 {
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startTimeout = time.After(cfg.StartTimeout)
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}
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for try := 0; ; try++ {
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var err error
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if cfg.Tries != 0 && try == cfg.Tries {
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return err
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}
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if err = fn(ctx); err == nil {
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return nil
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}
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if !shouldRetry(err) {
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return err
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}
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log.Print(fmt.Errorf("Retryable error: %s", err))
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select {
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case <-ctx.Done():
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return err
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case <-startTimeout:
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return err
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default:
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time.Sleep(retryDelay())
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}
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}
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}
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type Backoff struct {
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InitialBackoff time.Duration
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MaxBackoff time.Duration
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Multiplier float64
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}
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func (lb *Backoff) Linear() time.Duration {
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wait := lb.InitialBackoff
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lb.InitialBackoff = time.Duration(lb.Multiplier * float64(lb.InitialBackoff))
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if lb.MaxBackoff != 0 && lb.InitialBackoff > lb.MaxBackoff {
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lb.InitialBackoff = lb.MaxBackoff
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}
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return wait
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}
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