http callbackk

util/retry.go

@@ -0,0 +1,39 @@
+package util
+
+import (
+	"math/rand"
+	"time"
+)
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+func Retry(attempts int, sleep time.Duration, f func() error) error {
+	if err := f(); err != nil {
+		if s, ok := err.(retryStop); ok {
+			// Return the original error for later checking
+			return s.error
+		}
+
+		if attempts--; attempts > 0 {
+			// Add some randomness to prevent creating a Thundering Herd
+			jitter := time.Duration(rand.Int63n(int64(sleep)))
+			sleep = sleep + jitter/2
+
+			time.Sleep(sleep)
+			return Retry(attempts, 2*sleep, f)
+		}
+		return err
+	}
+
+	return nil
+}
+
+type retryStop struct {
+	error
+}
+
+func RetryStopErr(err error) retryStop {
+	return retryStop{err}
+}