New backoff (#1153)

* new backoff function

* use backoff from util/backoff

* remove reset atemts

* change comment

* fmt

client/backoff.go

@@ -2,13 +2,13 @@ package client
 
 import (
 	"context"
-	"math"
 	"time"
+
+	"github.com/micro/go-micro/v2/util/backoff"
 )
 
 type BackoffFunc func(ctx context.Context, req Request, attempts int) (time.Duration, error)
 
-// exponential backoff is a function x^e multiplied by a factor of 0.1 second.
 func exponentialBackoff(ctx context.Context, req Request, attempts int) (time.Duration, error) {
-	return time.Duration(math.Pow(float64(attempts), math.E)) * time.Millisecond * 100, nil
+	return backoff.Do(attempts), nil
 }

network/default.go

@@ -225,9 +225,6 @@ func (n *network) acceptNetConn(l tunnel.Listener, recv chan *message) {
 			sleep := backoff.Do(i)
 			log.Debugf("Network tunnel [%s] accept error: %v, backing off for %v", ControlChannel, err, sleep)
 			time.Sleep(sleep)
-			if i > 5 {
-				i = 0
-			}
 			i++
 			continue
 		}
@@ -255,10 +252,6 @@ func (n *network) acceptCtrlConn(l tunnel.Listener, recv chan *message) {
 			sleep := backoff.Do(i)
 			log.Debugf("Network tunnel [%s] accept error: %v, backing off for %v", ControlChannel, err, sleep)
 			time.Sleep(sleep)
-			if i > 5 {
-				// reset the counter
-				i = 0
-			}
 			i++
 			continue
 		}
@@ -1572,11 +1565,6 @@ func (n *network) connect() {
 		case <-time.After(time.Second + backoff.Do(attempts)):
 			// we have to try again
 			attempts++
-
-			// reset attempts 5 == ~2mins
-			if attempts > 5 {
-				attempts = 0
-			}
 		}
 	}
 }

util/backoff/backoff.go

@@ -6,9 +6,11 @@ import (
 	"time"
 )
 
+// Do is a function x^e multiplied by a factor of 0.1 second.
+// Result is limited to 2 minute.
 func Do(attempts int) time.Duration {
-	if attempts == 0 {
-		return time.Duration(0)
+	if attempts > 13 {
+		return 2 * time.Minute
 	}
-	return time.Duration(math.Pow(10, float64(attempts))) * time.Millisecond
+	return time.Duration(math.Pow(float64(attempts), math.E)) * time.Millisecond * 100
 }