backoff strategy factory constructors take sources instead of seeds for randomness

backoff.go

@@ -91,8 +91,8 @@ func (b *fixedBackoff) Reset() {}
 // timeUnits are the units of time the polynomial is evaluated in
 // polyCoefs is the array of polynomial coefficients from [c0, c1, ... cn]
 func NewPolynomialBackoff(min, max time.Duration, jitter Jitter,
-	timeUnits time.Duration, polyCoefs []float64, rngSeed int64) BackoffFactory {
-	rng := rand.New(&lockedSource{src: rand.NewSource(rngSeed)})
+	timeUnits time.Duration, polyCoefs []float64, rngSrc rand.Source) BackoffFactory {
+	rng := rand.New(&lockedSource{src: rngSrc})
 	return func() BackoffStrategy {
 		return &polynomialBackoff{
 			attemptBackoff: attemptBackoff{
@@ -140,8 +140,8 @@ func (b *polynomialBackoff) Delay() time.Duration {
 // jitter is the function for adding randomness around the backoff
 // timeUnits are the units of time the base^x is evaluated in
 func NewExponentialBackoff(min, max time.Duration, jitter Jitter,
-	timeUnits time.Duration, base float64, offset time.Duration, rngSeed int64) BackoffFactory {
-	rng := rand.New(&lockedSource{src: rand.NewSource(rngSeed)})
+	timeUnits time.Duration, base float64, offset time.Duration, rngSrc rand.Source) BackoffFactory {
+	rng := rand.New(&lockedSource{src: rngSrc})
 	return func() BackoffStrategy {
 		return &exponentialBackoff{
 			attemptBackoff: attemptBackoff{
@@ -176,8 +176,8 @@ func (b *exponentialBackoff) Delay() time.Duration {
 // NewExponentialDecorrelatedJitter creates a BackoffFactory with backoff of the roughly of the form base^x where x is the attempt number.
 // Delays start at the minimum duration and after each attempt delay = rand(min, delay * base), bounded by the max
 // See https://aws.amazon.com/blogs/architecture/exponential-backoff-and-jitter/ for more information
-func NewExponentialDecorrelatedJitter(min, max time.Duration, base float64, rngSeed int64) BackoffFactory {
-	rng := rand.New(&lockedSource{src: rand.NewSource(rngSeed)})
+func NewExponentialDecorrelatedJitter(min, max time.Duration, base float64, rngSrc rand.Source) BackoffFactory {
+	rng := rand.New(&lockedSource{src: rngSrc})
 	return func() BackoffStrategy {
 		return &exponentialDecorrelatedJitter{
 			randomizedBackoff: randomizedBackoff{

backoff_test.go

@@ -39,7 +39,7 @@ func TestFixedBackoff(t *testing.T) {
 }
 
 func TestPolynomialBackoff(t *testing.T) {
-	bkf := NewPolynomialBackoff(time.Second, time.Second*33, NoJitter, time.Second, []float64{0.5, 2, 3}, 0)
+	bkf := NewPolynomialBackoff(time.Second, time.Second*33, NoJitter, time.Second, []float64{0.5, 2, 3}, rand.NewSource(0))
 	b1 := bkf()
 	b2 := bkf()
 
@@ -58,7 +58,7 @@ func TestPolynomialBackoff(t *testing.T) {
 }
 
 func TestExponentialBackoff(t *testing.T) {
-	bkf := NewExponentialBackoff(time.Millisecond*650, time.Second*7, NoJitter, time.Second, 1.5, -time.Millisecond*400, 0)
+	bkf := NewExponentialBackoff(time.Millisecond*650, time.Second*7, NoJitter, time.Second, 1.5, -time.Millisecond*400, rand.NewSource(0))
 	b1 := bkf()
 	b2 := bkf()
 
@@ -125,17 +125,17 @@ func TestFullJitter(t *testing.T) {
 }
 
 func TestManyBackoffFactory(t *testing.T) {
-	rng := rand.New(rand.NewSource(0))
+	rngSource := rand.NewSource(0)
 	concurrent := 10
 
 	t.Run("Exponential", func(t *testing.T) {
 		testManyBackoffFactoryHelper(concurrent,
-			NewExponentialBackoff(time.Millisecond*650, time.Second*7, FullJitter, time.Second, 1.5, -time.Millisecond*400, rng),
+			NewExponentialBackoff(time.Millisecond*650, time.Second*7, FullJitter, time.Second, 1.5, -time.Millisecond*400, rngSource),
 		)
 	})
 	t.Run("Polynomial", func(t *testing.T) {
 		testManyBackoffFactoryHelper(concurrent,
-			NewPolynomialBackoff(time.Second, time.Second*33, NoJitter, time.Second, []float64{0.5, 2, 3}, rng),
+			NewPolynomialBackoff(time.Second, time.Second*33, NoJitter, time.Second, []float64{0.5, 2, 3}, rngSource),
 		)
 	})
 	t.Run("Fixed", func(t *testing.T) {
@@ -175,7 +175,7 @@ func testManyBackoffFactoryHelper(concurrent int, bkf BackoffFactory) {
 				}
 			}()
 
-			for i := 0; i < 5 ; i++ {
+			for i := 0; i < 5; i++ {
 				for j := 0; j < 10; j++ {
 					backoff.Delay()
 				}
@@ -188,4 +188,4 @@ func testManyBackoffFactoryHelper(concurrent int, bkf BackoffFactory) {
 	if err := errGrp.Wait(); err != nil {
 		panic(err)
 	}
-}
+}
\ No newline at end of file

backoffcache_test.go

@@ -2,6 +2,7 @@ package discovery
 
 import (
 	"context"
+	"math/rand"
 	"testing"
 	"time"
 
@@ -67,7 +68,7 @@ func TestBackoffDiscoverySingleBackoff(t *testing.T) {
 	d2 := &mockDiscoveryClient{h2, discServer}
 
 	bkf := NewExponentialBackoff(time.Millisecond*100, time.Second*10, NoJitter,
-		time.Millisecond*100, 2.5, 0, 0)
+		time.Millisecond*100, 2.5, 0, rand.NewSource(0))
 	dCache, err := NewBackoffDiscovery(d1, bkf)
 	if err != nil {
 		t.Fatal(err)
@@ -101,7 +102,7 @@ func TestBackoffDiscoveryMultipleBackoff(t *testing.T) {
 
 	// Startup delay is 0ms. First backoff after finding data is 100ms, second backoff is 250ms.
 	bkf := NewExponentialBackoff(time.Millisecond*100, time.Second*10, NoJitter,
-		time.Millisecond*100, 2.5, 0, 0)
+		time.Millisecond*100, 2.5, 0, rand.NewSource(0))
 	dCache, err := NewBackoffDiscovery(d1, bkf)
 	if err != nil {
 		t.Fatal(err)

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/libp2p/go-libp2p-peerstore v0.2.2
 	github.com/libp2p/go-libp2p-swarm v0.2.3
 	github.com/multiformats/go-multihash v0.0.13
+	golang.org/x/sync v0.0.0-20190423024810-112230192c58
 )
 
 go 1.13

go.sum

@@ -371,6 +371,7 @@ golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6Zh
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=