v5

Author: cenkalti

context.go

@@ -0,0 +1,24 @@
+package backoff
+
+// PermanentError signals that the operation should not be retried.
+type PermanentError struct {
+	Err error
+}
+
+// Permanent wraps the given err in a *PermanentError.
+func Permanent(err error) error {
+	if err == nil {
+		return nil
+	}
+	return &PermanentError{
+		Err: err,
+	}
+}
+
+func (e *PermanentError) Error() string {
+	return e.Err.Error()
+}
+
+func (e *PermanentError) Unwrap() error {
+	return e.Err
+}

context_test.go

@@ -7,31 +7,11 @@ import (
 
 func ExampleRetry() {
 	// An operation that may fail.
-	operation := func() error {
-		return nil // or an error
+	operation := func() (bool, error) {
+		return true, nil
 	}
 
-	err := Retry(operation, NewExponentialBackOff())
-	if err != nil {
-		// Handle error.
-		return
-	}
-
-	// Operation is successful.
-}
-
-func ExampleRetryContext() { // nolint: govet
-	// A context
-	ctx := context.Background()
-
-	// An operation that may fail.
-	operation := func() error {
-		return nil // or an error
-	}
-
-	b := WithContext(NewExponentialBackOff(), ctx)
-
-	err := Retry(operation, b)
+	_, err := Retry(context.TODO(), operation, WithBackOff(NewExponentialBackOff()))
 	if err != nil {
 		// Handle error.
 		return

error.go

@@ -56,131 +56,47 @@ type ExponentialBackOff struct {
 	RandomizationFactor float64
 	Multiplier          float64
 	MaxInterval         time.Duration
-	// After MaxElapsedTime the ExponentialBackOff stops.
-	// It never stops if MaxElapsedTime == 0.
-	MaxElapsedTime time.Duration
-	Clock          Clock
 
 	currentInterval time.Duration
-	startTime       time.Time
 }
 
-// Clock is an interface that returns current time for BackOff.
-type Clock interface {
-	Now() time.Time
-}
-
-// ExponentialBackOffOpts is a function type used to configure ExponentialBackOff options.
-type ExponentialBackOffOpts func(*ExponentialBackOff)
-
 // Default values for ExponentialBackOff.
 const (
 	DefaultInitialInterval     = 500 * time.Millisecond
 	DefaultRandomizationFactor = 0.5
 	DefaultMultiplier          = 1.5
 	DefaultMaxInterval         = 60 * time.Second
-	DefaultMaxElapsedTime      = 15 * time.Minute
 )
 
 // NewExponentialBackOff creates an instance of ExponentialBackOff using default values.
-func NewExponentialBackOff(opts ...ExponentialBackOffOpts) *ExponentialBackOff {
-	b := &ExponentialBackOff{
+func NewExponentialBackOff() *ExponentialBackOff {
+	return &ExponentialBackOff{
 		InitialInterval:     DefaultInitialInterval,
 		RandomizationFactor: DefaultRandomizationFactor,
 		Multiplier:          DefaultMultiplier,
 		MaxInterval:         DefaultMaxInterval,
-		MaxElapsedTime:      DefaultMaxElapsedTime,
-		Clock:               SystemClock,
-	}
-	for _, fn := range opts {
-		fn(b)
-	}
-	b.Reset()
-	return b
-}
-
-// WithInitialInterval sets the initial interval between retries.
-func WithInitialInterval(duration time.Duration) ExponentialBackOffOpts {
-	return func(ebo *ExponentialBackOff) {
-		ebo.InitialInterval = duration
-	}
-}
-
-// WithRandomizationFactor sets the randomization factor to add jitter to intervals.
-func WithRandomizationFactor(randomizationFactor float64) ExponentialBackOffOpts {
-	return func(ebo *ExponentialBackOff) {
-		ebo.RandomizationFactor = randomizationFactor
-	}
-}
-
-// WithMultiplier sets the multiplier for increasing the interval after each retry.
-func WithMultiplier(multiplier float64) ExponentialBackOffOpts {
-	return func(ebo *ExponentialBackOff) {
-		ebo.Multiplier = multiplier
-	}
-}
-
-// WithMaxInterval sets the maximum interval between retries.
-func WithMaxInterval(duration time.Duration) ExponentialBackOffOpts {
-	return func(ebo *ExponentialBackOff) {
-		ebo.MaxInterval = duration
 	}
 }
 
-// WithMaxElapsedTime sets the maximum total time for retries.
-func WithMaxElapsedTime(duration time.Duration) ExponentialBackOffOpts {
-	return func(ebo *ExponentialBackOff) {
-		ebo.MaxElapsedTime = duration
-	}
-}
-
-// WithClockProvider sets the clock used to measure time.
-func WithClockProvider(clock Clock) ExponentialBackOffOpts {
-	return func(ebo *ExponentialBackOff) {
-		ebo.Clock = clock
-	}
-}
-
-type systemClock struct{}
-
-func (t systemClock) Now() time.Time {
-	return time.Now()
-}
-
-// SystemClock implements Clock interface that uses time.Now().
-var SystemClock = systemClock{}
-
 // Reset the interval back to the initial retry interval and restarts the timer.
 // Reset must be called before using b.
 func (b *ExponentialBackOff) Reset() {
 	b.currentInterval = b.InitialInterval
-	b.startTime = b.Clock.Now()
 }
 
 // NextBackOff calculates the next backoff interval using the formula:
 //
 //	Randomized interval = RetryInterval * (1 ± RandomizationFactor)
 func (b *ExponentialBackOff) NextBackOff() time.Duration {
-	// Make sure we have not gone over the maximum elapsed time.
-	elapsed := b.GetElapsedTime()
+	if b.currentInterval == 0 {
+		b.currentInterval = b.InitialInterval
+	}
+
 	next := getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
 	b.incrementCurrentInterval()
-	if b.MaxElapsedTime != 0 && elapsed+next > b.MaxElapsedTime {
-		return Stop
-	}
 	return next
 }
 
-// GetElapsedTime returns the elapsed time since an ExponentialBackOff instance
-// is created and is reset when Reset() is called.
-//
-// The elapsed time is computed using time.Now().UnixNano(). It is
-// safe to call even while the backoff policy is used by a running
-// ticker.
-func (b *ExponentialBackOff) GetElapsedTime() time.Duration {
-	return b.Clock.Now().Sub(b.startTime)
-}
-
 // Increments the current interval by multiplying it with the multiplier.
 func (b *ExponentialBackOff) incrementCurrentInterval() {
 	// Check for overflow, if overflow is detected set the current interval to the max interval.

example_test.go

@@ -12,15 +12,13 @@ func TestBackOff(t *testing.T) {
 		testRandomizationFactor = 0.1
 		testMultiplier          = 2.0
 		testMaxInterval         = 5 * time.Second
-		testMaxElapsedTime      = 15 * time.Minute
 	)
 
 	exp := NewExponentialBackOff()
 	exp.InitialInterval = testInitialInterval
 	exp.RandomizationFactor = testRandomizationFactor
 	exp.Multiplier = testMultiplier
 	exp.MaxInterval = testMaxInterval
-	exp.MaxElapsedTime = testMaxElapsedTime
 	exp.Reset()
 
 	var expectedResults = []time.Duration{500, 1000, 2000, 4000, 5000, 5000, 5000, 5000, 5000, 5000}
@@ -52,37 +50,6 @@ func TestGetRandomizedInterval(t *testing.T) {
 	assertEquals(t, 3, getRandomValueFromInterval(0.5, 0.99, 2))
 }
 
-type TestClock struct {
-	i     time.Duration
-	start time.Time
-}
-
-func (c *TestClock) Now() time.Time {
-	t := c.start.Add(c.i)
-	c.i += time.Second
-	return t
-}
-
-func TestGetElapsedTime(t *testing.T) {
-	var exp = NewExponentialBackOff()
-	exp.Clock = &TestClock{}
-	exp.Reset()
-
-	var elapsedTime = exp.GetElapsedTime()
-	if elapsedTime != time.Second {
-		t.Errorf("elapsedTime=%d", elapsedTime)
-	}
-}
-
-func TestMaxElapsedTime(t *testing.T) {
-	var exp = NewExponentialBackOff()
-	exp.Clock = &TestClock{start: time.Time{}.Add(10000 * time.Second)}
-	// Change the currentElapsedTime to be 0 ensuring that the elapsed time will be greater
-	// than the max elapsed time.
-	exp.startTime = time.Time{}
-	assertEquals(t, Stop, exp.NextBackOff())
-}
-
 func TestBackOffOverflow(t *testing.T) {
 	var (
 		testInitialInterval time.Duration = math.MaxInt64 / 2
@@ -106,40 +73,3 @@ func assertEquals(t *testing.T, expected, value time.Duration) {
 		t.Errorf("got: %d, expected: %d", value, expected)
 	}
 }
-
-func TestNewExponentialBackOff(t *testing.T) {
-	// Create a new ExponentialBackOff with custom options
-	backOff := NewExponentialBackOff(
-		WithInitialInterval(1*time.Second),
-		WithMultiplier(2.0),
-		WithMaxInterval(10*time.Second),
-		WithMaxElapsedTime(30*time.Second),
-		WithClockProvider(SystemClock),
-	)
-
-	// Check that the backOff object is not nil
-	if backOff == nil {
-		t.Error("Expected a non-nil ExponentialBackOff object, got nil")
-	}
-
-	// Check that the custom options were applied correctly
-	if backOff.InitialInterval != 1*time.Second {
-		t.Errorf("Expected InitialInterval to be 1 second, got %v", backOff.InitialInterval)
-	}
-
-	if backOff.Multiplier != 2.0 {
-		t.Errorf("Expected Multiplier to be 2.0, got %v", backOff.Multiplier)
-	}
-
-	if backOff.MaxInterval != 10*time.Second {
-		t.Errorf("Expected MaxInterval to be 10 seconds, got %v", backOff.MaxInterval)
-	}
-
-	if backOff.MaxElapsedTime != 30*time.Second {
-		t.Errorf("Expected MaxElapsedTime to be 30 seconds, got %v", backOff.MaxElapsedTime)
-	}
-
-	if backOff.Clock != SystemClock {
-		t.Errorf("Expected Clock to be SystemClock, got %v", backOff.Clock)
-	}
-}