fibonacci + golang.org/x/sync v0.3.0 => v0.5.0 (#7)

config.go

@@ -13,15 +13,21 @@ import (
 type mode byte
 
 const (
-	Simple      mode = 0
-	Linear      mode = 1
+	// Simple mode - time increases by sleep + jitter*attempt.
+	Simple mode = 0
+	// Linear mode - time increases by sleep*attempt + jitter.
+	Linear mode = 1
+	// Exponential mode - time increases by sleep*2^attempt + jitter.
 	Exponential mode = 2
+	// Fibonacci mode - time increases by sleep*fibonacci(attempt) + jitter.
+	Fibonacci mode = 3
 )
 
 const (
 	minParallel = 0
 	minCount    = 1
-	minSleep    = time.Second
+	two         = 2
+	minSleep    = time.Second / 2
 	minDuration = time.Duration(0)
 )
 
@@ -148,19 +154,27 @@ func (c *Config) isFatal(err error) (yes bool) {
 	return false
 }
 
-func ipow2(v int) (rv int64) {
-	const two = 2
-
-	return int64(math.Pow(two, float64(v)))
-}
-
 func (c *Config) stepDuration(n int) (d time.Duration) {
 	switch c.mode {
 	case Linear:
 		return c.sleep*time.Duration(n) + c.jitter
 	case Exponential:
 		return c.sleep*time.Duration(ipow2(n)) + c.jitter
+	case Fibonacci:
+		return c.sleep*time.Duration(fibonacci(n)) + c.jitter
 	}
 
 	return c.sleep + c.jitter*time.Duration(n)
 }
+
+func ipow2(v int) (rv int64) {
+	return int64(math.Pow(two, float64(v)))
+}
+
+func fibonacci(n int) int64 {
+	if n < two {
+		return int64(n)
+	}
+
+	return fibonacci(n-1) + fibonacci(n-two)
+}

config_test.go

@@ -272,6 +272,39 @@ func TestValidate(t *testing.T) {
 	}
 }
 
+func TestFibonacci(t *testing.T) {
+	t.Parallel()
+
+	var counter int
+
+	const (
+		tryMax   = 5
+		errCount = 4
+	)
+
+	try := retry.New(
+		retry.Count(tryMax),
+		retry.Mode(retry.Fibonacci),
+	)
+
+	err := try.Single("test-fibonacci", func() (err error) {
+		counter++
+
+		if counter < errCount {
+			return errFail
+		}
+
+		return nil
+	})
+	if err != nil {
+		t.FailNow()
+	}
+
+	if counter != errCount {
+		t.FailNow()
+	}
+}
+
 func TestFatal(t *testing.T) {
 	t.Parallel()
 
@@ -303,6 +336,7 @@ func TestFatal(t *testing.T) {
 	try := retry.New(
 		retry.Count(maxTries),
 		retry.Fatal(errFatal),
+		retry.Mode(retry.Fibonacci),
 	)
 
 	steps := []retry.Step{

go.mod

@@ -1,5 +1,5 @@
 module github.com/s0rg/retry
 
-go 1.20
+go 1.21.5
 
-require golang.org/x/sync v0.3.0
+require golang.org/x/sync v0.5.0

go.sum

@@ -1,2 +1,2 @@
-golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
-golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/sync v0.5.0 h1:60k92dhOjHxJkrqnwsfl8KuaHbn/5dl0lUPUklKo3qE=
+golang.org/x/sync v0.5.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=