feat: introduce GenerateNextReconcileTimer interface and adjust default reconcile time function (#191)

* feat: introduce `GenerateNextReconcileTimer` interface and adjust default reconcile time function

* chore: adjust implementation to take the value of the GenerateNextReconcileTime as a seed for randomness rather than a hardcoded valu

* chore: rework implementation fo getNextReconcileTime

Author: aaronschweig

controller/lifecycle/spread.go

@@ -2,7 +2,7 @@ package lifecycle
 
 import (
 	"fmt"
-	"math/rand"
+	"math/rand/v2"
 	"time"
 
 	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -28,9 +28,20 @@ type RuntimeObjectSpreadReconcileStatus interface {
 	SetNextReconcileTime(time v1.Time)
 }
 
-// getNextReconcileTime returns a random time between 12 and 24 hours
-func getNextReconcileTime() time.Duration {
-	return 12*time.Hour + time.Duration(rand.Int63n(12*60))*time.Minute
+type GenerateNextReconcileTimer interface {
+	GenerateNextReconcileTime() time.Duration
+}
+
+const defaultMaxReconcileDuration = 24 * time.Hour
+
+// getNextReconcileTime returns a random time between [maxReconcileTime]/2 and [maxReconcileTime] hours
+func getNextReconcileTime(maxReconcileTime time.Duration) time.Duration {
+
+	minTime := maxReconcileTime.Minutes() / 2
+
+	jitter := rand.Int64N(int64(minTime))
+
+	return time.Duration(jitter+int64(minTime)) * time.Minute
 }
 
 // onNextReconcile is a helper function to set the next reconcile time and return the requeueAfter time
@@ -42,7 +53,14 @@ func onNextReconcile(instanceStatusObj RuntimeObjectSpreadReconcileStatus, log *
 
 // setNextReconcileTime calculates and sets the next reconcile time for the instance
 func setNextReconcileTime(instanceStatusObj RuntimeObjectSpreadReconcileStatus, log *logger.Logger) {
-	nextReconcileTime := getNextReconcileTime()
+
+	var border = defaultMaxReconcileDuration
+	if in, ok := instanceStatusObj.(GenerateNextReconcileTimer); ok {
+		border = in.GenerateNextReconcileTime()
+	}
+
+	nextReconcileTime := getNextReconcileTime(border)
+
 	log.Debug().Int64("minutes-till-next-execution", int64(nextReconcileTime.Minutes())).Msg("Setting next reconcile time for the instance")
 	instanceStatusObj.SetNextReconcileTime(v1.NewTime(time.Now().Add(nextReconcileTime)))
 }

controller/lifecycle/spread_test.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
 	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	"github.com/openmfp/golang-commons/controller/testSupport"
@@ -15,12 +16,12 @@ func TestGetNextReconcilationTime(t *testing.T) {
 	expectedEarliest := 12 * time.Hour
 	expectedLatest := 24 * time.Hour
 
-	actual := getNextReconcileTime()
+	actual := getNextReconcileTime(defaultMaxReconcileDuration)
 	if actual < expectedEarliest || actual > expectedLatest {
 		t.Errorf("Expected time between %v and %v, but got %v", expectedEarliest, expectedLatest, actual)
 	}
 
-	actual2 := getNextReconcileTime()
+	actual2 := getNextReconcileTime(defaultMaxReconcileDuration)
 	if actual2 < expectedEarliest || actual2 > expectedLatest {
 		t.Errorf("Expected time between %v and %v, but got %v", expectedEarliest, expectedLatest, actual)
 	}
@@ -52,6 +53,28 @@ func TestOnNextReconcile(t *testing.T) {
 	assert.Contains(t, messages[0].Message, "no processing needed")
 }
 
+type testInstance struct {
+	mock.Mock
+	*implementingSpreadReconciles
+}
+
+func (t *testInstance) GenerateNextReconcileTime() time.Duration {
+	args := t.Called()
+	return args.Get(0).(time.Duration)
+}
+
+func TestGenerateNextReconcileTimer(t *testing.T) {
+	instance := &testInstance{
+		implementingSpreadReconciles: &implementingSpreadReconciles{testSupport.TestApiObject{}},
+	}
+
+	instance.On("GenerateNextReconcileTime").Return(10 * time.Minute)
+
+	setNextReconcileTime(instance, testlogger.New().Logger)
+
+	assert.True(t, instance.AssertCalled(t, "GenerateNextReconcileTime"))
+}
+
 func TestUpdateObservedGeneration(t *testing.T) {
 	instanceStatusObj := testSupport.TestStatus{
 		ObservedGeneration: 0,