fallback first iteration + conditions

apis/keda/v1alpha1/condition_types.go

@@ -32,6 +32,8 @@ const (
 	ConditionActive ConditionType = "Active"
 	// ConditionFallback specifies that the resource has a fallback active.
 	ConditionFallback ConditionType = "Fallback"
+	// ConditionExternalFallback specifies that the resource has external fallback active.
+	ConditionExternalFallback ConditionType = "ExternalFallback"
 	// ConditionPaused specifies that the resource is paused.
 	ConditionPaused ConditionType = "Paused"
 )
@@ -88,6 +90,8 @@ func (c *Conditions) AreInitialized() bool {
 	foundActive := false
 	foundFallback := false
 	foundPaused := false
+	foundExternalFallback := false
+
 	if *c != nil {
 		for _, condition := range *c {
 			if condition.Type == ConditionReady {
@@ -113,14 +117,19 @@ func (c *Conditions) AreInitialized() bool {
 				break
 			}
 		}
+		for _, condition := range *c {
+			if condition.Type == ConditionExternalFallback {
+				foundExternalFallback = true
+			}
+		}
 	}
 
-	return foundReady && foundActive && foundFallback && foundPaused
+	return foundReady && foundActive && foundFallback && foundPaused && foundExternalFallback
 }
 
 // GetInitializedConditions returns Conditions initialized to the default -> Status: Unknown
 func GetInitializedConditions() *Conditions {
-	return &Conditions{{Type: ConditionReady, Status: metav1.ConditionUnknown}, {Type: ConditionActive, Status: metav1.ConditionUnknown}, {Type: ConditionFallback, Status: metav1.ConditionUnknown}, {Type: ConditionPaused, Status: metav1.ConditionUnknown}}
+	return &Conditions{{Type: ConditionReady, Status: metav1.ConditionUnknown}, {Type: ConditionActive, Status: metav1.ConditionUnknown}, {Type: ConditionFallback, Status: metav1.ConditionUnknown}, {Type: ConditionPaused, Status: metav1.ConditionUnknown}, {Type: ConditionExternalFallback, Status: metav1.ConditionUnknown}}
 }
 
 // IsTrue is true if the condition is True
@@ -171,6 +180,14 @@ func (c *Conditions) SetFallbackCondition(status metav1.ConditionStatus, reason
 	c.setCondition(ConditionFallback, status, reason, message)
 }
 
+// SetExternalFallbackCondition modifies ExternalFallback Condition according to input parameters (for ExternalCalculators)
+func (c *Conditions) SetExternalFallbackCondition(status metav1.ConditionStatus, reason string, message string) {
+	if *c == nil {
+		c = GetInitializedConditions()
+	}
+	c.setCondition(ConditionExternalFallback, status, reason, message)
+}
+
 // SetPausedCondition modifies Paused Condition according to input parameters
 func (c *Conditions) SetPausedCondition(status metav1.ConditionStatus, reason string, message string) {
 	if *c == nil {

apis/keda/v1alpha1/scaledobject_types.go

@@ -115,6 +115,8 @@ type ComplexScalingLogic struct {
 	Formula string `json:"formula,omitempty"`
 	// +optional
 	Target string `json:"target,omitempty"`
+	// +optional
+	Fallback *Fallback `json:"fallback,omitempty"`
 }
 
 // ExternalCalculation structure describes name and URL of a gRPC server
@@ -125,8 +127,6 @@ type ExternalCalculation struct {
 	Name    string `json:"name"`
 	URL     string `json:"url"`
 	Timeout string `json:"timeout"`
-	// +optional
-	FallbackReplicas int32 `json:"fallbackReplicas,omitempty"`
 }
 
 // HorizontalPodAutoscalerConfig specifies horizontal scale config

pkg/externalscaling/client.go

@@ -3,7 +3,6 @@ package externalscaling
 import (
 	"context"
 	"fmt"
-	"strconv"
 	"time"
 
 	"github.com/go-logr/logr"
@@ -13,7 +12,6 @@ import (
 	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/metrics/pkg/apis/external_metrics"
 
-	"github.com/kedacore/keda/v2/apis/keda/v1alpha1"
 	cl "github.com/kedacore/keda/v2/pkg/externalscaling/api"
 )
 
@@ -103,38 +101,3 @@ func ConvertFromGeneratedStruct(inExternal *cl.MetricsList) []external_metrics.E
 	}
 	return outK8sList
 }
-
-// Fallback function returns generated structure for metrics if its given in
-// scaledObject. Returned structure has one metric value. Name of the metric is
-// either name of already existing metric if its the only one, otherwise it will
-// be named after current external calculator
-func Fallback(err error, list *cl.MetricsList, ec v1alpha1.ExternalCalculation, targetValueString string, logger logr.Logger) (*cl.MetricsList, error) {
-	if err == nil {
-		// return unmodified list when no error exists
-		return list, nil
-	}
-
-	targetValue, errParse := strconv.ParseFloat(targetValueString, 64)
-	if errParse != nil {
-		return nil, errParse
-	}
-
-	listOut := cl.MetricsList{}
-	// if list contains only one metric, return the same one (by name) otherwise
-	// if multiple metrics are given, return just one with the name of ExternalCalculator
-	metricName := ""
-	if len(list.MetricValues) == 1 {
-		metricName = list.MetricValues[0].Name
-	} else {
-		metricName = ec.Name
-	}
-	// returned metrics
-	metricValue := int64((targetValue * 1000) * float64(ec.FallbackReplicas))
-	metric := cl.Metric{
-		Name:  metricName,
-		Value: float32(metricValue),
-	}
-	listOut.MetricValues = append(listOut.MetricValues, &metric)
-	logger.Info(fmt.Sprintf("surpressing error for externalCalculator '%s' by activating its fallback", ec.Name))
-	return &listOut, nil
-}