add support for multi-dimensional metrics

Author: jpraychev

internal/orchestrator/metrichandler.go

@@ -6,7 +6,6 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/samber/lo"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -94,16 +93,17 @@ func (h *MetricHandler) projectionsMonitor(ctx context.Context, list *unstructur
 		// Add base dimensions only if they have a non-empty value
 		h.setDataPointBaseDimensions(dataPoint)
 
-		// Add projected dimensions for this specific group
-		for _, pField := range group {
-			// Add projected dimension only if the value is non-empty and no error occurred
-			if pField.error == nil && pField.value != "" {
-				dataPoint.AddDimension(pField.name, pField.value)
-			} else {
-				// Optionally log or handle projection errors
-				recordErrors = append(recordErrors, fmt.Errorf("projection error for %s: %w", pField.name, pField.error))
+		for _, inGroup := range group {
+			for _, pField := range inGroup {
+				// Add projected dimension only if the value is non-empty and no error occurred
+				if pField.error == nil && pField.value != "" {
+					dataPoint.AddDimension(pField.name, pField.value)
+				} else {
+					// Optionally log or handle projection errors
+					recordErrors = append(recordErrors, fmt.Errorf("projection error for %s: %w", pField.name, pField.error))
+				}
 			}
-		}
+			
 		dataPoints = append(dataPoints, dataPoint)
 	}
 
@@ -158,27 +158,31 @@ func (e *projectedField) GetID() string {
 	return fmt.Sprintf("%s: %s", e.name, e.value)
 }
 
-func (h *MetricHandler) extractProjectionGroupsFrom(list *unstructured.UnstructuredList) map[string][]projectedField {
-	// note: for now we only allow one projection, so we can use the first one
-	// the reason for this is that if we have multiple projections, we need to create a cartesian product of all projections
-	// this is to be done at a later time
-	var collection []projectedField
+func (h *MetricHandler) extractProjectionGroupsFrom(list *unstructured.UnstructuredList) map[string][][]projectedField {
+	var collection [][]projectedField
 
 	for _, obj := range list.Items {
-
-		projection := lo.FirstOr(h.metric.Spec.Projections, v1alpha1.Projection{})
-
-		if projection.Name != "" && projection.FieldPath != "" {
-			name := projection.Name
-			value, found, err := nestedPrimitiveValue(obj, projection.FieldPath)
-			collection = append(collection, projectedField{name: name, value: value, found: found, error: err})
+		var fields []projectedField
+		for _, projection := range h.metric.Spec.Projections {
+			if projection.Name != "" && projection.FieldPath != "" {
+				name := projection.Name
+				value, found, err := nestedPrimitiveValue(obj, projection.FieldPath)
+				fields = append(fields, projectedField{name: name, value: value, found: found, error: err})
+			}
 		}
+		collection = append(collection, fields)
 	}
 
-	// group by the extracted values for the dimension .e.g. device: iPhone, device: Android and count them later
-	groups := lo.GroupBy(collection, func(field projectedField) string {
-		return field.GetID()
-	})
+	// Group by the combination of all projected values
+	groups := make(map[string][][]projectedField)
+	for _, fields := range collection {
+		var keyParts []string
+		for _, f := range fields {
+			keyParts = append(keyParts, fmt.Sprintf("%s: %s", f.name, f.value))
+		}
+		key := strings.Join(keyParts, ", ")
+		groups[key] = append(groups[key], fields)
+	}
 
 	return groups
 }