fix: eliminate empty tier labels in selection metrics recording

Signed-off-by: Senan Zedan <szedan@redhat.com>

Author: szedan-rh

src/semantic-router/pkg/extproc/req_filter_classification.go

@@ -116,8 +116,7 @@ func (r *OpenAIRouter) selectModelFromCandidates(modelRefs []config.ModelRef, de
 			modelRefs[i].LoRAName == result.SelectedModel {
 			logging.Infof("[ModelSelection] Selected %s (method=%s, score=%.4f, confidence=%.2f): %s",
 				result.SelectedModel, method, result.Score, result.Confidence, result.Reasoning)
-			// Record selection metrics
-			selection.RecordSelection(string(method), decisionName, result.SelectedModel, result.Score)
+			selection.RecordSelection(string(method), decisionName, result.SelectedModel, result.Tier, result.Score)
 			return &modelRefs[i], string(method)
 		}
 	}

src/semantic-router/pkg/selection/metrics.go

@@ -400,32 +400,18 @@ func IsMetricsEnabled() bool {
 	return metricsEnabled
 }
 
-// RecordSelection records a basic model selection event
-func RecordSelection(method string, decision string, model string, score float64) {
+// RecordSelection records a basic model selection event with tier label.
+func RecordSelection(method string, decision string, model string, tier AlgorithmTier, score float64) {
 	if !metricsEnabled {
 		return
 	}
 
-	ModelSelectionTotal.WithLabelValues(method, model, decision, "").Inc()
+	tierStr := string(tier)
+	ModelSelectionTotal.WithLabelValues(method, model, decision, tierStr).Inc()
 	ModelSelectionScore.WithLabelValues(method, model).Observe(score)
 	ModelSelectionHistory.WithLabelValues(method, decision).Inc()
 }
 
-// RecordSelectionFull records a model selection event with all metrics
-func RecordSelectionFull(method SelectionMethod, model string, decision string, score, confidence float64, duration time.Duration) {
-	if !metricsEnabled {
-		return
-	}
-
-	methodStr := string(method)
-
-	ModelSelectionTotal.WithLabelValues(methodStr, model, decision, "").Inc()
-	ModelSelectionDuration.WithLabelValues(methodStr, "").Observe(duration.Seconds())
-	ModelSelectionScore.WithLabelValues(methodStr, model).Observe(score)
-	ModelSelectionConfidence.WithLabelValues(methodStr, "").Observe(confidence)
-	ModelSelectionHistory.WithLabelValues(methodStr, decision).Inc()
-}
-
 // RecordEloRating records the current Elo rating for a model in a category
 func RecordEloRating(model, category string, rating float64) {
 	if !metricsEnabled {
@@ -608,15 +594,13 @@ func calculateAgreementRatio(choices []string) float64 {
 }
 
 // RecordHybridSelection records metrics for a hybrid selection including component agreement
-func RecordHybridSelection(selectedModel string, decision string, componentChoices map[string]string, score, confidence float64, duration time.Duration) {
+func RecordHybridSelection(selectedModel string, decision string, componentChoices map[string]string, tier AlgorithmTier, score, confidence float64, duration time.Duration) {
 	if !metricsEnabled {
 		return
 	}
 
-	// Record standard selection metrics
-	RecordSelectionFull(MethodHybrid, selectedModel, decision, score, confidence, duration)
+	RecordSelectionWithTier(MethodHybrid, selectedModel, decision, tier, score, confidence, duration)
 
-	// Calculate and record component agreement
 	if len(componentChoices) > 1 {
 		choices := make([]string, 0, len(componentChoices))
 		for _, model := range componentChoices {
@@ -677,7 +661,7 @@ func RecordRouterDCAffinity(model string, affinity float64) {
 // --- RL-Driven metrics recording functions ---
 
 // RecordRLSelection records a RL-driven model selection event
-func RecordRLSelection(model, category, userID string, score float64) {
+func RecordRLSelection(model, category, userID string, tier AlgorithmTier, score float64) {
 	if !metricsEnabled {
 		return
 	}
@@ -686,11 +670,11 @@ func RecordRLSelection(model, category, userID string, score float64) {
 		category = "_global"
 	}
 
-	ModelSelectionTotal.WithLabelValues("rl_driven", model, category, "experimental").Inc()
+	tierStr := string(tier)
+	ModelSelectionTotal.WithLabelValues("rl_driven", model, category, tierStr).Inc()
 	ModelSelectionScore.WithLabelValues("rl_driven", model).Observe(score)
 	ModelSelectionHistory.WithLabelValues("rl_driven", category).Inc()
 
-	// Track personalized selections
 	if userID != "" {
 		RLDrivenPersonalizedSelections.WithLabelValues(model, category).Inc()
 	}

src/semantic-router/pkg/selection/metrics_test.go

@@ -70,18 +70,10 @@ func TestRecordSelection(t *testing.T) {
 	InitializeMetrics()
 
 	// Should not panic
-	RecordSelection("elo", "tech", "llama3.2:3b", 0.85)
-	RecordSelection("router_dc", "finance", "phi4", 0.72)
-	RecordSelection("hybrid", "general", "gemma3:27b", 0.91)
-}
-
-func TestRecordSelectionFull(t *testing.T) {
-	InitializeMetrics()
-
-	// Should not panic
-	RecordSelectionFull(MethodElo, "llama3.2:3b", "tech", 0.85, 0.92, 5*time.Millisecond)
-	RecordSelectionFull(MethodRouterDC, "phi4", "finance", 0.72, 0.88, 3*time.Millisecond)
-	RecordSelectionFull(MethodHybrid, "gemma3:27b", "general", 0.91, 0.95, 10*time.Millisecond)
+	RecordSelection("elo", "tech", "llama3.2:3b", TierSupported, 0.85)
+	RecordSelection("router_dc", "finance", "phi4", TierSupported, 0.72)
+	RecordSelection("hybrid", "general", "gemma3:27b", TierSupported, 0.91)
+	RecordSelection("automix", "general", "gemma3:27b", TierExperimental, 0.91)
 }
 
 func TestRecordEloRating(t *testing.T) {
@@ -200,7 +192,7 @@ func TestRecordHybridSelection(t *testing.T) {
 	}
 
 	// Should not panic
-	RecordHybridSelection("llama3.2:3b", "tech", componentChoices, 0.85, 0.92, 10*time.Millisecond)
+	RecordHybridSelection("llama3.2:3b", "tech", componentChoices, TierSupported, 0.85, 0.92, 10*time.Millisecond)
 }
 
 func TestCalculateAgreementRatio(t *testing.T) {

src/semantic-router/pkg/selection/rl_driven.go

@@ -600,8 +600,7 @@ func (r *RLDrivenSelector) Select(ctx context.Context, selCtx *SelectionContext)
 	logging.Infof("[RLDrivenSelector] Selected %s (score=%.4f, confidence=%.2f)",
 		selectedModel.Model, selectedScore, confidence)
 
-	// Record metrics
-	RecordRLSelection(selectedModel.Model, selCtx.DecisionName, selCtx.UserID, selectedScore)
+	RecordRLSelection(selectedModel.Model, selCtx.DecisionName, selCtx.UserID, r.Tier(), selectedScore)
 
 	return &SelectionResult{
 		SelectedModel: selectedModel.Model,
@@ -675,8 +674,7 @@ func (r *RLDrivenSelector) selectWithRouterR1(ctx context.Context, selCtx *Selec
 	logging.Infof("[RLDrivenSelector] Router-R1 selected %s (thinking: %s)",
 		selectedModel.Model, truncateString(response.Thinking, 100))
 
-	// Record metrics
-	RecordRLSelection(selectedModel.Model, selCtx.DecisionName, selCtx.UserID, 1.0)
+	RecordRLSelection(selectedModel.Model, selCtx.DecisionName, selCtx.UserID, r.Tier(), 1.0)
 
 	return &SelectionResult{
 		SelectedModel: selectedModel.Model,