fix: register MaxPodHitCount metric in Collectors()

pkg/kvcache/metrics/collector.go

@@ -78,7 +78,7 @@ var (
 func Collectors() []prometheus.Collector {
 	return []prometheus.Collector{
 		Admissions, Evictions,
-		LookupRequests, LookupHits, LookupLatency,
+		LookupRequests, LookupHits, LookupLatency, MaxPodHitCount,
 		RenderChatTemplateLatency, TokenizationLatency, TokenizedTokensCount,
 	}
 }
@@ -145,11 +145,19 @@ func logMetrics(ctx context.Context) {
 		latencyAvg = latencySum / float64(latencyCount)
 	}
 
+	var maxPodHitMetric dto.Metric
+	err = MaxPodHitCount.Write(&maxPodHitMetric)
+	if err != nil {
+		return
+	}
+	maxPodHitCount := maxPodHitMetric.GetCounter().GetValue()
+
 	log.FromContext(ctx).WithName("metrics").Info("metrics beat",
 		"admissions", admissions,
 		"evictions", evictions,
 		"lookups", lookups,
 		"hits", hits,
+		"max_pod_hit_count", maxPodHitCount,
 		"latency_count", latencyCount,
 		"latency_sum", latencySum,
 		"latency_avg", latencyAvg,

pkg/kvcache/metrics/collector_test.go

@@ -23,9 +23,45 @@ import (
 	"testing"
 
 	"github.com/go-logr/logr"
+	"github.com/prometheus/client_golang/prometheus"
 	"sigs.k8s.io/controller-runtime/pkg/log"
 )
 
+func TestCollectorsIncludesAllMetrics(t *testing.T) {
+	collectors := Collectors()
+
+	// Build a set of collector pointers for lookup and ensure Collectors()
+	// does not return duplicates, which would panic during MustRegister.
+	collectorSet := make(map[prometheus.Collector]bool, len(collectors))
+	for _, c := range collectors {
+		if collectorSet[c] {
+			t.Fatalf("Collectors() contains a duplicate collector: %T", c)
+		}
+		collectorSet[c] = true
+	}
+
+	expected := []struct {
+		name      string
+		collector prometheus.Collector
+	}{
+		{"Admissions", Admissions},
+		{"Evictions", Evictions},
+		{"LookupRequests", LookupRequests},
+		{"LookupHits", LookupHits},
+		{"LookupLatency", LookupLatency},
+		{"MaxPodHitCount", MaxPodHitCount},
+		{"RenderChatTemplateLatency", RenderChatTemplateLatency},
+		{"TokenizationLatency", TokenizationLatency},
+		{"TokenizedTokensCount", TokenizedTokensCount},
+	}
+
+	for _, e := range expected {
+		if !collectorSet[e.collector] {
+			t.Errorf("Collectors() is missing %s", e.name)
+		}
+	}
+}
+
 func TestLogMetrics(t *testing.T) {
 	// Set up a buffer to capture log output
 	var buf bytes.Buffer
@@ -94,4 +130,17 @@ func TestLogMetrics(t *testing.T) {
 			}
 		}
 	})
+
+	t.Run("max_pod_hit_count_logged", func(t *testing.T) {
+		buf.Reset()
+
+		MaxPodHitCount.Add(42)
+
+		logMetrics(ctx)
+
+		output := buf.String()
+		if !strings.Contains(output, "max_pod_hit_count=42") {
+			t.Errorf("Expected 'max_pod_hit_count=42' in log output, but it was not found. Full output: %s", output)
+		}
+	})
 }