feat: add metric for skipped certs per client

fixes #34

Author: d-Rickyy-b

internal/metrics/prometheus.go

@@ -3,6 +3,7 @@ package metrics
 import (
 	"fmt"
 	"io"
+	"strings"
 	"sync"
 	"time"
 
@@ -46,6 +47,9 @@ func WritePrometheus(w io.Writer, exposeProcessMetrics bool) {
 		initCtLogMetrics()
 	}
 	ctLogMetricsInitMutex.Unlock()
+
+	getSkippedCertMetrics()
+
 	metrics.WritePrometheus(w, exposeProcessMetrics)
 }
 
@@ -82,3 +86,33 @@ func getCertCountForLog(operatorName, logname string) int64 {
 
 	return tempCertMetrics[operatorName][logname]
 }
+
+// getSkippedCertMetrics gets the number of skipped certificates for each client and creates metrics for it.
+// It also removes metrics for clients that are not connected anymore.
+func getSkippedCertMetrics() {
+	skippedCerts := web.ClientHandler.GetSkippedCerts()
+	for clientName := range skippedCerts {
+		// Get or register a new counter for each client
+		metricName := fmt.Sprintf("certstreamservergo_skipped_certs{client=\"%s\"}", clientName)
+		c := metrics.GetOrCreateCounter(metricName)
+		c.Set(skippedCerts[clientName])
+	}
+
+	// Remove all metrics that are not in the list of current client skipped cert metrics
+	// Get a list of current client skipped cert metrics
+	for _, metricName := range metrics.ListMetricNames() {
+		if !strings.HasPrefix(metricName, "certstreamservergo_skipped_certs") {
+			continue
+		}
+
+		clientName := strings.TrimPrefix(metricName, "certstreamservergo_skipped_certs{client=\"")
+		clientName = strings.TrimSuffix(clientName, "\"}")
+
+		// Check if the registered metric is in the list of current client skipped cert metrics
+		// If not, unregister the metric
+		_, exists := skippedCerts[clientName]
+		if !exists {
+			metrics.UnregisterMetric(metricName)
+		}
+	}
+}

internal/web/broadcastmanager.go

@@ -73,6 +73,18 @@ func (bm *BroadcastManager) clientCountByType(subType SubscriptionType) (count i
 	return count
 }
 
+func (bm *BroadcastManager) GetSkippedCerts() map[string]uint64 {
+	bm.clientLock.RLock()
+	defer bm.clientLock.RUnlock()
+
+	skippedCerts := make(map[string]uint64, len(bm.clients))
+	for _, c := range bm.clients {
+		skippedCerts[c.name] = c.skippedCerts
+	}
+
+	return skippedCerts
+}
+
 // broadcaster is run in a goroutine and handles the dispatching of entries to clients.
 func (bm *BroadcastManager) broadcaster() {
 	for {

internal/web/client.go

@@ -22,7 +22,7 @@ type client struct {
 	broadcastChan chan []byte
 	name          string
 	subType       SubscriptionType
-	skippedCerts  int64
+	skippedCerts  uint64
 }
 
 func newClient(conn *websocket.Conn, subType SubscriptionType, name string, certBufferSize int) *client {