fix(telemetry)_: properly handle the size of the retryCache slice (#5510)

telemetry/client.go

@@ -140,7 +140,7 @@ func (c *Client) Start(ctx context.Context) {
 				if len(telemetryRequests) > 0 {
 					err := c.pushTelemetryRequest(telemetryRequests)
 					if err != nil {
-						if sendPeriod < 60 { //Stop the growing if the timer is > 60s to at least retry every minute
+						if sendPeriod < 60*time.Second { //Stop the growing if the timer is > 60s to at least retry every minute
 							sendPeriod = sendPeriod * 2
 						}
 					} else {
@@ -196,8 +196,8 @@ func (c *Client) processAndPushTelemetry(data interface{}) {
 
 // This is assuming to not run concurrently as we are not locking the `telemetryRetryCache`
 func (c *Client) pushTelemetryRequest(request []TelemetryRequest) error {
-	if len(c.telemetryRetryCache)+len(request) > MaxRetryCache { //Limit the size of the cache to not grow the slice indefinitely in case the Telemetry server is gone for longer time
-		removeNum := len(c.telemetryRetryCache) + len(request) - MaxRetryCache
+	if len(c.telemetryRetryCache) > MaxRetryCache { //Limit the size of the cache to not grow the slice indefinitely in case the Telemetry server is gone for longer time
+		removeNum := len(c.telemetryRetryCache) - MaxRetryCache
 		c.telemetryRetryCache = c.telemetryRetryCache[removeNum:]
 	}
 	c.telemetryRetryCache = append(c.telemetryRetryCache, request...)

telemetry/client_test.go

@@ -266,3 +266,32 @@ func TestRetryCache(t *testing.T) {
 
 	require.Equal(t, 0, len(client.telemetryRetryCache))
 }
+
+func TestRetryCacheCleanup(t *testing.T) {
+	client := createClient(t, "")
+	client.Start(context.Background())
+
+	for i := 0; i < 6000; i++ {
+		client.PushReceivedEnvelope(v2protocol.NewEnvelope(&pb.WakuMessage{
+			Payload:      []byte{1, 2, 3, 4, 5},
+			ContentTopic: testContentTopic,
+			Version:      proto.Uint32(0),
+			Timestamp:    proto.Int64(time.Now().Unix()),
+		}, 0, ""))
+	}
+
+	time.Sleep(110 * time.Millisecond)
+
+	require.Equal(t, 6000, len(client.telemetryRetryCache))
+
+	client.PushReceivedEnvelope(v2protocol.NewEnvelope(&pb.WakuMessage{
+		Payload:      []byte{1, 2, 3, 4, 5},
+		ContentTopic: testContentTopic,
+		Version:      proto.Uint32(0),
+		Timestamp:    proto.Int64(time.Now().Unix()),
+	}, 0, ""))
+
+	time.Sleep(210 * time.Millisecond)
+
+	require.Equal(t, 5001, len(client.telemetryRetryCache))
+}