custom application metrics

Author: wolfy-j

service/metrics/rpc.go

@@ -70,3 +70,29 @@ func (rpc *rpcServer) Add(m *Metric, ok *bool) error {
 	*ok = true
 	return nil
 }
+
+// Set the metric value (only for gaude).
+func (rpc *rpcServer) Set(m *Metric, ok *bool) error {
+	c := rpc.svc.Collector(m.Name)
+	if c == nil {
+		return fmt.Errorf("undefined collector `%s`", m.Name)
+	}
+
+	switch c.(type) {
+	case prometheus.Gauge:
+		c.(prometheus.Gauge).Set(m.Value)
+
+	case *prometheus.GaugeVec:
+		if len(m.Labels) == 0 {
+			return fmt.Errorf("required labels for collector `%s`", m.Name)
+		}
+
+		c.(*prometheus.GaugeVec).WithLabelValues(m.Labels...).Set(m.Value)
+
+	default:
+		return fmt.Errorf("collector `%s` is not `gauge` type", m.Name)
+	}
+
+	*ok = true
+	return nil
+}