Support sending grouped alerts on their own

main.go

@@ -49,7 +49,64 @@ type notification struct {
 	tags     string
 }
 
-func (rcv *receiver) newNotification(p *payload) *notification {
+func (rcv *receiver) singleAlertNotifications(p *payload) []*notification {
+	var notifications []*notification
+	for _, alert := range p.Alerts {
+		n := new(notification)
+
+		// create title
+		n.title = fmt.Sprintf("[%s]", strings.ToUpper(alert.Status))
+		if name, ok := alert.Labels["alertname"]; ok {
+			n.title = fmt.Sprintf("%s %s", n.title, name)
+		}
+
+		for _, value := range p.GroupLabels {
+			n.title = fmt.Sprintf("%s %s", n.title, value)
+		}
+
+		// create body
+		n.body = "Labels:\n"
+		for key, value := range alert.Labels {
+			n.body = fmt.Sprintf("%s%s = %s\n", n.body, key, value)
+		}
+
+		n.body += "\nAnnotations:\n"
+		for key, value := range alert.Annotations {
+			n.body = fmt.Sprintf("%s%s = %s\n", n.body, key, value)
+		}
+
+		var tags []string
+		for _, labelName := range rcv.cfg.labels.Order {
+			val, ok := alert.Labels[labelName]
+			if !ok {
+				continue
+			}
+
+			labelConfig, ok := rcv.cfg.labels.Label[fmt.Sprintf("%s:%s", labelName, val)]
+			if !ok {
+				continue
+			}
+
+			if n.priority == "" {
+				n.priority = labelConfig.Priority
+			}
+
+			for _, val := range labelConfig.Tags {
+				if !sliceContains(tags, val) {
+					tags = append(tags, val)
+				}
+			}
+		}
+
+		n.tags = strings.Join(tags, ",")
+
+		notifications = append(notifications, n)
+	}
+
+	return notifications
+}
+
+func (rcv *receiver) multiAlertNotification(p *payload) *notification {
 	n := new(notification)
 
 	// create title
@@ -175,10 +232,20 @@ func (rcv *receiver) handleWebhooks(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	notification := rcv.newNotification(&event)
-	err := rcv.publish(notification)
-	if err != nil {
-		rcv.logger.Error(err)
+	if rcv.cfg.alertMode == single {
+		notifications := rcv.singleAlertNotifications(&event)
+		for _, n := range notifications {
+			err := rcv.publish(n)
+			if err != nil {
+				rcv.logger.Errorf("Failed to publish notification: %v", err)
+			}
+		}
+	} else {
+		notification := rcv.multiAlertNotification(&event)
+		err := rcv.publish(notification)
+		if err != nil {
+			rcv.logger.Errorf("Failed to publish notification: %v", err)
+		}
 	}
 }