feat(api): summarize alertmanager counts in group API

internal/models/alertgroup.go

@@ -33,12 +33,13 @@ func (a AlertList) Less(i, j int) bool {
 // There is a hash computed from all alerts, it's used by UI to quickly tell
 // if there was any change in a group and it needs to refresh it
 type AlertGroup struct {
-	Receiver   string            `json:"receiver"`
-	Labels     map[string]string `json:"labels"`
-	Alerts     AlertList         `json:"alerts"`
-	ID         string            `json:"id"`
-	Hash       string            `json:"hash"`
-	StateCount map[string]int    `json:"stateCount"`
+	Receiver          string            `json:"receiver"`
+	Labels            map[string]string `json:"labels"`
+	Alerts            AlertList         `json:"alerts"`
+	ID                string            `json:"id"`
+	Hash              string            `json:"hash"`
+	AlertmanagerCount map[string]int    `json:"alertmanagerCount"`
+	StateCount        map[string]int    `json:"stateCount"`
 }
 
 // LabelsFingerprint is a checksum of this AlertGroup labels and the receiver

views.go

@@ -84,11 +84,12 @@ func alerts(c *gin.Context) {
 	var matches int
 	for _, ag := range dedupedAlerts {
 		agCopy := models.AlertGroup{
-			ID:         ag.ID,
-			Receiver:   ag.Receiver,
-			Labels:     ag.Labels,
-			Alerts:     []models.Alert{},
-			StateCount: map[string]int{},
+			ID:                ag.ID,
+			Receiver:          ag.Receiver,
+			Labels:            ag.Labels,
+			Alerts:            []models.Alert{},
+			AlertmanagerCount: map[string]int{},
+			StateCount:        map[string]int{},
 		}
 		for _, s := range models.AlertStateList {
 			agCopy.StateCount[s] = 0
@@ -127,6 +128,14 @@ func alerts(c *gin.Context) {
 
 				agCopy.StateCount[alert.State]++
 
+				for _, am := range alert.Alertmanager {
+					if _, found := agCopy.AlertmanagerCount[am.Name]; !found {
+						agCopy.AlertmanagerCount[am.Name] = 1
+					} else {
+						agCopy.AlertmanagerCount[am.Name]++
+					}
+				}
+
 				for key, value := range alert.Labels {
 					if keyMap, foundKey := dedupedColors[key]; foundKey {
 						if color, foundColor := keyMap[value]; foundColor {