Add alerts endpoint to API client (#552)

Add alerts endpoint to API client. The alerts endpoint returns a list of all active alerts.

Signed-off-by: Roald Nefs <info@roaldnefs.com>

api/prometheus/v1/api.go

@@ -35,6 +35,7 @@ const (
 
 	apiPrefix = "/api/v1"
 
+	epAlerts          = apiPrefix + "/alerts"
 	epAlertManagers   = apiPrefix + "/alertmanagers"
 	epQuery           = apiPrefix + "/query"
 	epQueryRange      = apiPrefix + "/query_range"
@@ -115,6 +116,8 @@ type Range struct {
 
 // API provides bindings for Prometheus's v1 API.
 type API interface {
+	// Alerts returns a list of all active alerts.
+	Alerts(ctx context.Context) (AlertsResult, error)
 	// AlertManagers returns an overview of the current state of the Prometheus alert manager discovery.
 	AlertManagers(ctx context.Context) (AlertManagersResult, error)
 	// CleanTombstones removes the deleted data from disk and cleans up the existing tombstones.
@@ -142,6 +145,11 @@ type API interface {
 	Targets(ctx context.Context) (TargetsResult, error)
 }
 
+// AlertsResult contains the result from querying the alerts endpoint.
+type AlertsResult struct {
+	Alerts []Alert `json:"alerts"`
+}
+
 // AlertManagersResult contains the result from querying the alertmanagers endpoint.
 type AlertManagersResult struct {
 	Active  []AlertManager `json:"activeAlertManagers"`
@@ -402,6 +410,24 @@ type httpAPI struct {
 	client api.Client
 }
 
+func (h *httpAPI) Alerts(ctx context.Context) (AlertsResult, error) {
+	u := h.client.URL(epAlerts, nil)
+
+	req, err := http.NewRequest(http.MethodGet, u.String(), nil)
+	if err != nil {
+		return AlertsResult{}, err
+	}
+
+	_, body, err := h.client.Do(ctx, req)
+	if err != nil {
+		return AlertsResult{}, err
+	}
+
+	var res AlertsResult
+	err = json.Unmarshal(body, &res)
+	return res, err
+}
+
 func (h *httpAPI) AlertManagers(ctx context.Context) (AlertManagersResult, error) {
 	u := h.client.URL(epAlertManagers, nil)