Implement endpoint for UI routing tree representation

api.go

@@ -32,15 +32,19 @@ import (
 type API struct {
 	alerts   provider.Alerts
 	silences provider.Silences
+
+	route func() *UIRoute
+
 	// context is an indirection for testing.
 	context func(r *http.Request) context.Context
 }
 
-func RegisterAPI(r *route.Router, alerts provider.Alerts, silences provider.Silences) *API {
+func RegisterAPI(r *route.Router, alerts provider.Alerts, silences provider.Silences, rf func() *UIRoute) *API {
 	api := &API{
 		context:  route.Context,
 		alerts:   alerts,
 		silences: silences,
+		route:    rf,
 	}
 
 	// Register legacy forwarder for alert pushing.
@@ -49,6 +53,8 @@ func RegisterAPI(r *route.Router, alerts provider.Alerts, silences provider.Sile
 	// Register actual API.
 	r = r.WithPrefix("/v1")
 
+	r.Get("/routes", api.routes)
+
 	r.Get("/alerts", api.listAlerts)
 	r.Post("/alerts", api.addAlerts)
 
@@ -80,6 +86,33 @@ func (e *apiError) Error() string {
 	return fmt.Sprintf("%s: %s", e.typ, e.err)
 }
 
+func pruneUIRoute(r *UIRoute) {
+	for _, sr := range r.Routes {
+		pruneUIRoute(sr)
+	}
+
+	var nr []*UIRoute
+
+	for _, sr := range r.Routes {
+		if len(sr.Groups) == 0 && len(sr.Routes) == 0 {
+			continue
+		}
+		nr = append(nr, sr)
+	}
+
+	r.Routes = nr
+}
+
+func (api *API) routes(w http.ResponseWriter, req *http.Request) {
+	r := api.route()
+
+	if req.FormValue("pruneEmpty") == "true" {
+		pruneUIRoute(r)
+	}
+
+	respond(w, r)
+}
+
 func (api *API) listAlerts(w http.ResponseWriter, r *http.Request) {
 	alerts := api.alerts.GetPending()
 	defer alerts.Close()

dispatch.go

@@ -54,6 +54,41 @@ func (d *Dispatcher) Run() {
 	close(d.done)
 }
 
+type UIRoute struct {
+	RouteOpts *RouteOpts
+	Matchers  types.Matchers
+	Groups    []*UIGroup
+	Routes    []*UIRoute
+}
+
+type UIGroup struct {
+	Labels model.LabelSet
+	Alerts model.Alerts
+}
+
+func (d *Dispatcher) Populate(r *UIRoute) {
+	for _, sr := range r.Routes {
+		d.Populate(sr)
+	}
+
+	groups, ok := d.aggrGroups[r.RouteOpts]
+	if !ok {
+		return
+	}
+
+	for _, ag := range groups {
+		var as []*types.Alert
+		for _, a := range ag.alerts {
+			as = append(as, a)
+		}
+		g := &UIGroup{
+			Labels: ag.labels,
+			Alerts: types.Alerts(as...),
+		}
+		r.Groups = append(r.Groups, g)
+	}
+}
+
 func (d *Dispatcher) run(it provider.AlertIterator) {
 	cleanup := time.NewTicker(30 * time.Second)
 	defer cleanup.Stop()

main.go

@@ -128,7 +128,12 @@ func main() {
 	router := route.New()
 
 	RegisterWeb(router)
-	RegisterAPI(router.WithPrefix("/api"), alerts, silences)
+	RegisterAPI(router.WithPrefix("/api"), alerts, silences, func() *UIRoute {
+		uir := disp.route.UIRoute()
+		disp.Populate(uir)
+
+		return uir
+	})
 
 	go http.ListenAndServe(*listenAddress, router)
 

route.go

@@ -115,6 +115,20 @@ func NewRoutes(croutes []*config.Route, parent *Route) []*Route {
 	return res
 }
 
+func (r *Route) UIRoute() *UIRoute {
+	var subs []*UIRoute
+	for _, sr := range r.Routes {
+		subs = append(subs, sr.UIRoute())
+	}
+
+	uir := &UIRoute{
+		RouteOpts: &r.RouteOpts,
+		Matchers:  r.Matchers,
+		Routes:    subs,
+	}
+	return uir
+}
+
 // Match does a depth-first left-to-right search through the route tree
 // and returns the flattened configuration for the reached node.
 func (r *Route) Match(lset model.LabelSet) []*RouteOpts {