Issue ipfs-cluster#449 API endpoint for Peer Monitor metrics

Opened new endpoint `GET /health/metrics/<name>` which would respond
with metrics of type <name>

License: MIT
Signed-off-by: Kishan Mohanbhai Sagathiya <kishansagathiya@gmail.com>

api/rest/restapi.go

@@ -385,6 +385,12 @@ func (api *API) routes() []route {
 			"/health/graph",
 			api.graphHandler,
 		},
+		{
+			"PeerMonitorLatestMetrics",
+			"GET",
+			"/health/metrics/{name}",
+			api.metricsHandler,
+		},
 	}
 }
 
@@ -506,6 +512,19 @@ func (api *API) graphHandler(w http.ResponseWriter, r *http.Request) {
 	api.sendResponse(w, autoStatus, err, graph)
 }
 
+func (api *API) metricsHandler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	name := vars["name"]
+
+	var metrics []types.Metric
+	err := api.rpcClient.Call("",
+		"Cluster",
+		"PeerMonitorLatestMetrics",
+		name,
+		&metrics)
+	sendResponse(w, err, metrics)
+}
+
 func (api *API) addHandler(w http.ResponseWriter, r *http.Request) {
 	reader, err := r.MultipartReader()
 	if err != nil {