Code cleanup of routes config loader and API server (#424)

server/api_server.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"encoding/json"
 	"expvar"
 	"net/http"
 
@@ -9,11 +10,12 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-var apiRoutes = mux.NewRouter()
-
 func StartApiServer(apiBinding string) {
 	logrus.WithField("binding", apiBinding).Info("Serving API requests")
 
+	var apiRoutes = mux.NewRouter()
+	registerApiRoutes(apiRoutes)
+
 	apiRoutes.Path("/vars").Handler(expvar.Handler())
 
 	apiRoutes.Path("/metrics").Handler(promhttp.Handler())
@@ -23,3 +25,84 @@ func StartApiServer(apiBinding string) {
 			http.ListenAndServe(apiBinding, apiRoutes)).Error("API server failed")
 	}()
 }
+
+func registerApiRoutes(apiRoutes *mux.Router) {
+	apiRoutes.Path("/routes").Methods("GET").
+		HandlerFunc(routesListHandler)
+	apiRoutes.Path("/routes").Methods("POST").
+		HandlerFunc(routesCreateHandler)
+	apiRoutes.Path("/defaultRoute").Methods("POST").
+		HandlerFunc(routesSetDefault)
+	apiRoutes.Path("/routes/{serverAddress}").Methods("DELETE").HandlerFunc(routesDeleteHandler)
+}
+
+func routesListHandler(writer http.ResponseWriter, _ *http.Request) {
+	mappings := Routes.GetMappings()
+	bytes, err := json.Marshal(mappings)
+	if err != nil {
+		logrus.WithError(err).Error("Failed to marshal mappings")
+		writer.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	writer.Header().Set("Content-Type", "application/json")
+	_, err = writer.Write(bytes)
+	if err != nil {
+		logrus.WithError(err).Error("Failed to write response")
+	}
+}
+
+func routesDeleteHandler(writer http.ResponseWriter, request *http.Request) {
+	serverAddress := mux.Vars(request)["serverAddress"]
+	if serverAddress != "" {
+		if Routes.DeleteMapping(serverAddress) {
+			writer.WriteHeader(http.StatusOK)
+		} else {
+			writer.WriteHeader(http.StatusNotFound)
+		}
+		RoutesConfigLoader.SaveRoutes()
+	}
+}
+
+func routesCreateHandler(writer http.ResponseWriter, request *http.Request) {
+	var definition = struct {
+		ServerAddress string
+		Backend       string
+	}{}
+
+	//goland:noinspection GoUnhandledErrorResult
+	defer request.Body.Close()
+
+	decoder := json.NewDecoder(request.Body)
+	err := decoder.Decode(&definition)
+	if err != nil {
+		logrus.WithError(err).Error("Unable to get request body")
+		writer.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	Routes.CreateMapping(definition.ServerAddress, definition.Backend, EmptyScalerFunc, EmptyScalerFunc)
+	RoutesConfigLoader.SaveRoutes()
+	writer.WriteHeader(http.StatusCreated)
+}
+
+func routesSetDefault(writer http.ResponseWriter, request *http.Request) {
+	var body = struct {
+		Backend string
+	}{}
+
+	//goland:noinspection GoUnhandledErrorResult
+	defer request.Body.Close()
+
+	decoder := json.NewDecoder(request.Body)
+	err := decoder.Decode(&body)
+	if err != nil {
+		logrus.WithError(err).Error("Unable to parse request")
+		writer.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	Routes.SetDefaultRoute(body.Backend)
+	RoutesConfigLoader.SaveRoutes()
+	writer.WriteHeader(http.StatusOK)
+}