Work on #62: Add uptime percentage + badges

controller/controller.go

@@ -0,0 +1,100 @@
+package controller
+
+import (
+	"bytes"
+	"compress/gzip"
+	"fmt"
+	"log"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/TwinProduction/gatus/config"
+	"github.com/TwinProduction/gatus/security"
+	"github.com/TwinProduction/gatus/watchdog"
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+const (
+	cacheTTL = 10 * time.Second
+)
+
+var (
+	cachedServiceStatuses          []byte
+	cachedServiceStatusesGzipped   []byte
+	cachedServiceStatusesTimestamp time.Time
+)
+
+// Handle creates the router and starts the server
+func Handle() {
+	cfg := config.Get()
+	router := CreateRouter(cfg)
+	server := &http.Server{
+		Addr:         fmt.Sprintf("%s:%d", cfg.Web.Address, cfg.Web.Port),
+		Handler:      router,
+		ReadTimeout:  15 * time.Second,
+		WriteTimeout: 15 * time.Second,
+		IdleTimeout:  15 * time.Second,
+	}
+	log.Printf("[controller][Handle] Listening on %s%s\n", cfg.Web.SocketAddress(), cfg.Web.ContextRoot)
+	log.Fatal(server.ListenAndServe())
+}
+
+// CreateRouter creates the router for the http server
+func CreateRouter(cfg *config.Config) *mux.Router {
+	router := mux.NewRouter()
+	statusesHandler := serviceStatusesHandler
+	if cfg.Security != nil && cfg.Security.IsValid() {
+		statusesHandler = security.Handler(serviceStatusesHandler, cfg.Security)
+	}
+	router.HandleFunc("/favicon.ico", favIconHandler).Methods("GET") // favicon needs to be always served from the root
+	router.HandleFunc(cfg.Web.PrependWithContextRoot("/api/v1/statuses"), statusesHandler).Methods("GET")
+	router.HandleFunc(cfg.Web.PrependWithContextRoot("/api/v1/badges/uptime/{duration}/{identifier}"), badgeHandler).Methods("GET")
+	router.HandleFunc(cfg.Web.PrependWithContextRoot("/health"), healthHandler).Methods("GET")
+	router.PathPrefix(cfg.Web.ContextRoot).Handler(GzipHandler(http.StripPrefix(cfg.Web.ContextRoot, http.FileServer(http.Dir("./static")))))
+	if cfg.Metrics {
+		router.Handle(cfg.Web.PrependWithContextRoot("/metrics"), promhttp.Handler()).Methods("GET")
+	}
+	return router
+}
+
+func serviceStatusesHandler(writer http.ResponseWriter, r *http.Request) {
+	if isExpired := cachedServiceStatusesTimestamp.IsZero() || time.Now().Sub(cachedServiceStatusesTimestamp) > cacheTTL; isExpired {
+		buffer := &bytes.Buffer{}
+		gzipWriter := gzip.NewWriter(buffer)
+		data, err := watchdog.GetJSONEncodedServiceStatuses()
+		if err != nil {
+			log.Printf("[main][serviceStatusesHandler] Unable to marshal object to JSON: %s", err.Error())
+			writer.WriteHeader(http.StatusInternalServerError)
+			_, _ = writer.Write([]byte("Unable to marshal object to JSON"))
+			return
+		}
+		gzipWriter.Write(data)
+		gzipWriter.Close()
+		cachedServiceStatuses = data
+		cachedServiceStatusesGzipped = buffer.Bytes()
+		cachedServiceStatusesTimestamp = time.Now()
+	}
+	var data []byte
+	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
+		writer.Header().Set("Content-Encoding", "gzip")
+		data = cachedServiceStatusesGzipped
+	} else {
+		data = cachedServiceStatuses
+	}
+	writer.Header().Add("Content-type", "application/json")
+	writer.WriteHeader(http.StatusOK)
+	_, _ = writer.Write(data)
+}
+
+func healthHandler(writer http.ResponseWriter, _ *http.Request) {
+	writer.Header().Add("Content-type", "application/json")
+	writer.WriteHeader(http.StatusOK)
+	_, _ = writer.Write([]byte("{\"status\":\"UP\"}"))
+}
+
+// favIconHandler handles requests for /favicon.ico
+func favIconHandler(writer http.ResponseWriter, request *http.Request) {
+	http.ServeFile(writer, request, "./static/favicon.ico")
+}