gatus/controller/controller.go

115 lines
3.6 KiB
Go

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/TwinProduction/gocache"
"github.com/gorilla/mux"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
const (
cacheTTL = 10 * time.Second
)
var (
cache = gocache.NewCache().WithMaxSize(100).WithEvictionPolicy(gocache.LeastRecentlyUsed)
)
func init() {
if err := cache.StartJanitor(); err != nil {
log.Fatal("[controller][init] Failed to start cache janitor:", err.Error())
}
}
// 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) {
gzipped := strings.Contains(r.Header.Get("Accept-Encoding"), "gzip")
var exists bool
var value interface{}
if gzipped {
writer.Header().Set("Content-Encoding", "gzip")
value, exists = cache.Get("service-status-gzipped")
} else {
value, exists = cache.Get("service-status")
}
var data []byte
if !exists {
var err error
buffer := &bytes.Buffer{}
gzipWriter := gzip.NewWriter(buffer)
data, err = watchdog.GetServiceStatusesAsJSON()
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()
gzippedData := buffer.Bytes()
cache.SetWithTTL("service-status", data, cacheTTL)
cache.SetWithTTL("service-status-gzipped", gzippedData, cacheTTL)
if gzipped {
data = gzippedData
}
} else {
data = value.([]byte)
}
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")
}