gatus/controller/controller.go
2021-03-05 00:40:11 -05:00

172 lines
5.9 KiB
Go

package controller
import (
"bytes"
"compress/gzip"
"context"
"encoding/json"
"fmt"
"log"
"net/http"
"os"
"strings"
"time"
"github.com/TwinProduction/gatus/config"
"github.com/TwinProduction/gatus/security"
"github.com/TwinProduction/gatus/storage"
"github.com/TwinProduction/gocache"
"github.com/TwinProduction/health"
"github.com/gorilla/mux"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
const (
cacheTTL = 10 * time.Second
)
var (
cache = gocache.NewCache().WithMaxSize(100).WithEvictionPolicy(gocache.FirstInFirstOut)
// staticFolder is the path to the location of the static folder from the root path of the project
// The only reason this is exposed is to allow running tests from a different path than the root path of the project
staticFolder = "./web/static"
// server is the http.Server created by Handle.
// The only reason it exists is for testing purposes.
server *http.Server
)
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()
var router http.Handler = CreateRouter(cfg)
if os.Getenv("ENVIRONMENT") == "dev" {
router = developmentCorsHandler(router)
}
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.Println("[controller][Handle] Listening on " + cfg.Web.SocketAddress())
if os.Getenv("ROUTER_TEST") == "true" {
return
}
log.Println("[controller][Handle]", server.ListenAndServe())
}
// Shutdown stops the server
func Shutdown() {
if server != nil {
_ = server.Shutdown(context.TODO())
server = nil
}
}
// CreateRouter creates the router for the http server
func CreateRouter(cfg *config.Config) *mux.Router {
router := mux.NewRouter()
if cfg.Metrics {
router.Handle("/metrics", promhttp.Handler()).Methods("GET")
}
router.Handle("/health", health.Handler().WithJSON(true)).Methods("GET")
router.HandleFunc("/favicon.ico", favIconHandler).Methods("GET")
router.HandleFunc("/api/v1/statuses", secureIfNecessary(cfg, serviceStatusesHandler)).Methods("GET") // No GzipHandler for this one, because we cache the content
router.HandleFunc("/api/v1/statuses/{key}", secureIfNecessary(cfg, GzipHandlerFunc(serviceStatusHandler))).Methods("GET")
router.HandleFunc("/api/v1/badges/uptime/{duration}/{identifier}", badgeHandler).Methods("GET")
// SPA
router.HandleFunc("/services/{service}", spaHandler).Methods("GET")
// Everything else falls back on static content
router.PathPrefix("/").Handler(GzipHandler(http.FileServer(http.Dir(staticFolder))))
return router
}
func secureIfNecessary(cfg *config.Config, handler http.HandlerFunc) http.HandlerFunc {
if cfg.Security != nil && cfg.Security.IsValid() {
return security.Handler(handler, cfg.Security)
}
return handler
}
// serviceStatusesHandler handles requests to retrieve all service statuses
// Due to the size of the response, this function leverages a cache.
// Must not be wrapped by GzipHandler
func serviceStatusesHandler(writer http.ResponseWriter, r *http.Request) {
page, pageSize := extractPageAndPageSizeFromRequest(r)
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(fmt.Sprintf("service-status-%d-%d-gzipped", page, pageSize))
} else {
value, exists = cache.Get(fmt.Sprintf("service-status-%d-%d", page, pageSize))
}
var data []byte
if !exists {
var err error
buffer := &bytes.Buffer{}
gzipWriter := gzip.NewWriter(buffer)
data, err = json.Marshal(storage.Get().GetAllServiceStatusesWithResultPagination(page, pageSize))
if err != nil {
log.Printf("[controller][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(fmt.Sprintf("service-status-%d-%d", page, pageSize), data, cacheTTL)
cache.SetWithTTL(fmt.Sprintf("service-status-%d-%d-gzipped", page, pageSize), gzippedData, cacheTTL)
if gzipped {
data = gzippedData
}
} else {
data = value.([]byte)
}
writer.Header().Add("Content-Type", "application/json")
writer.WriteHeader(http.StatusOK)
_, _ = writer.Write(data)
}
// serviceStatusHandler retrieves a single ServiceStatus by group name and service name
func serviceStatusHandler(writer http.ResponseWriter, r *http.Request) {
page, pageSize := extractPageAndPageSizeFromRequest(r)
vars := mux.Vars(r)
serviceStatus := storage.Get().GetServiceStatusByKey(vars["key"])
if serviceStatus == nil {
log.Printf("[controller][serviceStatusHandler] Service with key=%s not found", vars["key"])
writer.WriteHeader(http.StatusNotFound)
_, _ = writer.Write([]byte("not found"))
return
}
data := map[string]interface{}{
"serviceStatus": serviceStatus.WithResultPagination(page, pageSize),
// The following fields, while present on core.ServiceStatus, are annotated to remain hidden so that we can
// expose only the necessary data on /api/v1/statuses.
// Since the /api/v1/statuses/{key} endpoint does need this data, however, we explicitly expose it here
"events": serviceStatus.Events,
"uptime": serviceStatus.Uptime,
}
output, err := json.Marshal(data)
if err != nil {
log.Printf("[controller][serviceStatusHandler] Unable to marshal object to JSON: %s", err.Error())
writer.WriteHeader(http.StatusInternalServerError)
_, _ = writer.Write([]byte("unable to marshal object to JSON"))
return
}
writer.Header().Add("Content-Type", "application/json")
writer.WriteHeader(http.StatusOK)
_, _ = writer.Write(output)
}