gatus/main.go
2020-11-21 17:53:26 -05:00

98 lines
3.0 KiB
Go

package main
import (
"bytes"
"compress/gzip"
"log"
"net/http"
"os"
"strings"
"time"
"github.com/TwinProduction/gatus/config"
"github.com/TwinProduction/gatus/security"
"github.com/TwinProduction/gatus/watchdog"
"github.com/prometheus/client_golang/prometheus/promhttp"
)
const cacheTTL = 10 * time.Second
var (
cachedServiceResults []byte
cachedServiceResultsGzipped []byte
cachedServiceResultsTimestamp time.Time
)
func main() {
cfg := loadConfiguration()
resultsHandler := serviceResultsHandler
if cfg.Security != nil && cfg.Security.IsValid() {
resultsHandler = security.Handler(serviceResultsHandler, cfg.Security)
}
http.HandleFunc("/favicon.ico", favIconHandler) // favicon needs to be always served from the root
http.HandleFunc(cfg.Web.PrependWithContextRoot("/api/v1/results"), resultsHandler)
http.HandleFunc(cfg.Web.PrependWithContextRoot("/health"), healthHandler)
http.Handle(cfg.Web.ContextRoot, GzipHandler(http.StripPrefix(cfg.Web.ContextRoot, http.FileServer(http.Dir("./static")))))
if cfg.Metrics {
http.Handle(cfg.Web.PrependWithContextRoot("/metrics"), promhttp.Handler())
}
log.Printf("[main][main] Listening on %s%s\n", cfg.Web.SocketAddress(), cfg.Web.ContextRoot)
go watchdog.Monitor(cfg)
log.Fatal(http.ListenAndServe(cfg.Web.SocketAddress(), nil))
}
func loadConfiguration() *config.Config {
var err error
customConfigFile := os.Getenv("GATUS_CONFIG_FILE")
if len(customConfigFile) > 0 {
err = config.Load(customConfigFile)
} else {
err = config.LoadDefaultConfiguration()
}
if err != nil {
panic(err)
}
return config.Get()
}
func serviceResultsHandler(writer http.ResponseWriter, r *http.Request) {
if isExpired := cachedServiceResultsTimestamp.IsZero() || time.Now().Sub(cachedServiceResultsTimestamp) > cacheTTL; isExpired {
buffer := &bytes.Buffer{}
gzipWriter := gzip.NewWriter(buffer)
data, err := watchdog.GetJSONEncodedServiceResults()
if err != nil {
log.Printf("[main][serviceResultsHandler] 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()
cachedServiceResults = data
cachedServiceResultsGzipped = buffer.Bytes()
cachedServiceResultsTimestamp = time.Now()
}
var data []byte
if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
writer.Header().Set("Content-Encoding", "gzip")
data = cachedServiceResultsGzipped
} else {
data = cachedServiceResults
}
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")
}