fix pipe closed issue, and a lot of other stuff

cmd/fluxd/main.go

@@ -1,15 +1,16 @@
 package main
 
 import (
-	"log"
 	"net/http"
 	_ "net/http/pprof"
 
 	"github.com/juls0730/flux/server"
+	"go.uber.org/zap"
 )
 
 func main() {
 	fluxServer := server.NewServer()
+	defer fluxServer.Stop()
 
 	http.HandleFunc("POST /deploy", fluxServer.DeployHandler)
 	http.HandleFunc("DELETE /deployments", fluxServer.DeleteAllDeploymentsHandler)
@@ -19,6 +20,9 @@ func main() {
 	http.HandleFunc("GET /apps", fluxServer.ListAppsHandler)
 	http.HandleFunc("GET /heartbeat", fluxServer.DaemonInfoHandler)
 
-	log.Printf("Fluxd started on http://127.0.0.1:5647\n")
-	log.Fatal(http.ListenAndServe(":5647", nil))
+	fluxServer.Logger.Info("Fluxd started on http://127.0.0.1:5647")
+	err := http.ListenAndServe(":5647", nil)
+	if err != nil {
+		fluxServer.Logger.Fatalf("Failed to start server: %v", zap.Error(err))
+	}
 }