main.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net"
	"net/http"
	"os"

	"go.uber.org/zap"

	"golang.org/x/net/netutil"
)

func main() {
	testConfig := flag.Bool("t", false, "test the configuration file and exit")
	configFile := flag.String("c", DefaultConfigPath, "configuration file to use instead of the default")
	flag.Parse()

	// Read server config
	config, err := LoadConfig(*configFile)
	if err != nil {
		fmt.Fprintln(os.Stderr, "configuration file is invalid:", err)
		os.Exit(1)
	}

	if *testConfig {
		fmt.Fprintln(os.Stderr, "configuration file test passed successfully")
		os.Exit(0)
	}

	// Basic server setup
	srv := NewServerWithConfig(config)
	defer srv.Close()

	// Limit simultaneous requests.
	listener, err := net.Listen("tcp", srv.config.Addr)
	if err != nil {
		panic(err)
	}
	defer listener.Close()

	if srv.config.MaxConns > 0 {
		listener = netutil.LimitListener(listener, srv.config.MaxConns)
	}

	srv.logger.Debug("starting web server",
		zap.Int("limit", srv.config.MaxConns),
		zap.String("addr", srv.config.Addr),
	)

	// Try to send notification to systemd.
	// It fails when server has started manually, so don't panic on error.
	if err := SdNotify("READY=1"); err != nil {
		log.Printf("Failed to notify systemd: %s", err)
	}

	// Run web server
	err = http.Serve(listener, nil)
	log.Fatal(err)
}