haproxy.go

package main

import (
	"log"
	"os"
	"os/exec"
	"strconv"
	"text/template"
)

var tpl *template.Template = nil
var pid int = -1

func createConfigFile(backends []Backend, templateFile, outputFile string) error {
	cfgFile, _ := os.Create(outputFile)
	defer cfgFile.Close()

	if tpl == nil {
		var err error = nil
		tpl, err = template.ParseFiles(templateFile)
		if err != nil {
			return err
		}
	}

	return tpl.Execute(cfgFile, backends)
}

func reloadHAproxy(command, configFile string) error {
	var cmd *exec.Cmd = nil
	if pid == -1 {
		log.Println("Start HAproxy")
		cmd = exec.Command(command, "-f", configFile)
		go cmd.Wait()
	} else {
		log.Println("Restart HAproxy")
		cmd = exec.Command(command, "-f", configFile, "-sf", strconv.Itoa(pid))
	}

	err := cmd.Start()
	if err == nil {
		pid = cmd.Process.Pid
		log.Println("New pid: ", pid)
	}
	return err
}