check sync status of an IOTA full node

iota_sync.go

//USAGE: go run iota_sync.go http://IP:PORT

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
	"time"
)

func main() {
	var lastIndex int64
	for {
		info, err := getNodeInfo(os.Args[1])
		if err != nil {
			fmt.Printf("error: %s\n", err)
		} else if info != nil {
			newIndex := info.SubtanlgeIndex
			percent := 100 * float64(info.SubtanlgeIndex) / float64(info.LatestIndex)
			if lastIndex != newIndex {
				lastIndex = newIndex
				fmt.Printf("synced: %f%%\ttips: %d\tindex: %d/%d\n", percent, info.Tips, info.SubtanlgeIndex, info.LatestIndex)
			}
		}
		time.Sleep(time.Second * 60)
	}
}

func try(err error) {
	if err != nil {
		panic(err)
	}
}

func getNodeInfo(url string) (result *nodeInfo, rekt error) {
	defer func() {
		rekt := recover()
		if rekt != nil {
			return
		}
		return
	}()

	client := http.Client{}
	req, err := http.NewRequest("POST", url, bytes.NewBuffer([]byte("{\"command\": \"getNodeInfo\"}")))
	try(err)
	req.Header.Add("X-IOTA-API-VERSION", "1.4")
	req.Header.Add("Content-Type", "application/json")
	res, err := client.Do(req)
	try(err)
  
	data, err := ioutil.ReadAll(res.Body)
	try(err)
	var info nodeInfo
	err = json.Unmarshal(data, &info)
	try(err)
	result = &info
	return
}

type nodeInfo struct {
	Name           string `json:"appName"`
	AppVersion     string `json:"appVersion"`
	Neighbors      int    `json:"neighbors"`
	SubtanlgeIndex int64  `json:"latestSolidSubtangleMilestoneIndex"`
	LatestIndex    int64  `json:"latestMilestoneIndex"`
	Tips           int64  `json:"tips"`
}