import "github.com/sparrc/go-ping"
import "time"
func (p *Ping) doPing(timeout time.Duration, count int, ip string) (err error) {
 pinger, cmdErr := ping.NewPinger(ip)
 if cmdErr != nil {
  glog.Error("Failed to ping " + p.ipAddr)
  err = cmdErr
  return
 }
 pinger.Count = count
 pinger.Interval = time.Second
 pinger.Timeout = timeout
 // true的话，代表是标准的icmp包，false代表可以丢包类似udp
 pinger.SetPrivileged(false)
 // 执行
 pinger.Run() 
 // 获取ping后的返回信息
 stats := pinger.Statistics() 
 //延迟
 latency = float64(stats.AvgRtt) 
 // 标准的往返总时间 
 jitter = float64(stats.StdDevRtt) 
 //丢包率 
 packetLoss = stats.PacketLoss 
 return
}

package main
import (
 "github.com/reiver/go-telnet"
)
func doTelnet(ip string, port int) {
 var caller telnet.Caller = telnet.StandardCaller
 address := ip + ":"+ strconv.Itoa(port)
 // DialToAndCall 检查连通性并且调用
 telnet.DialToAndCall(address, caller)
 }
}

import "net"
func doTelnet(ip string, ports []string) map[string]string {
 // 检查 emqx 1883, 8083, 8080, 18083 端口
 results := make(map[string]string)
 for _, port := range ports {
 address := net.JoinHostPort(ip, port)
 // 3 秒超时
 conn, err := net.DialTimeout("tcp", address, 3*time.Second)
 if err != nil {
 results[port] = "failed"
 } else {
 if conn != nil {
 results[port] = "success"
 _ = conn.Close()
 } else {
 results[port] = "failed"
 }
 }
 }
 return results
}

while read ip
do
 {
 doPing(ip)
 } &
done < ip.txt

import (
 "context"
 "fmt"
 "log"
 "time"
 "sync"
 "golang.org/x/time/rate"
)
func Limit(ips []string)([]string, []string, error) {
 //第一个参数是每秒钟最大的并发数，第二个参数是桶的容量，第一次的时候每秒可执行的数量就是桶的容量，建议这两个值都写成一样的
 r := rate.NewLimiter(10, 10)
 ctx := context.Background()
 
 wg := sync.WaitGroup{}
 wg.Add(len(ips))
 
 lock := sync.Mutex{}
 var success []string
 var fail []string
 
 defer wg.Done()
 for _,ip:=range ips{
 //每次消耗2个，放入一个，消耗完了还会放进去，如果初始是5个，所以这段代码再执行到第4次的时候筒里面就空了，如果当前不够取两个了，本次就不取，再放一个进去，然后返回false
 err := r.WaitN(ctx, 2)
 if err != nil {
  log.Fatal(err)
 }
 go func(ip string) {
 defer func() {
 wg.Done()
 }()
 err := doPing(time.Second, 2, ip)
 lock.Lock()
 defer lock.Unlock()
 if err != nil {
 fail = append(fail, ip)
 return
 } else {
 success = append(success, ip)
 }
 }(ip)
 }
 // wait等待所有go协程结束
 wg.wait()
 return success,fail,nil
}
func main() {
 ips := [2]string{"192.168.1.1","192.168.1.2"}
 success,fail,err := Limit(ips)
 if err != nil {
 fmt.Printf("ping error")
 }
}

func main() {
 go print() // 启动一个goroutine
 print()
}
func print() {
fmt.Println("*******************")
}

func main() {
 var channel chan string = make(chan string)
 go func(message string) {
 channel<- message // 存消息
 }("Ping!")
 fmt.Println(<-messages) // 取消息
}

channel := make(chan int, 3)
channel <- 1
channel <- 2
channel <- 3
// 显式关闭信道
close(channel)
for v := range channel {
 fmt.Println(v)
 // 如果现有数据量为0，跳出循环，与显式关闭隧道效果一样，选一个即可
 if len(ch) <= 0 { 
 break
 }
}

// 创建一个计时信道
timeout := time.After(1 * time.Second) 
// 监听3个信道的数据
select {
 case v1 := <- c1: fmt.Printf("received %d from c1", v1)
 case v2 := <- c2: fmt.Printf("received %d from c2", v2)
 case v3 := <- c3: fmt.Printf("received %d from c3", v3)
 case <- timeout: 
 is_timeout = true // 超时
 break
 }
}