//输入url,请求总次数，并发数，反馈平均耗时，95%耗时，失败请求数（失败请求不计入耗时）
func DoHttpPressureTest(url string ,testCount ,concurrentSize int)(averageSpan ,p95Span, failCount int){
	//runtime.GOMAXPROCS(runtime.NumCPU())
	runtime.GOMAXPROCS(concurrentSize)
	f:=DoHttpTest
	ready:=make(chan struct{})
	results:=make(chan TestResult,concurrentSize)
	var wg  sync.WaitGroup
	wg.Add(concurrentSize)
	pTestCount:=testCount/concurrentSize //每个线程执行的测试次数
	for t:=0;t<concurrentSize;t++{
		go func(){
			defer wg.Done()
			<-ready
			var failCount =0
			var timeSpan []int
			for i:=0;i<pTestCount;i++{
				if ok,span:=f(url);ok{
					timeSpan= append(timeSpan, span)
				}
			}
			//收集测试结果
			result:=TestResult{failCount:failCount,span:timeSpan}
			results<-result
		}()
	}
	time.Sleep(time.Second)
	close(ready)
	wg.Wait()
	close(results)
	//所有测试结果合并，统计
	var totalResul TestResult
	for result:=range results{
		totalResul.add(&result)
	}
	return totalResul.GetSpanStatistic()
}

func DoHttpTest(url string) (success bool,timespan int){
	begin:=GetCurrentTimestamp()
	if resp,err:=http.Get(url);err!=nil{
		return false,0
	}else{
		defer  resp.Body.Close()
		if  resp.StatusCode==200{
			end:=GetCurrentTimestamp()
			timespan=int(end-begin)
			return true,timespan
		}
		return false ,0
	}
}
//获取当前时间毫秒
func GetCurrentTimestamp() int64 {
	return time.Now().UnixNano() / 1e6
}

//测试结果记录
type TestResult struct {
	failCount  int
	span []int //所有成功请求耗时记录（ms ）
}
func(this *TestResult)add(newResult *TestResult){
	this.failCount=newResult.failCount
	this.span= append(this.span, newResult.span...)
}
//耗时统计：平均耗时，95%耗时，失败记录数
func (this *TestResult)GetSpanStatistic()(averageSpan ,p95Span ,failCount int){
	var successCount =len(this.span)
	sort.Ints(this.span)
	total:=0
	for _,s:=range this.span{
		fmt.Println(s)
		total+=s
	}
	averageSpan =total/ successCount
	p95Count :=successCount*95/100
	if p95Count>0{
		p95Total:=0
		for i:=0;i<p95Count;i++{
			p95Total+=this.span[i]
		}
		p95Span=p95Total/p95Count
	}
	return averageSpan,p95Span,this.failCount
}

func main(){
	doHttpTest4Baidu(100,10)
}
func doHttpTest4Baidu(testCount,concurrentSize int ){
	averageSpan,p95Sapan,failCount:=pressuretest.DoHttpPressureTest("http://www.baidu.com",testCount,concurrentSize)
	s:=fmt.Sprintf("并发数%d,平均响应时间%d ms,p95响应时间 %d ms,总请求数%d 总失败数%d",concurrentSize,averageSpan,p95Sapan,testCount,failCount)
	fmt.Println(s)
}