内容简介:通过实例入门Golang
如果想学会一门新语言,不仅要多读文档,还要多看别人写的代码,更要强迫自己用新语言多写代码。我在学习 Golang 之前,读过好几本相关的书籍,不过总感觉没真正学会,于是我决定动手用 Golang 写一个能用的 工具 试试,因为 Golang 最大的优势就是 goroutine 和 channel,所以我觉得实现一个简版的 ab(Web 压力测试工具)应该是一个不错的选择,用 Golang 磕磕绊绊总算实现了预想的功能,能够计算 Requests per second 和 Time per request 的值,不过总感觉写出来的代码不够漂亮,于是我又找来 hey 的代码前后读了几遍,然后结合自己的理解临摹了一遍,感觉总算是入门了。
虽然 hey 的代码本身已经相当简洁,但是洋洋洒洒加起来也有五六百行代码,下面是我默写的版本,仅保留主体功能,总共就一两百行代码:
package main import ( "flag" "fmt" "log" "net/http" "os" "strings" "sync" "time" ) var usage = `Usage: %s [options] Options are: -n requests Number of requests to perform -c concurrency Number of multiple requests to make at a time -s timeout Seconds to max. wait for each response -m method Method name ` var ( requests int concurrency int timeout int method string url string ) func main() { flag.Usage = func() { fmt.Fprintf(os.Stderr, usage, os.Args[0]) } flag.IntVar(&requests, "n", 1000, "") flag.IntVar(&concurrency, "c", 100, "") flag.IntVar(&timeout, "s", 10, "") flag.StringVar(&method, "m", "GET", "") flag.Parse() if flag.NArg() != 1 { exit("Invalid url.") } method = strings.ToUpper(method) url = flag.Args()[0] if method != "GET" { exit("Invalid method.") } if requests < 1 || concurrency < 1 { exit("-n and -c cannot be smaller than 1.") } if requests < concurrency { exit("-n cannot be less than -c.") } w := Work{ Requests: requests, Concurrency: concurrency, Timeout: timeout, Method: method, Url: url, } w.Run() } func exit(msg string) { flag.Usage() fmt.Fprintln(os.Stderr, "\n[Error] "+msg) os.Exit(1) } type Work struct { Requests int Concurrency int Timeout int Method string Url string results chan *Result start time.Time end time.Time } type Result struct { Duration time.Duration } func (w *Work) Run() { w.results = make(chan *Result, w.Requests) w.start = time.Now() w.runWorkers() w.end = time.Now() close(w.results) w.print() } func (w *Work) runWorkers() { var wg sync.WaitGroup wg.Add(w.Concurrency) for i := 0; i < w.Concurrency; i++ { go func() { w.runWorker(w.Requests / w.Concurrency) defer wg.Done() }() } wg.Wait() } func (w *Work) runWorker(num int) { client := &http.Client{ Timeout: time.Duration(w.Timeout) * time.Second, } for i := 0; i < num; i++ { w.sendRequest(client) } } func (w *Work) sendRequest(client *http.Client) { req, err := http.NewRequest(w.Method, w.Url, nil) if err != nil { log.Fatal(err.Error()) } start := time.Now() client.Do(req) end := time.Now() w.results <- &Result{ Duration: end.Sub(start), } } func (w *Work) print() { sum := 0.0 num := float64(len(w.results)) for result := range w.results { sum += result.Duration.Seconds() } rps := int(num / w.end.Sub(w.start).Seconds()) tpr := sum / num * 1000 fmt.Printf("Requests per second:\t%d [#/sec]\n", rps) fmt.Printf("Time per request:\t%.3f [ms]\n", tpr) }
代码虽短,却涵盖了 Golang 常见的用法,搞懂它基本就算入门了。
以上就是本文的全部内容,希望本文的内容对大家的学习或者工作能带来一定的帮助,也希望大家多多支持 码农网
猜你喜欢:- 超级简单入门vuex 小实例
- 实例入门 Vue.js 单元测试
- 实例详解Spring MVC入门使用
- Spark 入门实战之最好的实例
- electron vue桌面应用入门实例
- 机器学习入门教程:启发式实例
本站部分资源来源于网络,本站转载出于传递更多信息之目的,版权归原作者或者来源机构所有,如转载稿涉及版权问题,请联系我们。
Introduction to Linear Optimization
Dimitris Bertsimas、John N. Tsitsiklis / Athena Scientific / 1997-02-01 / USD 89.00
"The true merit of this book, however, lies in its pedagogical qualities which are so impressive..." "Throughout the book, the authors make serious efforts to give geometric and intuitive explanations......一起来看看 《Introduction to Linear Optimization》 这本书的介绍吧!