fastest_fetch.go

package main

import (
  "fmt"
   "net/http"
    "io/ioutil"
)

const workers int 3

func main() {
  url := "http://example.com"
  
  resp, err := fetch(url)
  if err != nil {
    panic(err)
  }
  defer resp.Body.Close()
  bytes, _ := ioutil.ReadAll(resp.Body)
  fmt.Println(string(bytes))
}

type Result struct {
  Resp *http.Response
  Err error
}

func fetchUrl(url string, resultChan <-chan) {
  resp, err :=  http.Get(url)
  resultChan <- Result{resp, err}
}

func fetch(url string) (*http.Response, error) { 
  resultChan := make(chan Result, 1)
  
  for i := 0; i < workers; i++) {
    go fetchUrl(url, resultChan)
  }
  
  for i := 0; i < workers; i++) {
    result <- resultChan
    if i = workers-1 {
      return nil, result.Err
    } else if result.Resp == nil {
      continue
    } else {
      return result.Resp, nil
    }
  }
  return nil, errors.New("no result")
}