问http.client通过RoundTrip超过限速并产生致命恐慌

EN

package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
    "sync"
    "time"

    "golang.org/x/time/rate"
)

var client http.Client

// ThrottledTransport Rate Limited HTTP Client
type ThrottledTransport struct {
    roundTripperWrap http.RoundTripper
    ratelimiter      *rate.Limiter
}

func (c *ThrottledTransport) RoundTrip(r *http.Request) (*http.Response, error) {
    err := c.ratelimiter.Wait(r.Context()) // This is a blocking call. Honors the rate limit
    if err != nil {
        return nil, err
    }
    return c.roundTripperWrap.RoundTrip(r)
}

// NewRateLimitedTransport wraps transportWrap with a rate limitter
func NewRateLimitedTransport(transportWrap http.RoundTripper) http.RoundTripper {
    return &ThrottledTransport{
        roundTripperWrap: transportWrap,
        //ratelimiter:      rate.NewLimiter(rate.Every(limitPeriod), requestCount),
        ratelimiter: rate.NewLimiter(10, 10),
    }
}

func main() {
    concurrency := 20
    var ch = make(chan int, concurrency)
    var wg sync.WaitGroup

    wg.Add(concurrency)
    for i := 0; i < concurrency; i++ {
        go func() {
            for {
                a, ok := <-ch
                if !ok { // if there is nothing to do and the channel has been closed then end the goroutine
                    wg.Done()
                    return
                }
                resp, err := client.Get("https://api.guildwars2.com/v2/items/12452")
                if err != nil {
                    fmt.Println(err)
                }
                body, err := ioutil.ReadAll(resp.Body)
                if err != nil {
                    fmt.Println(err)
                }
                fmt.Println(a, ":", string(body[4:29]))
            }
        }()
    }
    client = http.Client{}
    client.Timeout = time.Second * 10

    // Rate limits 600 requests per 60 seconds via RoundTripper
    transport := NewRateLimitedTransport(http.DefaultTransport)
    client.Transport = transport

    for i := 0; i < 64000; i++ {
        ch <- i // add i to the queue
    }

    wg.Wait()
    fmt.Println("done")
}