How to stop a goroutine when an error occurs

Question

When one occur error, how to stop another?

I must use res1 and res2，in production res1, res2 are not same static type.

package main

import (
    "fmt"
    "net/http"
    "sync"
)

func main() {
    wg := &sync.WaitGroup{}
    wg.Add(2)

    var res1, res2 *http.Response
    var err1, err2 error

    go func() {
        defer wg.Done()
        res1, err1 = http.Get("http://127.0.0.1:8899")
        if err1 != nil {
            panic(err1)
        }
    }()
    go func() {
        defer wg.Done()
        res2, err2 = http.Get("http://127.0.0.1:8898")
        if err2 != nil {
            panic(err2)
        }
    }()
    wg.Wait()

    fmt.Println(res1, res2)
}

Answer 1

A common context should be able to cancel all waiting requests. Something like this:

ctx, cancel:=context.WithCancel(context.Background())
defer cancel()
cli:=http.Client{}
go func() {
   req:=http.NewRequestWithContext(ctx,http.MethodGet,url,nil)
   respose, err:=cli.Do(req)
   if err != nil {
     cancel()
     return
   }
}()

You should use the same ctx for all http requests, and when one fails, cancel it. Once the context is canceled, all other http requests should cancel as well.