I want to run 2 goroutines parallel in App Engine, so that when the first goroutine finish its job, the handler doesn't need to wait the second goroutine - it stops the secend goroutine and returns the result to the client. Is this possible? I tried it with context.WithCancel(), but it didn't work (I use go1.6).
Here is my code:
package mytest
import (
"net/http"
"sync"
"time"
"golang.org/x/net/context"
"google.golang.org/appengine"
"google.golang.org/appengine/log"
"google.golang.org/appengine/urlfetch"
)
func init() {
http.HandleFunc("/test", handlerTest)
http.HandleFunc("/testwait10s", handlerTest10s)
http.HandleFunc("/testwait5s", handlerTest5s)
}
func handlerTest(w http.ResponseWriter, r *http.Request) {
c := appengine.NewContext(r)
ctx, _ := context.WithTimeout(c, 30*time.Second)
ctx1, ctx1Cancel := context.WithCancel(ctx)
ctx2, ctx2Cancel := context.WithCancel(ctx)
var wg sync.WaitGroup
wg.Add(2)
go func() {
defer wg.Done()
log.Infof(ctx1, "Go1 begin ...")
client1 := urlfetch.Client(ctx1)
_, err := client1.Get("http://APP_NAME.appspot.com/testwait5s")
if err != nil {
log.Errorf(ctx1, "Go1 failed: %v", err)
}
ctx2Cancel()
log.Infof(ctx1, "Go1 over ...")
}()
go func() {
defer wg.Done()
log.Infof(ctx2, "Go2 begin ...")
client2 := urlfetch.Client(ctx2)
_, err := client2.Get("http://APP_NAME.appspot.com/testwait10s")
if err != nil {
log.Errorf(ctx2, "Go2 failed %v", err)
}
ctx1Cancel()
log.Infof(ctx2, "Go2 over ...")
}()
wg.Wait()
log.Infof(ctx1, "Go1 and GO2 over")
}
func handlerTest10s(w http.ResponseWriter, r *http.Request) {
time.Sleep(10 * time.Second)
return
}
func handlerTest5s(w http.ResponseWriter, r *http.Request) {
time.Sleep(5 * time.Second)
return
}
Any ideas? Thanks!