How to realize Goroutine Pool through Channel

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Recently, Go is used to import data from Excel to the server using http requests.

However, a problem was found that after reading from the file, the new Goroutine will be added without restriction.

As a result, all the cards were stuck in the initialization request, so they got stuck.

Problem simulation

Simulation code

Func main () {pool: = sync.WaitGroup {} for I: = 0500 Resp + {pool.Add (1) go func (I int) {resp, err: = http.Get ("http://ip.3322.org") if err! = nil {fmt.Println (I, err)} else {defer resp.Body.Close () result) = ioutil.ReadAll (resp.Body) fmt.Println (I, string (result))} pool.Done ()} (I)} pool.Wait ()}

There is no problem in the case of a small number, but in the case of a large number, it will be found that the program has been stuck for a period of time and no request has been made.

Problem solving

In fact, we can see that it is because too many HTTP requests are initiated at the same time that the system does not send dead data.

Thinking that I submit requests with Thread in Java, I consider whether the number of Goroutine can be limited.

Sure enough, using the powerful Baidu has found the cooperation pool that the boss has already written.

The code is as follows. I added comments.

Package gopoolimport ("sync") / / Pool Goroutine Pooltype Pool struct {queue chan int wg * sync.WaitGroup} / / New create a new protocol pool func New (size int) * Pool {if size