Process parallel http request in GO

[Fersca]

Hi,

I was playing with the HTTP package. I wanted to process request in
parallel as I do in java. But I couldn't.

I created a simple web server, put a sleep in the middle and realized
that go process one request per time, so if I did a refresh on my
browser, the process of the first request has to finish until the
second request start processing, here is the code:

func main(){

//Process the http commands
fmt.Printf("Starting http Server ... ")
http.Handle("/", http.HandlerFunc(sayHello))
err := http.ListenAndServe("0.0.0.0:8080", nil)
if err != nil {
fmt.Printf("ListenAndServe Error",err)
}
}

func sayHello(c http.ResponseWriter, req *http.Request) {
fmt.Printf("New Request\n")
processRequest(c, req)
}

func processRequest(w http.ResponseWriter, req *http.Request){
time.Sleep(time.Second*3)
w.Write([]byte("Go Say’s Hello(Via http)"))
fmt.Println("End")
}

As I wanted to process both request in parallel I added the "go"
command before "processRequest(c, req)" in "sayHello" function. But...
it doesn't work.... I don't know why. I know that both request are
processed because I see the printed line at the console but the
browser keep waiting for information..... and don't show my response.

So... my questions,

Does each request create a new http.ResponseWriter? or it's use the
same?
Do you know how to indicate the web server to process each request
with different threads?

Any help is welcomed....

Fersca

[Max]

I think you are wrong.

Was are you using 1 browser or 2 different browsers?

May be your browser limits number of connections to server.

If you will block with Chrome then try to open your site with FireFox

I developing server that blocks for long time some connections and it works fine.

[Brad Fitzpatrick]

Each incoming HTTP request already starts a new goroutine.  When your handler function returns, the HTTP request is considered over.

[Jesse McNelis]

On Tue, Jun 26, 2012 at 7:42 AM, Fersca <fer...@gmail.com> wrote:
> Do you know how to indicate the web server to process each request
> with different threads?
>

The http server by default runs each request in it's own goroutine.
(so you don't need to add the 'go' keyword anywhere in a request
handler.)
But, by default Go only uses a single thread to schedule all goroutines.
You need to set runtime.GOMAXPROCS to increase the number of threads
it will use.
http://golang.org/pkg/runtime/

In this case you don't actually need multiple threads. Since the call
to time.Sleep() will yield to the scheduler which will schedule a
different goroutine to run while that one is sleeping.



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http://jessta.id.au

[Fernando Scasserra]

Thanks! it explains why I see the print line on my console but I don't see the response on the browser, because the the http request finish before I send the response to the client.

Fersca