Help with nginx second request

[Maxim Dounin]

Hello!

On Wed, Nov 13, 2019 at 04:38:54PM +0200, Эмануил Кант wrote:

> Hi all,
> I would really appreciate it if you could help me with nginx.
> 
> The situation is:
> Nginx (v. 1.14.2) redirects the request to the application 
> server. In case this request with the POST method and the 
> application server gives an error code 500, the response is 
> transmitted to the client.
> But nginx then makes a second request. Is there any way to 
> disable execution of the second request by nginx?
> Many thanks in advance.
> 
> Here is a part of nginx file:
> 
> #Makes upstream to the branch with response code 500
> upstream test5 {
>        server 127.0.0.1:90;
>        keepalive 20;
> }
> 
> #virtualhost that issues response code 500;
> server {
>    listen 90 default_server;
>    server_name localhost;
>    root /home/jetty/www;
> 
>        location @intercept_disabled {
>                proxy_intercept_errors off;
>                proxy_pass http://test5;
>        }
>    location /test500 {
>        return 500;
>        error_page 500 /500.html;
>    }
> }
> 
> # Redirection to virtualhost that issues response code 500;
>        location /test500 {
>            proxy_pass http://test5;
>        }

What else is configured in the server{} block with "location 
/test500"?

Results you provide (that is, two duplicate requests) and the 
unneeded "location @intercept_disabled" in the first server 
suggests that you've configured proxy_intercept_errors and 
"error_page 500" with a name-based location with additional 
proxy_pass to the same server.  And this is what causes duplicate 
requests - because this is exactly what you've asked nginx to do. 
An obvious solution is to remove this error handling or change it 
to something different.

-- 
Maxim Dounin
http://mdounin.ru/