nginx proxy_next_upstream with upstream variable

Georg Pfolz

8/9/24, 9:42 AM

I find it very convenient (mainly for testing) to be able to change the upstream according to an url parameter:

upstream balance {
  server 111.111.111.111 weigth=5;
  server 222.222.222.222 weigth=6;
}

upstream server1 {
  server 111.111.111.111;
}

upstream server2 {
  server 222.222.222.222;
}

server {
  server_name myserver.servers.com;

  set $upstream balance;

  if ($arg_server = "server1") {
        set $upstream server1;
    }

    if ($arg_server = "server2") {
        set $upstream server2;
    }
  
  location / {
        proxy_pass http://$upstream/VirtualHostBase/https/$host:80/VirtualHostRoot$request_uri;
        proxy_next_upstream http_500 http_502;
    }
  listen: 80;
}

The upstream switch works, but in this configuration, the directive proxy_next_upstream does not work, because of the $upstream variable in proxy_pass (because nginx can only determine the upstream server on request and proxy_next_upstream is determined on server start or reload if my understanding is right).

Is there a way to use this url parameter and still get proxy_next_upstream working? I understand that I could use subdomains instead of url parameters, but that's something I'd like to avoid.

0 + 0

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Elon Musk

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