Nginx mirror not forwarding to mirror link-CodePudding

I currently have this nginx setup:

events {
    worker_connections  4096;
}

http {    
    log_format upstreamlog '[$time_local] Forwarding $request from $remote_addr to: ($upstream_addr $request_uri $request) - Statuscode: $upstream_status Response time: $upstream_response_time';
    log_format upstreamlogmirror '[$time_local] Forwarding mirror $request from $remote_addr to: ($upstream_addr $request_uri $request): Statuscode: $upstream_status Response time: $upstream_response_time';

    server {    
        listen        0.0.0.0:80;
        listen        0.0.0.0:443;

        location / {
            access_log  /dev/stdout upstreamlog;
            mirror /mirror;
            proxy_pass https://first.service.com/api/;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }

        location /mirror {
            internal;
            proxy_pass http://127.0.0.1:55555/;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }
    }

    server {    
        listen 127.0.0.1:55555;
        location / {
            access_log  /dev/stdout upstreamlogmirror;
            proxy_pass https://second.service.com/;
        }
    }
}

However, I am facing some difficulties with this.

It seems like the mirrored server is indeed receiving a request (I see it in the logs), but when requesting e.g. https://localhost/myroute, it will properly forward to https://first.service.com/api/myroute, but the second service is only sent to https://second.service.com/ without having the route appended.

I also tried to do the whole thing with this setup:

        location / {
            access_log  /dev/stdout upstreamlog;
            mirror /mirror;
            proxy_pass https://first.service.com/api/;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }

        location /mirror {
            internal;
            access_log  /dev/stdout upstreamlogmirror;
            proxy_pass http://second.service.com/;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        }

This works just fine, but in this case I am not getting any logs at all.

Where am I going wrong here?

CodePudding user response：

You have to add the $request_uri to the proxy_pass to send the full URI to the second, mirrored backend. Just tested in my lab:

server {
  listen 9001;
  log_subrequest on;
  access_log /var/log/nginx/mirror.log upstream_time;
  location / {
    mirror /mirror;
    proxy_pass http://127.0.0.1:9002/;
  }

  location = /mirror {
    proxy_pass http://127.0.0.1:8000$request_uri;
 }
}

server {listen 9002; return 200 "Server 1\n";}

Make sure adding the internal directive to the mirror location.

As responses from the mirror will be ignored I am using an Python http.server to fake my backend and see the trace the incoming requests.

python3 -m http.server 8000

Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...
127.0.0.1 - - [05/Feb/2022 22:00:45] code 404, message File not found
127.0.0.1 - - [05/Feb/2022 22:00:45] "GET /test/something HTTP/1.0" 404 -

The NGINX logs after submitting a simple curl curl 127.0.0.1:9001/test/something

127.0.0.1 - - [05/Feb/2022:22:08:46 -0500] "GET /test/something HTTP/1.1" 404 156 "-" "curl/7.29.0" upa="127.0.0.1:8000/test/something" rt=0.003 uct="0.000" uht="0.003" urt="0.003"
127.0.0.1 - - [05/Feb/2022:22:08:46 -0500] "GET /test/something HTTP/1.1" 200 9 "-" "curl/7.29.0" upa="127.0.0.1:9002/test/something" rt=0.003 uct="0.000" uht="0.001" urt="0.001"

To have the correct URI in your log file, make sure you are adding $request_uri to your logformat. The $uri variable will change to /mirror.