How to log nginx mirror requests

Question

I have nginx server with configuration:

location / {
    mirror /mirror;
    proxy_pass http://backend;
}

location = /mirror {
    internal;
    proxy_pass http://test_backend;
}

Everything works perfect, except one thing. I need to log, that mirrored request delivered. If mirrored request not delivered, I need to get some error in log file. How to do this?

Answer 1

I would use another server in the middle.

# main server
server {
    location / {
        mirror /mirror;
        proxy_pass http://backend;
    }

    location = /mirror {
        internal;
        proxy_pass http://127.0.0.1:55555;
    }
}

# mirror server
server {
    listen 127.0.0.1:55555;
    location / {
        proxy_pass http://test_backend;
        # whatever you want to log
        access_log ....;
        error_log ....;
    }
}

Answer 2

May be http://nginx.org/ru/docs/http/ngx_http_core_module.html#log_subrequest could help

log_subrequest on;