I would like to extract the session key, master key and premaster key in TLS connection. In my case nginx plays TLS termination. So I want to see those key in nginx side.
Here is my nginx.conf

user  nginx;
worker_processes  1;
env SSLKEYLOGFILE=/tmp/premaster.txt;
env LD_PRELOAD=/usr/local/lib/libsslkeylog.so;

error_log  /var/log/nginx/error.log debug;
pid        /var/run/nginx.pid;

events {
    worker_connections  1024;
}
ssl_engine pkcs11;
http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;
    server {
    listen 80;
    listen 443 ssl;
    ssl_protocols    TLSv1.2 TLSv1.3;
    server_name www.wannacoffee.com wannacoffee.com;
        ssl_certificate /etc/ssl/certs/coffeeweb.crt;
        ssl_certificate_key "engine:pkcs11:pkcs11:token=mimi;object=coffeekey;type=private;pin-value=1234";
    root /var/www/html;
        index index.html;  
    location /small {
            root /var/www/html;
        }

        location /medium {
            root /var/www/html;
    }

        location /encrypt {
        proxy_pass http://127.0.0.1:5000;
            proxy_redirect  http://localhost:5000/ /;
        proxy_read_timeout 60s;

        # May not need or want to set Host. Should default to the above hostname.
        proxy_set_header          Host            $host;
        proxy_set_header          X-Real-IP       $remote_addr;
        proxy_set_header          X-Forwarded-For $proxy_add_x_forwarded_for;
    }
    
    }    

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    log_format ssl_handshake '$remote_addr - $remote_user [$time_local] '
                             '"$request" $status $body_bytes_sent '
                             '"$http_referer" "$http_user_agent" '
                             '$ssl_protocol $ssl_cipher $ssl_session_reused';
       
    access_log  /var/log/nginx/access.log  main; 
    access_log /var/log/nginx/ssl_handshake.log ssl_handshake;
    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

At the client sides, I did curl then cat /tmp/premaster.txt in server side, but It is empty. I did restart daemon and nginx after add SSLKEYLOGFILE to configuration.
Please help, thank you.