map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}
server {
    listen 443 ssl;
    server_name _;
    ssl_certificate /etc/nginx/tls/server.pem;
    ssl_certificate_key /etc/nginx/tls/server-key.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    location = /v1/agent {
        proxy_pass http://server:6899;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
        proxy_set_header Host $host;
        proxy_read_timeout 75s;
        proxy_send_timeout 15s;
    }
    location / { return 404; }
}