nginx.conf

server {
    listen 80;
    server_name _;
    
    set $site_root /data/www/$host;
    set $log_root $site_root/logs;
    
    location / {
    
      root $site_root;
        set $backend "";
        rewrite_by_lua '
            -- load global route cache into current request scope
            -- by default vars are not shared between requests
            local routes = _G.routes

            if routes == nil then
                routes = {}
                ngx.log(ngx.ALERT, "Route cache is empty.")
            end

            local route = routes[ngx.var.http_host]
            if route == nil then
                local redis = require "redis"
                local client = redis.connect("localhost", 6379)
                route = client:get(ngx.var.host)
            end

            -- fallback to redis for lookups
            if route ~= nil then
                ngx.var.upstream = route
                routes[ngx.var.http_host] = route
                _G.routes = routes
            else
                ngx.exit(ngx.HTTP_NOT_FOUND)
            end
        ';

        proxy_buffering off;
        proxy_redirect off;
        proxy_set_header X-Real-IP  $remote_addr;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://$backend;
        
        set $log_root "/var/log/nginx";
    }
    
    error_log  $log_root/error.log  info;
    access_log  $log_root/access.log  main;
}