Docker PHP Nginx without mouting source code to Nginx

docker-compose.yml

version: '3.4'
services:
  app:
    image: php:7.2-fpm-alpine
    restart: unless-stopped
    volumes:
      - ./:/var/www/html
      - ./www.conf:/usr/local/etc/php-fpm.d/www.conf

  webserver:
    image: nginx:1.17-alpine
    restart: unless-stopped
    ports:
      - "8000:80"
    volumes:
      # - ./:/var/www/html
      - ./nginx.conf:/etc/nginx/conf.d/default.conf

nginx.conf

server {
    listen 80;
    index index.php index.html;

    error_log  /var/log/nginx/error.log;
    access_log /var/log/nginx/access.log;

    root /var/www/html/public;

    location ~ \.php$ {
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_pass app:9000;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_param PATH_INFO $fastcgi_path_info;
        fastcgi_hide_header X-Powered-By;
    }

    location / {
        try_files $uri $uri/ /index.php?$query_string;
    }

    location ^~ /css {
        add_header  Content-Type    text/css;
        fastcgi_param PATH_INFO $fastcgi_path_info;
        fastcgi_pass app:9000;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_hide_header X-Powered-By;
    }

    location ^~ /js {
        add_header  Content-Type    application/javascript;
        fastcgi_param PATH_INFO $fastcgi_path_info;
        fastcgi_pass app:9000;
        fastcgi_index index.php;
        include fastcgi_params;
        fastcgi_split_path_info ^(.+\.php)(/.+)$;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        fastcgi_hide_header X-Powered-By;
    }
}

www.conf

[www]
user = www-data
group = www-data
listen = 127.0.0.1:9000
pm = dynamic
pm.max_children = 5
pm.start_servers = 2
pm.min_spare_servers = 1
pm.max_spare_servers = 3
security.limit_extensions = .php .php3 .php4 .php5 .php7 .css .js