I got Permission denied error while running composer on ubuntu 16

I installed ubuntu 16 under AWS and try to install laravel 5.8 app, but opening server with

ssh  -i /home/user/pemkeys.pem

command I got Permission denied error while running composer

ubuntu@ip-172-31-34-88:/var/www/html/lprods$ clear
ubuntu@ip-172-31-34-88:/var/www/html/lprods$ sudo chmod -R 775 /var/www/html/lprods/
ubuntu@ip-172-31-34-88:/var/www/html/lprods$ composer install 
Cannot create cache directory /home/ubuntu/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache
Cannot create cache directory /home/ubuntu/.composer/cache/files/, or directory is not writable. Proceeding without cache
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Nothing to install or update


  [ErrorException]                                                                                                  
  file_put_contents(/var/www/html/lprods/vendor/composer/installed.json): failed to open stream: Permission denied  


install [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--no-plugins] [--no-custom-installers] [--no-autoloader] [--no-scripts] [--no-progress] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--ignore-platform-reqs] [--] [<packages>]...

ubuntu@ip-172-31-34-88:/var/www/html/lprods$ whoami
ubuntu
ubuntu@ip-172-31-34-88:/var/www/html/lprods$ lsb_release -d; uname -r; uname -i
Description:    Ubuntu 16.04.6 LTS
4.4.0-1084-aws
x86_64

As far as I remember that is not good idea to run

composer install

under root. Which steps have I to to take to install my app properly ?

Thanks!

via Chebli Mohamed