I've been working on upgrading my local environment from 2.2.10 to 2.3.4, but can't figure out how to install the extra PHP modules for the new version (ie: sodium) using Docker. I was previously using PHP 7.1, but just rebuilt my containers with 7.3. They're up and running with no problem, but how do I go about adding the modules? I tried running
sudo pecl install -f libsodium which I thought would work, but because sodium wasn't added to the php.ini file it wasn't able to pick it up. I haven't been able to even find the .ini file inside the container, and am really at a loss here. The next thing I tried was adding it into the PHP Extensions line in docker-compose.yml, but this seems to break the ability to even run bin/magento from inside the container.
Fyi I'm new to magento and docker, so I might be missing something obvious here. Thanks in advance for any help