Are you tired of hearing how "simple" it is to deploy apps with Docker Compose, because your experience is more one of frustration? Have you read countless blog posts and forum threads that promised to teach you how to deploy apps with Docker Compose, only for one or more essential steps to be missing, outdated, or broken?
Let's assume that you're building a small CakePHP application which requires PHP's intl extension for internationalisation support, and PDO's PostgreSQL driver, for the purposes of this tutorial. To install it, you need to install libicu-dev, which you can see in the small Dockerfile example below.
FROM php:8.3.7-apache-bookworm
RUN apt-get update \
&& apt-get install -y libicu-dev \
&& docker-php-ext-install bcmath intl pdo pdo_mysql
RUN a2enmod rewrite
The essence of the post is to encourage people to remove or clean up package manager caches when building images in Dockerfiles, so that the images are as small as possible.
I'll use APT and APK as examples, showing how to clean them with commands such as apt clean, and rm -rvf.