Creating a Real-Time Pub/Sub Server using Cowboy in Elixir

This article provides a detailed guide on building a lightweight real-time pub/sub server in Elixir using Cowboy, an efficient HTTP server for Erlang/OTP. It begins by explaining the benefits of using Cowboy, particularly when minimal overhead and tight control over connections are necessary, which makes it suitable for real-time streaming services. The article walks through the entire process of setting up an Elixir application with Cowboy, defining essential modules for handling HTTP requests, WebSocket connections, and managing topics using GenServer and ETS for message storage. By the end of the guide, developers will understand how to implement publish and subscribe functionality, as well as introspection endpoints for monitoring the system. The content clearly delineates scenarios where Cowboy outshines Phoenix, underscoring its utility in building focused services and minimizing resource usage. Throughout the article, practical code snippets provide tangible examples of implementing key features for a functional messaging service.