Swimming pool semaphores by Valentin Deleplace

There are 2 easy ways to implement a semaphore with a buffered channel, in order to limit the concurrent access to a resource. Let's illustrate this with a swimming pool! Then, we'll see in a real use case how to extend sync.WaitGroup and errgroup.Group to leverage concurrency without hitting DB connections exhaustion errors. I'm a developer of backends, cloud architecture, performance, algorithms (big-O), databases, and UX. I love coding in Go. I work as a Developer Advocate for Google Cloud Platform.