Concurrent Publish/Subscriber design pattern
In this section, we will implement the Observer design pattern that we showed previously on Behavioral patterns, but with a concurrent structure and thread safety.
Description
If you remember from the previous explanation, the Observer pattern maintains a list of observers or subscribers that want to be notified of a particular event. In this case, each subscriber is going to run in a different Goroutine as well as the publisher. We will have new problems with building this structure:
- Now, the access to the list of subscribers must be serialized. If we are reading the list with one Goroutine, we cannot be removing a subscriber from it or we will have a race.
- When a subscriber is removed, the subscriber's Goroutine must be closed too, or it will keep iterating forever and we will run into Goroutine leaks.
- When stopping the publisher, all subscribers must stop their Goroutines, too.
Objectives
The objectives of this publish/subscriber are the same...
