GenServer as a Coordinator

In the previous lesson, we peeked at all of the concerns a GenServer handles for us when we attempted to implement a mutable counter. At the same time, we have also shown how we can implement a very simple counter with agents in four lines of code. Behind the scenes, agents are implemented with GenServers. Therefore, if we want to use a GenServer, we need more than just a mutable state. One such example is when we need a process to coordinate the activities of multiple other processes.

Allocation in concurrent systems

In a concurrent system, coordinating the allocation and release of resources is sometimes demanding. Elixir developers rarely rely on try/catch or try/rescue. In many cases, it’s cleaner to use tuples and pattern matching because operations such as File.read/1 return {:ok,contents} or {:error, reason} instead of failing with an exception. There’s more to the story, though.

The try and catch or rescue operations are just not enough when processes are involved. If a process terminates due to another linked process, we’re done. We can’t catch, after, or rescue across processes.

Check this out, by running the commands written below.