Hands-On Software Engineering with Golang

Implementing an in-memory, thread-safe queue

For the majority of applications, using an in-memory queue implementation such as the one presented here should suffice. Implementing support for other types of queue systems (for example, Kafka, nats-streaming, or even plain files) is left as an exercise for you.

Let's start by defining the inMemoryQueue type and its constructor:

type inMemoryQueue struct {
    mu   sync.Mutex
    msgs []Message

    latchedMsg Message
}

func NewInMemoryQueue() Queue {
    return new(inMemoryQueue)
}

As you can see, the in-memory queue is nothing more than a slice of Message instances – a slot for storing the message that's being currently pointed to by an iterator and a sync.Mutex for serializing access to the list of messages. ...