Communication between two microservices

I'm not sure if what I am going to answer is thé right way. I'm still learning myself.. But I can tell you how I've implemented my microservices attempts..

First, I started with HTTP communication based microservices using this blog. This works fine, but the problem is, that you create dependendies between your services. Service A needs to be aware of a service B and needs to call it directly (via service discovery etc of course). This is what you generally are trying to avoid when developing microservices.

Another approach that I've started with lately, is using a message bus. It's actually the 3rd option that you touched in your question.

I have a service A, which stores persons (just an example). What the service does when it creates a new person is: It sends an event on a RabbitMQ bus: personCreatedEvent. If there are any other services interested in events like this, they can subcribe to them. These interested services keep the relevant information that they are interested in, in their own datastores.

With this last approach, there is not really a dependency between your services, because they don't communicate with each other directly. Service A is not aware of service B, because B just sends events to RabbitMQ to whichever service is interested to these events and vice versa.

Of course, you have duplications between datastores over the service. But this can be profitable as well, e.g. service B doesn't need to use the same schema or data store mechanism as service A. It only stores the relevant information in the way that is best for this service.

Have you looked at http://stytex.de/blog/2016/03/25/jhipster3-microservice-tutorial/ Part 2: inter-service communication section. It walks you through a specific example of how it is achieved