Correct Architecture for Micro Services with Multiple Customer Interfaces

Question

I am new to micro services and I am keen to use this architecture. I am interested to know what architecture structure should be used for systems with multiple customer interfaces where customer systems may use one or many of the available services. Here is a simple illustration of a couple of ways I think it would be used:

An example of this type of system could be:

1. Company with multiple staff using system for quotes of products

   • using products, quotes and users mirco services

2. Company with website to display products

   • using products micro service

3. Company with multiple staff using system for own quotes

   • using quotes and users micro services

Each of these companies would have their own custom build interface only displaying relevant services.

As in the illustrations all quotes, products and users could be stored local to the mirco services, using unique references to identify records for each company. I dont know if this is advisable as it could make data difficult to manage and could grow fast making it difficult to manage.

Alternatively I could store such as users and quotes local to the client system and reference the micro services for data thats generic. Here mirco services could be used just to handle common logic and return results. This does feel someone illogical and problematic to me.

I've not been able to find anything online to explain the best course of action for this scenario and would be grateful for any experienced feedback on this.

Answer 1

After much research following various courses online, video tutorials and some documentation provided by Netflix, I have come to understand the first structure in the diagram in the best solution.

Each service should be able to effectively function independently, with the exception of referencing other services for additional information. Each service should in effect be able to be picked up and put into another system without any need to be aware of anything beyond the API layer of the architecture.

I hope this is of some use to someone trying to get to grips with this architecture.

Answer 2

I am afraid you will not find many useful recipes or patterns for microservice architectures yet. I think that the relative quiet on your question is that it doesn’t have enough detail for anybody to readily grasp. I will make a wag:

From first principles, you have the concept of a quote which would have to interrogate the product to get a price and other details. It might need to access users to produce commission information, and customers for things like discounts and lead times. Similar concepts may be used in different applications; for example inventory, catalog, ordering [ slightly different from quote ].

The idea in microservices is to reduce the overlap between these concepts by dispatching the common operations as their own (micro) services, and constructing the aggregate services in terms of them. Just because something exists as a service does not mean it has to be publicly available. It can be private to just these services.

When you have strained your system into these single function services, the resulting system will communicate more, but will be able to be deployed more flexibly. For example, more resources &| redundancy might be applied to the product service if it is overtaxed by requests from many services. In the end, infrastructure like service mesh help to isolate the implementation of these micro services from the sorts of deployment considerations.

Don’t be misled into thinking there is a free lunch. Micro service architectures require more upfront work in defining the service boundaries. A failure in this critical area can yield much worse problems than a poorly scaled monolithic app. Even when you have defined your services well, you might find they rely upon external services that are not as well considered. The only solace there is that it is much easier to insulate your self from these if you have already insulated the rest of your system from its parts.