Circular relationship diagram for Microservices and Serverless architectures

Microservices is the trend for splitting large systems to individual self contained subsystems. With the advancement of Serverless offerings more and more systems are created or moving towards Microservice approach.

Is Microservice same as Serverless?

Before we go further let us clarify the difference between Microservice and Serverless. There could be some readers who thinks both are same and Serverless is more advanced. To be frank, there are fundamental differences between these two.

Microservice - It is about splitting the systems into small sub systems which are deliverable by them selves. Microservices can be hosted either in Cloud or in onpremise data centers. Microservice has to manage its own data and that data should never be touched by other systems directly.
If the system consists of couple of services and both are maintained by same team, those services doesn't necessarily be separate.

Serverless - It is about freeing the developers from worrying about underlying infrastructure. They just have to write the code and give to the hosting environment. The environment takes care from there about scaling, fault tolerance, patching etc... to maintain a promised parameters such as  predictable throughput, OS level security etc...

Problem

The problem with Microservice is the integration of Microservices. If it is single big monolith system the integration is handled by the class relationship. When we move to Microservice the complexity is moved to the service integration level from the class level. The overall complexity of the system is not changing. It would be easy when we start Microservice based system from scratch or convert existing. But it gets difficult when the count of Microservices goes beyond 50 or 100. Especially to understand their relation to each other. Who calls who and what protocol ie ie dependency. 

The technical solution for this problem is to implement Service mesh or service discovery mechanism so that we have the connection details at central place.

But how do we create a diagram to represent those relationships. If we use traditional blocks and arrows model, it will take more time to understand than the time for coding the same. So lets take another approach.

Circular Relationship Diagram

It doesn't seems that there is a standard name for a diagram which puts the entities in the edge of a circle and shows connections by drawing lines between those through the circle. As programmers lets try to generate one by code than buying a software.

D3.JS for Circular Relationship Diagram

Most of us would be familiar with the D3.JS library for charting in the browser. That library have the support for creating circular relationship diagram. Below goes one link.

http://mbostock.github.io/d3/talk/20111116/bundle.html

The above is not intended for plotting the relationship between the Microservices. But as programmers we can easily change its data to provide our Microservice relationship. The above link doesn't need any server side coding. All it needs is web server to serve HTML pages. It can be IIS, Apache or anything.

Thanks to the D3 library and author of the sample.

Other references

https://github.com/nicgirault/circosJS
https://modeling-languages.com/javascript-drawing-libraries-diagrams/