The Foundations of Microservices: Understanding Microservices Design Principles and Architecture

Today, microservices are the most common way to build an application. Even though these architectures are well-known for the problems they solve, even professionals with a lot of training can need help putting them in place. Instead, they can look for patterns in the issues and make fixes that can be used more than once to speed up the app. So, in this article, I’ll talk about the essential Microservices Design Patterns that should be used to create a Microservices architecture that works.

What Are Microservices?

Microservices is an architectural design for making a distributed application using containers. They get their name because each application function operates as an independent service. This architecture allows each service to scale or update without disrupting other services in the application. A microservices framework creates a massively scalable and distributed system, which avoids the bottlenecks of a central database and improves business capabilities, such as enabling continuous delivery/deployment applications and modernizing the technology stack.

What Is Microservices Architecture?

Microservices architecture treats each part of an application as a separate service that can be changed, updated, or shut down without affecting the rest of the application.

In the past, applications were built as a single piece of software. When you add new features, you must reconfigure and update everything in the application, from processes and communications to security. Traditional monolithic apps have long lifecycles, are rarely updated, and changes usually affect the whole app. This expensive and time-consuming process slows down updates and changes to enterprise applications.

This problem was taken into account when designing the architecture. All services are made on their own and put into place separately. This architectural style lets services grow or shrink depending on a business’s needs. Changes can be made quickly to services without affecting other parts of the application. One of the benefits of microservices is that they allow for continuous delivery.

Microservices architecture has the following attributes:

The application is broken up into separate, modular parts.

• Applications can be spread across multiple clouds and data centres

• Only the individual microservices need to be updated to add new features

 • Network services must be software-defined and run as a fabric for each microservice to connect to.

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What Are The Design Patterns Of Microservices?

  • Aggregator Pattern

An aggregator is a website or programme that brings together related pieces of data and shows them. So, even in Microservices patterns, Aggregator is just a simple web page that calls on different services to get the needed information or functionality.

Also, since the output source is split when a monolithic architecture is broken up into microservices, this pattern is proper when you combine data from multiple services to get an output. So, if we have two services with their database, an aggregator with a unique transaction ID would collect the data from each microservice, apply the business logic, and then publish it as a REST endpoint. In the future, the services that need the collected data can use the collected data.

The DRY principle is the basis for the Aggregate Design Pattern. Using this principle, you can separate the logic into a group of microservices and combine that business logic into a single service.

  • Chained or Chain of Responsibility Pattern:

Chained or Chain of Responsibility Design Patterns combine chained outputs into one output. So, if you have three services in a row, Service A is the first to get the client’s request. Then, this service talks to the next service, Service B, and gets data from it. Lastly, the second service talks to the third service to make the combined output. These services use HTTP requests or responses simultaneously to send and receive messages. Also, the client gets an output once the request goes through all the benefits and the answers are made. So, making a shorter chain is best since the client must wait until it is done.

One more important aspect you need to understand is that the request from Service A to Service B may look different from Service B to Service C. Similarly, the response from Service C to Service B may look different from Service B to Service A.

  • Asynchronous Messaging Design Pattern

In synchronous messaging, it’s clear that the client gets stuck or has to wait for a long time. But if you don’t want the customer to wait too long, you can use asynchronous messaging. In this type of microservices design pattern, all of the services can talk to each other, but they do not do so in order so, if you think about three services, Service A, Service B, and Service C. The client’s request can go straight to both Service C and Service B at the same time. There will be a line for these requests. Aside from this, the request can also be sent to Service A, and Service A doesn’t have to send its response to the same service that sent the request.

  • Event Sourcing Design Pattern

The event sourcing design pattern makes changes to the application state into events. Also, these events are saved as a series of events so that developers can keep track of when and what changes were made. So, with the help of this, you can constantly adjust the application state to cope with past changes. You can also query these events for any data change and simultaneously publish these events from the event store. Once the events are posted, you can see the changes in the application state on the presentation layer.

  • Circuit Breaker Pattern

As its name suggests, the Circuit Breaker design pattern is used to stop the request and response process if a service isn’t working. So, let’s say a client sends a bid to get data from more than one service. But one of the services needs to be fixed because of a problem. Now, you will mostly run into two issues. First, since the client won’t know that a particular service is down, the request will be sent to that service. The second problem is that the network’s resources will be used up, leading to slow performance and a bad user experience.

So, you can use the Circuit Breaker Design Pattern to avoid these kinds of problems. The client will use a proxy to call a remote service with this pattern. This proxy will act mainly like a barrier in a circuit. So, when the number of failures exceeds the threshold, the circuit breaker trips for a certain amount of time. Then, nobody can call the remote service during this timeout. Once that time is up, the circuit breaker will only let a certain number of tests through. If those tests are successful, the circuit breaker will return to how it usually works. If not, the timeout period starts over if there is a failure.

  • Decomposition Design Pattern

Developers make microservices intending to make small services, each with its functions. But separating an app into small, independent pieces has to be done logically. So, you can use the Decomposition patterns to break up a small or large application into small services.

This pattern allows you to break up an application by its business capabilities or sub-domains. For example, if you look at an e-commerce application, you can break it down by business capability and have separate services for orders, payments, customers, and products.

But in the same situation, if you design the application by breaking down the sub-domains, you can give each class its services. In this case, if you think of the customer as a class, this class will be used for customer management, customer support, etc. So, to decompose, you can use Domain-Driven Design, which breaks the whole domain model into smaller pieces called “sub-domains.” Then, each sub-domain will have its model and area of responsibility (bounded context). When developers make microservices, they make them with the scope or bounded context in mind.

Even though you might think these patterns are doable, they are only for small, single-piece applications. It takes work for big applications to determine their subdomains and business capabilities. So, the only way to break up big applications into smaller pieces is to use the Vine or Strangler Pattern.

What Are Microservices Design Principles?

 Microservices Design principles are the guidelines that help designers implement microservices-based systems which help in scaling and are easy to maintain. A few principles are:

  •  Single Responsibility Principle: Each microservice should follow and perform a single responsibility well.
  • Loose Coupling: They should be loosely coupled. Changes in one microservice do not influence other microservices.
  • Autonomous: Every microservice should be autonomous and independent, which helps in fast development.
  • Fault Isolation: Microservices are to be designed so that failure in one should not influence the entire system.
  • Resilience: Microservices should be made to check the failure correctly and maintain it quickly.
  • Continuous Delivery: Continuous delivery should enable fast and timely deployment of new microservices.

By following these principles, developers can build microservices-based systems that are easier to develop, maintain, and scale while ensuring high availability and resilience.

Some Examples Of Microservices Design Patterns Interview Questions:

Q1. What do you mean by microservices, and how are they different from monolithic architecture?

Q2. What do you mean by event-driven architecture, and how is it related to microservices?

Q3. How will you differentiate between synchronous and asynchronous communication in microservices architectures?

Q4. What do you understand by  microservices design patterns saga, and how can it be used in microservices?

Q5. What do you understand by event sourcing, and how can it be used in microservices?

Q6. What do you mean by kafka microservices design patterns?

Q7. What do you understand by microservices design patterns in c?

Q8. How microservices helps in fault-finding and scaling?

Q9. What are the few challenges faced when implementing microservices architectures, and how to solve them?

Q10. What are some microservices design patterns with examples in java?


So people with this, we come to an end of this blog on microservices design patterns. The use of microservices has become increasingly popular in today’s world due to the numerous benefits it provides. Microservices architecture gives you all these benefits: scalability, agility, fault-tolerance, faster development, various technologies, and modularity. Because of these benefits, businesses can respond quickly to changing market demands, improve performance and reliability, shorten the development cycle, and speed up time to market. 

Microservices architecture has helped companies like Netflix, Amazon, Uber, and Airbnb make complex software with features. Microservices are a flexible and scalable way to build modern apps that handle large amounts of data and real-time processing. It is expected that their use will continue to grow in the future. The Vine or Strangler Pattern is the only way to break up big, single-piece applications.

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