Design Patterns for Microservices

Microservices are an architectural approach that involves breaking down a monolithic application into smaller, independent services that can communicate with each other over the network. Microservices design patterns are best practices for designing and implementing microservices-based applications. These patterns are a collection of solutions to common problems that arise when developing microservices-based applications.

Especially in web development micro-service architecture is the new buzzword, and almost every company is trying to adopt a microservice-like approach. Today I want to talk about these patterns and terms, so you won't be surprised when you hear about them. Here are some common microservices design patterns:

1. Service Registry: A service registry is a central directory that holds the addresses of available microservices. It allows microservices to discover and communicate with each other.
2. API Gateway: An API gateway is the entry point for all client requests to microservices. It handles routing, load balancing, security, and other cross-cutting concerns.
3. Circuit Breaker: The circuit breaker pattern is used to handle network failures or slow responses from microservices. It detects failures and prevents cascading failures by temporarily breaking the connection with the failing service.
4. Event-driven Architecture: Event-driven architecture (EDA) is a pattern that involves using events to trigger and communicate between microservices. It provides loose coupling and allows for asynchronous communication.
5. Saga Pattern: The saga pattern is used to manage transactions across multiple microservices. It involves breaking down a transaction into a series of smaller steps, each of which can be rolled back if an error occurs.
6. Choreography vs. Orchestration: Choreography and Orchestration are two different approaches for coordinating interactions between microservices. In choreography, each service communicates with other services to achieve a goal, while in orchestration, a central orchestrator service manages the flow of communication between services.
7. Database per Service: The database per service pattern involves using a separate database for each microservice. This approach provides better scalability and performance and allows for greater flexibility in choosing the appropriate database technology for each service.
8. Stateless Services: Stateless services do not maintain any state between requests. This approach simplifies scaling and improves reliability, as any instance of a service can handle any request.

Let's check the most common tools for these architectures.

Service Registry

Not very common but a rising start for this architecture is HashiCorp's Consul.

HashiCorp Consul is a modern, open-source tool that provides service discovery, configuration management, and health checking for distributed systems. It is designed to help developers and operators automate the deployment and management of microservices-based applications.

Consul uses a central key-value store for storing configuration data, which can be accessed by microservices to retrieve their configuration settings. It also provides a service registry for tracking the availability and health of microservices, allowing other services to discover and communicate with them. You can have more information in this article,

What is HashiCorp Consul ? A s

API Gateway

NGINX is a high-performance web server and reverse proxy that is often used as an API Gateway or load balancer in microservices-based architectures. It is free, open-source software that can run on a variety of operating systems, including Linux, Windows, and macOS.

NGINX provides a range of features and capabilities that make it ideal for managing microservices-based applications. You can check their official website here => https://www.nginx.com/

Circuit Breaker

The most common tool for implementing the Circuit Breaker pattern in a microservices architecture is Netflix Hystrix. Hystrix is an open-source library that is used to implement fault tolerance and latency tolerance in distributed systems. It provides a Circuit Breaker pattern that is designed to handle failures and latency issues in microservices-based applications.

The Circuit Breaker pattern in Hystrix works by monitoring the calls to a microservice and opening the circuit when a certain threshold of failures or timeouts is reached. Once the circuit is open, calls to the microservice are immediately returned with a fallback response, without waiting for the actual response from the service. This helps to prevent cascading failures in the system and improve overall stability.

Hystrix also provides a dashboard for monitoring the health of microservices and the status of Circuit Breakers in real-time. This allows developers and operators to quickly identify and diagnose issues in the system.

In addition to Circuit Breaker, Hystrix provides other features such as request caching, request collapsing, and concurrency limiting. These features help to improve performance and scalability in microservices-based architectures.

Overall, Hystrix is a powerful and widely used tool for implementing the Circuit Breaker pattern in microservices-based architectures. Its fault tolerance and latency tolerance features help to improve the stability and reliability of microservices-based applications.

Event-driven Architecture

RabbitMQ is a high-performance, open-source message broker that can be used to send and receive messages between microservices or other distributed systems.

In EDA, events are used as the primary means of communication between different components of a system. Events represent significant changes or occurrences within the system and can be used to trigger the execution of other components or microservices.

RabbitMQ provides a flexible and reliable messaging infrastructure for implementing EDA. It uses a publish-subscribe model, where publishers send messages to specific exchanges, and subscribers receive messages from queues that are bound to those exchanges. This allows microservices to communicate asynchronously and decoupled from each other, helping to improve the overall scalability and maintainability of the system.

In addition to messaging, RabbitMQ also provides features such as message routing, filtering, and delivery guarantees, making it a robust and powerful tool for implementing EDA. It supports a wide range of protocols and APIs, including AMQP, STOMP, MQTT, and HTTP, and can be integrated with a variety of programming languages and platforms.

Saga Pattern

The most common tool for implementing the Saga pattern in microservices architecture is Apache Kafka. Kafka is an open-source distributed streaming platform that provides a highly scalable, fault-tolerant, and distributed infrastructure for handling large volumes of data.

The Saga pattern in microservices architecture is used to manage the distributed transactions that span multiple microservices. In this pattern, a Saga is a sequence of local transactions that are executed by different microservices to complete a global transaction. If any of the local transactions fail, the Saga will compensate for the previous transactions and undo their effects.

Kafka provides a distributed log that can be used to implement the Saga pattern in microservices architecture. The log can be used to track the status of the Saga and the local transactions, and to ensure that the transactions are executed in the correct order. If any of the transactions fail, Kafka can be used to trigger compensating transactions to undo their effects.

The rest of the approaches are actually design decisions for the architecture. You can use a variety of tools for these architectures but there is no common tool or approach for these decisions. You can use what you are actually used to and use the same architecture as any other tool.