Microservices and Backend Development

Microservices and Backend Development
In this article, concepts about microservices from entry level to expert level will be covered. Today, the most commonly used languages in microservices, which can be developed in any language, include Java, .Net, and node.js.
In interviews, the first question asked about microservices is usually about the benefits microservices provide, when they should be used, and which methods to consider in their design.

Design Principles in Microservices

• Modularity: Services should be independent, and their purposes should have clear boundaries.
• Scalability: The dynamic structure of services must be independently scalable so that they can handle increasing load.
• Decentralization: The system should not be managed from a single area; it should have a decentralized management style that allows for loosely coupled services.
• High Availability: Designing services to be highly available is the most important point in ensuring system reliability.
• Resilience: Errors that may occur in the services as a whole and in their details must be designed to be easily handled.
• Data Management: Data management for each service should be autonomous, just as in decentralization, and a common database or table should not be shared.
• Statelessness: There should be no affinity in services; state information should not be kept constant for easy scaling and caching.
• Independent Deployment: Services must be independently deployable without needing other services.
• Observability: Services must have built-in monitoring and logging capabilities to provide visibility into how the structure operates and reacts.
• Automation: Deployment, testing, and scaling should be automated as much as possible.

Microservices Using Spring Boot Application + Spring Cloud

In the microservices framework, plugins like Spring Boot Application + Spring Cloud provide significant benefits and major advantages over competitors. It is possible to examine these under several headings.

Improved Scalability
In the microservices architecture, with the contribution of plugins, services can be developed, deployed, and scaled independently, providing better scalability.

Faster Time to Market
By splitting a monolithic application into smaller, independent services with plugins, development teams can work in parallel, develop faster, and deliver more quickly.

Resilience
With the inclusion of plugins in the system, microservices have a more independent and flexible structure, operating in a more micro fashion in areas such as failure, development, and bug resolution. As a result, a single operation engages only the relevant structure rather than the entire whole, preventing the systems from being disrupted.

Resource Usage
While in monolithic services a single resource is consumed at the highest level, supporting microservices with plugins results in more efficient usage with available alternatives.

Database Design in Microservices

Database design can proceed in different ways for each software architecture and condition. The Database Design models used for microservices are as follows:

• Database per Service -> Services have their own databases that provide autonomy.
• Shared Database -> There is a database where multiple services and systems store data.
• Event Sourcing -> There is a database that stores the trails and reports of operations in the system.
• Command Query Responsibility Segregation (CQRS) -> A high-performance database where queries and commands are separated.
• SAGA -> A database model that can handle long-running operations in different structures.
• Materialized View -> Models that provide a pre-calculated view for fast access to frequently used data.
• API Composition -> A model that allows data from multiple services and packages to be viewed together.
• Read Replicas: A model used to keep read requests off the main database; it improves performance.

Choreography in Microservices

The concept of choreography is often mentioned within microservices. This is actually a form that avoids the centralization that is considered in algorithm designs. It is a concept introduced so that services do not depend on a single hub when communicating with each other. All services become individually responsible for their own internal operations and benefits to the system.
In services handled in the choreography concept, messaging takes place between services for how behaviors will occur. At this point, depending on the message coming from another service, the current service can take a more autonomous approach to the event.
The advantageous situation within the system can itself be called choreography. As a result, dynamic process dependency in development, maintenance, and strategies is eliminated. Instead of all services being blocked, only performance is reduced until another service's process is completed, and the system's operation does not lose continuity. This also ensures that, in scenarios with security vulnerabilities, the exposure comes through a single structure only, and that intervention keeps the problem at a small scale.