Adopting microservices has helped many successful corporate organizations in the world, such as Amazon, Netflix, Uber and Etsy, succeed with their IT projects. These companies gradually dissolved their monolithic applications and modified them into microservice-based architectures to achieve super-fast scaling, business agility and higher profits.
What Are Microservices?
Microservices are software architectural styles that help create huge programs as a group of many small, autonomous services that can communicate with one another across a network. In simple terms, it is a method for creating a single application made up of many small services that can be developed, tested and deployed independently.
Each service runs in its process and communicates with other services using simple tools like HTTP resource APIs. Microservices distribute application codes in manageable, discrete chunks that are not dependent on one another. The service can be separately deployed using fully automated deployment techniques because they are created around particular business characteristics.
Microservices can be developed using many technologies and programming languages as long as they can communicate with one another using a standard API. Since they are intentionally loosely connected, modifications to one service don’t have an impact on the other services. This makes it simpler to scale, update and manage the application.
Why Build Microservices?
A key benefit of microservices lies in their scalability. With monolithic architectures, scaling the entire application to meet increased demand can be challenging. Microservices allow fine-grained scaling, where only the specific services experiencing higher loads can be scaled, thus optimizing resource utilization and cost efficiency.
Additionally, microservices foster flexibility and technological diversity. Different services within a system can be written in various programming languages or use different databases based on the specific requirements of each service.
This freedom allows developers to select the best tools and technologies for each service, optimizing performance and productivity. Moreover, microservices improve fault isolation. In monolithic systems, a single bug or issue can potentially bring down the entire application.
In contrast, microservices compartmentalize functionalities, so if one service fails, it doesn’t cascade into other parts of the application, ensuring greater resilience and easier debugging.
However, adopting microservices is not without challenges. It introduces complexities in managing inter-service communication, versioning, and data consistency between services. Additionally, it demands robust infrastructure and continuous monitoring to ensure optimal performance and reliability.
What Is Spring Boot?
Spring Boot is an open-source Java-based framework used to build a microservice. It was created by Pivotal Team and is used to create independent and production-worthy spring apps. Java programmers can use Spring Boot to build apps that can be easily executed, without the need for a full Spring setup configuration.
Spring Boot offers many advantages:
- It provides a flexible way to set up Java Beans, database transactions and XML customizations.
- It maintains representational state transfer (REST) endpoints and offers strong batch processing.
- Not much needs to be manually configured with Spring Boot as everything is automatically configured.
- It provides a spring application based on remarks and labels.
- It eases dependency management.
Building Microservices With Spring Boot
Creating a new microservice can seem overwhelming as there are numerous factors to be considered. However, Spring Boot has a wide range of libraries that can help you build it. Following are the steps to build a microservice using Spring Boot and Spring Cloud.
1. Core Microservices
Employee service, department service and organization service are three of the core backend Spring Boot microservices that have to be created. Each of these microservices has its database.
As a database, these microservices can use relational or NoSQL databases. So make sure that each microservice in your project has its database whenever you build one. NoSQL databases are those that store data in a format other than relational tables.
NoSQL databases are not tabular as they handle data storage differently. According to the data model, these databases are categorized and typical varieties include documents, graphs, columns and key values.
2. Microservices Communication
Once the above three microservices are built, the next step is to examine how these microservices interact with one another. There are various methods for calling a REST API from one microservice to another.
REST API is a set of guidelines that programmers adhere to when building an API. One of these rules specifies that when you link to a particular URL, you should be able to access a specific piece of information or a resource.
There are two different categories of communication; synchronous and asynchronous. When using synchronous, you can send an HTTP request from one microservice to another using the HTTP protocol. While in asynchronous communication, a message broker must be used for asynchronous communication between numerous microservices.
3. Registry and Discovery Pattern
After understanding how microservices interact with one another, the next step involves how to construct a Service Registry and Discovery mechanism in the microservices project.
The Service Discovery method functions as a registry where the location of the instances is kept track of. A network path is dynamically assigned to these instances. As a result, a client must use a Service Discovery mechanism to request a service.
To avoid hard-coding hostnames and ports, you can use the service registry and discovery pattern.
4. Config-Server to Externalize the Configurations
In the next step, the configurations of all three microservices will then be transferred into a single git repository using a configuration server. You can use the Spring cloud configuration module to set up a configuration and transfer files into one location.
5. API Gateway Pattern
Once you understand how to transfer configuration files through the configuration server, the API gateway implementation comes next. It is the key element of the microservices design. Therefore, if a client has to call one of the microservices, it must remember the host names and ports of all of them.
The API gateway enters the scene as a potential solution where a client can request the central component. Thus, whenever a client submits a request to the backend microservices, the client must first send a request to the API gateway, which will then route the request to the relevant microservice under the routing rules.
6. Distributed Tracing
Once you build the API gateway in microservices, you can implement distributed tracing. We can use the Spring Cloud module to implement distributed tracing in our microservices project as it offers this feature.
Distributed tracing is the process of tracking application requests as they move from frontend devices to backend services and databases. It can be used by developers to analyze requests that have high latency or mistakes. They help developers monitor and troubleshoot performance issues.
Distributed tracing systems help in measuring the duration of important user actions. It combines performance information from certain services, enabling teams to quickly assess if they are meeting SLAs.
7. Circuit Breaker Pattern
Services in a microservices architecture must communicate with one another. Due to network connectivity challenges, there may occasionally be service interruptions or lengthy response times to queries. A single microservice failure can have a substantial impact on system availability and spread to all other microservices.
By using the circuit breaker arrangement, the employee service can reduce the number of calls to the department service. Every time a department service is completed, this circuit breaker design will assist employee service in returning a default response to the API Gateway, which will then be provided to the client.
Leveraging Spring Boot to build microservices empowers developers to embrace the full potential of modern software development.
By adopting microservices, organizations can break down complex applications into manageable units, enabling seamless collaboration among development teams and accelerating the deployment of new features. Spring Boot’s robust ecosystem provides essential tools for inter-service communication, data management, security, and monitoring, simplifying the development journey.
As the IT landscape continues to evolve, mastering the art of building microservices with Spring Boot opens up a world of possibilities for creating agile, resilient, and cloud-native applications.