Building Microservice Architecture With ASP.NET Core

The conversation about software architectures typically centers around monolithic and microservices.

In the past, a monolithic architecture was used to build a completely self-contained software program that was unaffected by other programs. Microservice architecture is essentially the opposite of a monolith because it relies on a succession of different services that can be deployed at any time. While a project is just getting started, code management, cognitive overhead, and deployment are all advantages of monolithic systems. Scalability, continuous deployment, and updates can become problematic when a monolithic application grows too large.

Instead of creating a single, inseparable application, microservices divide the work into smaller, more manageable chunks. Each of these smaller pieces contributes to the greater all-around. Decentralized and autonomously produced services are the building blocks of an application.

For many developers, a good rule of thumb is that microservices are the natural transition once monoliths grow too big or complex. For large consumer apps, organizations are increasingly turning to microservices rather than monolithic architecture to meet user demand, boost scalability, and ensure customer availability.

This blog will focus on microservices architecture and how to build said architecture using ASP.NET Core, a free and open-source web framework from Microsoft for web apps.

Let’s get started!

What is a microservice architecture?

In software development, there’s a principle that has greater significance when talking about microservices, and that is the KISS principle, which essentially means "Keep It Simple, Stupid." In software development, the KISS principle mainly refers to the fact that software should be easy to understand and use by developers and end-users.

That is where microservices come into play, but what is microservice architecture? In a microservices architecture, applications are split into independently deployable services that communicate with each other via APIs. An individual service can be deployed and scaled separately instead of as part of an entire system.

Microservices are favored by large and complicated programs for quick and frequent delivery. New features and updates can be added and implemented more quickly using a microservices architecture rather than rewriting a substantial amount of the existing code.

Each core function or service is written and delivered independently in a microservices architecture while designing apps. A microservice architecture means that if one component goes down, the app won't be affected. API contracts ensure that independent members can communicate with each other. Microservices allow you to respond to constantly changing business requirements and bring new features to market more quickly.

Benefits of microservice architecture

Services with a variety of components

Individual, loosely-coupled component services can be written, deployed, operated, modified, and redeployed without impacting the integrity of other services or the application's functionality with microservices. An application’s functionalities can be quickly and easily deployed using this method.

Highly testable and maintainable

In the case of microservices, teams can experiment with new features and quickly roll them back if they don't work out. New elements can be introduced more quickly thanks to this feature, which makes it easier to update the code. It also makes it easier to find and fix problems with specific services.

Modular, compatible, and flexible

Since each service in a software application can be disassembled and reconfigured independently, modularity makes it easier to comprehend, isolate flaws when necessary, and test. In addition to increasing efficiency and lowering costs, the fact that Microservices can be reused is now an essential aspect for developers when implementing the architecture.

Better productivity levels

Okay, so microservices allow you to break applications into smaller, self-contained fragments, making it easier for you to build and maintain, right? Well, because of its very nature, each service can be constructed separately, deployed, and managed using a variety of programming languages, technologies, and software environments. Modular components minimize the size of an application's overall codebase, making it easier to release and test new services while also allowing the development teams to divide and conquer related jobs. All of which leads to improved productivity levels.

Error isolation

As long as any upstream microservices are structured to handle errors appropriately, the unavailability of a single microservice will not affect the entire program (for example, by implementing circuit breaking).

Small teams own microservices

Agile techniques and DevOps are encouraged by microservices, which are often built by small, autonomous teams. Development cycles are shortened because teams are encouraged to operate autonomously and swiftly.

Microservices help improve app resiliency

You can quickly identify and solve performance issues when using a microservice-based design. Larger applications are unaffected by a single failure because of the increased fault separation provided by distinct modules. You can undo updates and modifications without redeploying the entire application, minimizing the risk of downtime.

Microservices are based on the company’s abilities

You can organize services around the company’s needs in a microservices architecture. To accomplish a specific task, teams must be cross-functional and comprise members with all of the necessary expertise.

Scale up or down as needed

Given the fact that DevOps teams can use a different technology stack for each module because each service is written in a particular language or technology, it's also possible to add new components to the system without having to shut down and redeploy the complete system. The performance impact of more resource-intensive features can be minimized by deploying services over numerous servers.

Fully automated Infrastructure

Infrastructure automation approaches like continuous integration (CI), continuous delivery (CD), and deployment (CD as well) are commonly used by microservices development and maintenance teams. As a result, each service may be developed and deployed independently without impacting the other groups.

In short, some of the main benefits of a microservices architecture include:

• Applications are composed of a slew of independent components that operate together as a cohesive whole.
• The functionality of a single component can be developed and understood with ease.
• Microservices are quick and easy to test.
• Components, both individually and as a whole, are easy to maintain.
• You can manage each microservice as a separate project.
• The system's low and mid-sized modularity makes it possible to break the system into smaller, more manageable parts.

How to build microservices in .NET

Starting with a monolithic architecture is the first step for many businesses, followed by implementing patterns for failure and recovery from network issues, data consistency management, and service demand monitoring, among other things. That’s the technical side of things, as the DevOps culture and reorganization of your teams are also needed.

It’s now time to decompose the monolith into microservices, which is the most challenging step. A monolithic database schema refactoring might be delicate. Identifying which datasets each service needs and any overlaps is critical. Release failures are less likely with continuous delivery, and your team is free to work on building and executing the product instead of distributing it.

Next, we’ll break down how you can build microservices using .NET.

ASP.NET Core

You can create a web application using microservice .NET Core thanks to its performance, multi-platform compatibility, and open-source license.

ASP.NET Core allows you to:

• Develop online and IoT applications, as well as mobile backends.
• On Windows, macOS, or Linux, you can use the development tools you're used to on your preferred operating system.
• Deploy on-premises or in the cloud.
• .NET Core is supported.

Microservices design patterns .NET

These are the microservices design patterns:

Aggregator

In the computer industry, an aggregator is a website or application that collects and presents linked pieces of data. For that reason, the Aggregator web page invokes other services to gather the information or perform the desired job even under Microservice designs.

The Aggregate Design Pattern follows the DRY principle. Based on this idea, you can abstract logic into composite microservices and aggregate this specific business logic into a single service.

API Gateway

Microservices are designed so that each service has its capabilities. However, a developer can encounter several issues when an application is divided into small autonomous services. Using the API Gateway design microservice pattern, API gateways can translate protocol requests from one kind to another. Similarly, it can offload the microservice's authentication/authorization duty.

Chained or Chain of Responsibility

Chained or Responsibility Chain Design Patterns generate a single output of multiple chained outputs.

Asynchronous Messaging

Under the Asynchronous Messaging microservices architecture pattern, all services can communicate with one another, but they are not required to do so sequentially.

Database or Shared Data

There is an enormous quantity of data associated with each application. When you move an application to a microservices architecture, you must ensure each microservice has the correct data for request processing. You can solve several issues using a database per service and a shared database per service.

**Event Sourcing

The event sourcing design pattern generates application state-change-related events. In addition, these events are kept as a series of events to enable developers to keep track of when they made changes.

Branch

A branch microservice design pattern is a design pattern that allows you to process requests and responses from two or more independent microservices concurrently.

Command Query Responsibility Segregator

Every microservices design uses either a per-service or shared database. We can't implement a query in the database per service paradigm because data access is confined to one database. You can employ Command Query Responsibility Segregator (CQRS) in this situation. This pattern divides the program into Command and Query. The query section handles materialized views, whereas the command part handles CREATE, UPDATE, and DELETE queries. Materialized views are updated using the event source pattern explained above.

**Circuit Breaker The Circuit Breaker microservices design pattern can halt the request-and-response process if a service fails.

**Decomposition

Microservices are built with the intention of producing small services, each with its own functionality. But the process of dividing an application into little autonomous components must be rational. Therefore, you can use the Decomposition pattern to break down a small or large application into smaller services. Using this pattern, you can decompose an application depending on either its business capabilities or its subdomains.

Testing microservices with .NET

Controllers are essential components of every ASP.NET Core API service and ASP.NET MVC Web application. As a result, you should trust in their suitability for your application. Automated testing can give this assurance by identifying mistakes before they reach production.

You must test how the controller responds to valid and incorrect inputs and the outcome of the business operation the controller does. It would help if you had the following types of testing for your microservices:

Unit testing. These tests confirm that the application's separate components function as expected. The assertions evaluate the component API.

Integration testing. These tests ensure that component interactions with external objects such as databases function as expected. Assertions can be used to test the API, UI, or side effects of activities such as database I/O, logging, etc.

Functional testing. Each microservice must pass available tests. These tests guarantee that the application functions as expected by the user.

Service testing. These tests ensure that end-to-end service use scenarios are tested, including the simultaneous testing of several services. For this form of testing, you must prepare the setting beforehand. In this instance, it refers to initiating the services (for example, by docker-compose up)

Running microservices applications in Microsoft Azure

It is not novel for software developers to break down an application into its component elements. Generally, a tiered architecture consists of back-end storage, middle-tier business logic, and a front-end user interface (UI). What has changed over the past several years is that developers are now creating cloud-based distributed apps.

Within this context, a microservices approach to design is not suitable for all projects, but it aligns more closely with the business goals outlined previously. Starting with a monolithic system may make sense if you plan to refactor the code into a microservices architecture in the future. Typically, you begin with a monolithic program and gradually decompose it in stages, starting with the functional areas that must become more scalable or agile.

When using a microservices strategy, your application comprises numerous small services. These services are delivered over a cluster of servers in containers. Smaller teams construct a scenario-centric service and independently test, version, deploy, and scale it so that the application as a whole can adapt.

Microsoft created Azure Service Fabric when it switched from supplying traditionally monolithic boxed products to delivering services. Service Fabric was shaped by the experience of developing and maintaining massive services, such as Azure SQL Database and Azure Cosmos DB.

The purpose of Service Fabric is to tackle the complex difficulties of designing and operating a service and optimizing the use of infrastructure resources so that teams can adopt a microservices approach to solve business problems. In short, Service Fabric facilitates the development of microservices-based applications by offering the following:

A platform that offers system services for deploying, upgrading, detecting, and restarting failing services, discovering benefits, routing communications, managing state, and monitoring health.

The capacity to deploy apps operating either in containers or as processes. Service Fabric is an orchestrator and container.

ASP.NET Core, Reliable Actors, and Reliable Services are productive programming APIs for building microservices-based applications. For instance, you can obtain health and diagnostics information or use the high availability incorporated.

Service Fabric is technology-agnostic regarding how a service is constructed and any technology you may use. However, it provides programming APIs that facilitate the development of microservices.

Service Fabric helps you to reuse and upgrade existing code with microservices. Application modernization consists of five stages, and you can begin and end at any level.

The levels are:

• Start with a standard single-application architecture.
• Migrate: In Service Fabric, use containers or guest executables to host existing programs.
• Modernize: Add new containerized microservices to existing containerized code.
• Innovate: Based on requirements, divide the monolithic application into microservices.
• Convert: You can convert applications into microservices. Transform current monolithic systems or create new greenfield applications.

  
  

Remember that you can start and stop at any of these stages; they are not dependent on one another to progress to the next step.

Conclusion

The goal of microservices is to reduce complexities and dependency, so you avoid costly redesigns. Start small, scale as needed, deprecate what you no longer need, create new microservices, or evolve with your customer. As microservices become more approachable by developers, apps are hotbeds of innovation and new approaches.