Microservice architecture or microservices is a term coined by software development leaders Martin Fowler and James Lewis in 2014. This is an organizational method of software development in which an application is built from modular components or independent services interacting through clearly defined APIs (Application Programming Interface). Each module supports a specific task and uses a simple, well-defined interface.
How do microservices work?
Microservice architecture focuses on classifying large and bulky applications. Each micro-service is designed to address specific aspects and functions of the application. It also runs a unique process and usually manages its own database. The service can generate alerts, log data, support user interfaces, process user identification or authentication, and perform various other tasks.
The microservice paradigm provides development teams with a more decentralized approach to software creation. Each service can be isolated, rebuilt, re-deployed, and managed independently of each other.
What is microservice architecture used for?
Typically, microservices are used to speed up application development. They are also often compared to service-oriented architecture. Both have the same goal of breaking a monolithic application into smaller components, but they have different approaches. Here are some examples of microservice architectures:
Site migration
It includes a significant change and reworking of the main areas of the website, such as its domain, structure, user interface, etc. The use of microservices will help to avoid downtime that is detrimental to the business and ensure smooth implementation of migration plans without any problems.
Media content
Services that offer users massive media content will benefit from using microservices, as they ensure that many requests for various subdomains around the world are processed without delay or error.
Transactions and Accounts
Microservices are ideal for applications that handle and generate large amounts of payments and transactions. Failure of the payment processing application can lead to huge losses for companies. With microservices, transaction functionality can be made more robust without changing the rest of the application.
Data processing
Microservices speed up data processing tasks because applications running on a microservice architecture can handle more simultaneous requests. Larger amounts of information can be processed in less time, allowing applications to run faster and more efficiently.
Microservice Architecture Templates
API gateways
This is an integration template that serves as a single entry point between client applications and micro services. It provides a buffer between client needs and basic system services.
Deposit
Developers can apply decomposition in two main ways:
- Domain decomposition method allows developers to define services corresponding to domain driven design, defining the region in which they will deploy the solution and the services required for that region. Each subdomain belongs to a specific part of the business, from communication with devices to user management.
- In module decomposition developers define components based on modules or functions. This allows different development teams to be responsible for each module.
Event Source Template
An operational approach to processing data controlled by a sequence of events. It records all application state changes in the order in which they were applied, creating an audit log. This is a scalable, decentralized approach to processing change.
Service Discovery Template
There are two main types of service discovery patterns:
- Client-side discovery. The service client searches the registry using the load balancing algorithm to determine the available and appropriate services. When the service starts, the server registry marks the location of the instance, and when it stops, the registry deletes the instance information.
- Server-side detections. When detected, the service consumers on the client side do not pay attention to the service registry, instead they send requests through the router. It, in turn, searches the service registry and redirects the request to the desired location as soon as the corresponding service instance is found. The API selects the correct query endpoint on the client side, so load balancing is not a problem.
Aggregator template
The aggregator template describes how the application should aggregate the data returned by each service and deliver a response to the consumer. The aggregator template handles this in one of two ways:
- the API gateway splits the request into several microservices and combines the data to be sent to the consumer;
- the composite microservice invokes each required microservice individually, collecting and converting data before returning it to the consumer.
Database or Shared Data
There are two main approaches to database architecture for microservices:
- Database for each service. With this approach, each micro-service has its own database, available only for this service. Access to it is possible only through the Microservice API.
- Shared database for each service. In this situation, the shared database template is a workable solution and a good starting point for breaking the application into smaller and more logical parts.
Characterization of Microservice Architecture
Microservice architecture consists of separate components and services; their relationship and data exchange create the functions of a complete application. Typical characteristics of a microservice architecture include the following:
Uniqueness. You can design and deploy services to perform a specific function or meet specific requirements.
Decentralization. Ideally, services have few if any dependencies, although weak connectivity requires frequent and extensive data sharing.
Sustainability. Design services for maximum fault tolerance. A single service failure does not disable the entire application.
API. Microservice architecture relies heavily on APIs and API gateways to facilitate communication.
Data separation. Ideally, each service accesses its own database or storage volume.
Benefits of Microservice Architecture
Using a microservice architecture in application development can be very useful. Below are some of its main advantages:
1. Less development time
Due to the independent nature of microservices, small development teams can work on different components in parallel to update existing features. This greatly simplifies the definition of hot services and scaling regardless of the rest of the application, and also improves the application as a whole.
2. Independent deployment
Each microservice that constitutes an application must be a full stack. This allows you to independently deploy microservices at any time. Because micro-services are inherently granular, development teams can easily work on a single micro-service to fix bugs and then re-deploy it without re-deploying the entire application.
3. Improved fault isolation
In monolithic applications, a failure of even a small component of the entire application can make it inaccessible. In some cases, determining an error can also be exhausting. With the help of microservices, it is possible to easily isolate the problem-causing component, since the entire application is divided into autonomous, fully functional software blocks. In the event of errors, other unrelated blocks will continue to function.
4. Mixed Process Stack
The technology stack refers to a set of programming languages, databases, external and internal tools, environments, and other similar components used by developers to create an application. With microservices, developers are free to choose the technology stack that works best for one particular microservice and its features. Instead of choosing one standardized technology stack that covers all the functions of the application, they can control all the stacks entirely.