Microservices architecture is a distinctive method of developing software systems that focuses on building a single-function module with well-defined operations and interfaces. This trend has grown so popular in recent years as enterprises want to become more agile and move towards DevOps and continuous testing. Microservices have many benefits for large level enterprises like Netflix, Amazon, Paypal, and other tech starters have evolved from monolithic to microservices architecture.
Monolithic application means the application is built as a single autonomous unit. It makes changes to the application slow as it effects the entire system. If you need to modify a small section of code, you might require to build and deploy a new version of the software. Scaling specific functions of an application means you have to scale the entire application.
Microservices solve monolithic application challenges by building an application as a package of small services, each running in its process and are independently deployable. The services may be written in different programming languages. They may use different data storage techniques, and this results in the development of systems that are scalable and flexible, it needs a dynamic makeover. These services are often connected via APIs and can leverage many of the same tools and solutions that have grown in RESTful and web service ecosystem. Testing APIs can help to validate the flow of data and information throughout the microservice deployment.
Key metrics of Microservices architecture
Three key metrics you should define for microservices architecture are:
- Rate- The number of requests your services are serving per second.
- Errors- Number of failed requests per second.
- Duration- The amount of time each request takes.
By measuring these metrics helps you to analyze the service and error rates so that you can scale operations teams accordingly. This also reduces the amount of service-specific training the team needs and reduces the service-specific cases the on calls need to memorize higher incident response scenarios, and this has been referred to as the cognitive load.
Microservices for Golang
Go is a new language compared to other languages. It has many advantages as programs that are coded in golang are more robust. They allow applications to withstand heavy loads with loaded services. Golang is more suited for multiprocessor systems and web applications. The most use of golang is when an application needs to be scalable; there is one language that can perfectly fit the criteria, i.e., Golang. The reason is its inheritance with C-family programming languages as components written in golang are easier to combine with components coded in other languages that reside in the same family class. It is much more efficient than C, C++.
Frameworks used in Golang for Microservice Architecture.
Go Micro is the most popular RPC framework. It is a pluggable RPC framework and has automatic service discovery, i.e., Applications are automatically registered with the service discovery system. It supports load balancing as it helps in balancing the requests between the instances of the services. It supports both synchronous and asynchronous communication modes.
It has three layers, and the first layer is defined for service absorption. The second layer is a client-server model that has blocks and are used for writing service, and the client provides an interface. The third layer has plugins, and that is:
- Broker – It works as asynchronous communication and provides an interface for the messages.
- Codec used for encryption and decryption of the messages.
- Registry – It is for service search facility.
- Selector – Used for load balancing abstraction build upon registry.
- Transport – The channel for synchronous request communication between services.
Go Kit is a programming toolkit for building microservices. It is a library that can be imported in a binary package. It provides you with the packages for:
- Authentication- You will get BasicAuth and JWT
- Transport- It is for HTTP,gRPC.
- Logging- It provides you interface for structured logging and services
- Metrics- Used for CloudWatch, Graphite and others
- Tracing- Opentracing and Zipkin
- Service Discovery- For consul Eureka and others
- Circuit breaker- For Hystrix implementation in Go
Gizmo is a microservice toolkit by the New York Times. It helps to put server and pubsub daemons through packages. Gizmo exposes following packages
- Server- It offers server implementations. For example: SimpleServer(over HTTP) and RPCServer(over gRPC). The kit package is based on Go Kit.
- Config- It has configurations of JSON blobs, JSON files or environment variables
- PubSub- It provides generic interfaces for consuming data from queues and then publishes.
- PubSubtest- It contains test implementations of subscriber and publisher interfaces.
- Web- It exposes the functions for parsing from request and payload queries.
It is a framework for developing microservices in Go. It exposes Server packages and RPC Clients and automatically registers with a service discovery system Kontrol. Kontrol is written in Kite, and it’s a service itself. This means kite microservice works well within its environment.
Microservices for Java
Java is a great language to use when developing a microservice architecture. Let us find out how?
In the monolithic application, you will have to call the method inside your controller and move all its helper classes to its project under source control and deploy it independently. The whole extraction process does not make module a microservice. You will have to do two things:
- Call all separately deployable services as microservices independent of domain boundaries and size.
- Focus on inter-service communication because your microservice need ways to talk to each other.
There are two ways of communication in Java microservices:
- Synchronous communication
It is usually done via HTTP and REST- services that return XML or JSON. This is used when you need an immediate response.
- Asynchronous communication
It is usually done through messaging with a JMS implementation or with a protocol like AMQP. This is used when you do not need an immediate response.
Also, Read Java Microservices for Scalable Applications
Microservice with Spring Boot
Spring Boot gives you Java application to use with your apps via an embedded server. It uses Tomcat, and you do not use Java EE containers. It has all the infrastructures that your application needs. Spring boot is available for all applications, whether it is a security or any other big data application. It includes
- Spring IO Platform: It is an enterprise-grade distribution for versioned applications.
- Spring framework: It is for transaction management, data access, messaging and other web apps.
- Spring Cloud: It is used for deploying or building your microservices.
- Spring Data: It is related to data access like map-reduce, relational or non-relational
- Spring Security: It is for authentication or authorization support.
- Spring REST Docs: For documenting RESTful services.
- Spring Social: It is for connecting social media APIs.
- Spring Mobile: It is for mobile web applications.
So there are several other Microservices framework for Java. Some are mentioned below:
Jersey– It is an open-source framework that supports JAX-RS APIs in Java and is very easy to use.
Swagger– It helps in documenting API as well as gives you development portal which allows users to test their APIs
Restlet– It helps developers to create fast and scalable Web APIs that adhere to RESTful architecture pattern. It has good filtering and routing for Java SE, Google AppEngine, Android and other major platforms.