A microservice design is a single unit that can be broken down into different modules like development, deployment, maintenance. In technical terms, a microservice system allows development of single function modules.
Let's have a look at some major advantages of microservice architecture:
Technological Flexibility
While monolithic architecture always left the developers looking for the "right tool for the job," a microservice architecture offers coexistence of multiple technologies under one cover. Different decoupled services can be written in multiple programming languages. Not only does this enable developers to experiment but also scale their product by adding additional features and functionalities.
Increased Efficiency
Microservice architecture speeds up the entire process of creation. Unlike a single unit, teams can work simultaneously on multiple components of a software system. This, in addition to increasing productivity, makes it easier to locate specific components and focus on them. Malfunctioning of a single component will not affect the entire system. Instead, this also eases error location and maintenance.
Products Not Projects
According to Martin Fowler, microservice architecture helps businesses create "products instead of projects." In simpler terms, the use of microservice architecture allows teams to come together and create functionality for business rather than a simple code. The entire team comes together to contribute to different functionalities. These can further be used for different lines of business if applicable. In addition, it also creates an autonomous, cross-functional team.
Following are some of the steps that you can take to define your microservice:-
The first step is to identify the pieces of code that are replicated under various modules. How often do you see them repeat? and how much effort goes into getting them setup each time in different modules? If the answer to all of these are high, then the scope of the microservice would be to handle just the repeating pieces of code.
Another step that you can take is to check if a module is not dependent on other modules or in simpler terms, check if it's possible that a module is loosely coupled with the rest of the services. If so, then the scope of the microservice will be the scope of the entire module.
Another very important metric to consider while defining the scope is to check if the features would be used with a heavy load. This would check if the microservice would have to be scaled up in the near future.If it does, then it's a good idea to define the scalable bits as the scope of a microservice rather than combine it with other features.
The main motive of any microservice is to have services independent of each other. This means one can edit, update or deploy a new service without hampering any other services present. This is possible if interdependence is low. A loosely coupled system is the one where one service knows too less or nothing about others.
It is important for any service to be the unique source of identification for the rest of the system. Let us take an example to understand this scenario.
After an order is placed on an e-commerce website, the user is provided with an order ID. This order ID once generated contains all the information regarding the order. As a microservice, the order ID is the only source for any information regarding the order service. So, if any other service seeks information regarding the order service, the order ID acts as the source of information rather than its actual attributes.
API Integration
Breaking down the monolithic design into multiple services means these service will coordinate and work together to form the system. But, how do these services communicate? Imagine using multiple technologies to create different services. How do they relate to each other?
Well, the simple answer would be the use of an API (Application Programming Interface). The fundamental of microservice design is using the correct API. This is crucial to maintaining communication between the service and the client calls. Easy transition and execution are important for proper functioning.
Another important thing to note while creating an API is the domain of the business. This definition of the domain will ease out the process of differentiating the functionality. There are several clients which are external to the system. These clients could be other applications or users. Whenever a business logic is called, it is handled by an adapter (a message gateway or web controller) which returns the request and makes changes to the database.
Data Storage Segregation
Any data stored for a specific service should be made private to that specific service. This means any access to the data should be owned by the service. This data can be shared with any other service only through an API. This is very important to maintain limited access to data and avoid "service coupling."
Traffic Management
Once the APIs have been set and the system is up and running, traffic to different services will vary. The traffic is the calls sent to specific services by the client. In the real world scenario, a service may run slowly, thus, causing calls to take more time. Or a service may be flooded with calls. In both the cases, the performance will be affected even causing a software or hardware crash.
This high traffic demand needs management. A specific way of calling and being called is the answer to a smooth flow of traffic. The services should be able to terminate any such instances which cause delay and affect the performance.
This can also be achieved using a process known as 'auto-scaling' which includes constant tracking of services with prompt action whenever required. In some cases, a 'circuit breaker pattern' is important to supply whatever incomplete information is available in case of a broken call or an unresponsive service.
Minimal Database Tables (Preferably Isolated Tables)
Accessing database tables to fetch data can be a lengthy process. It can take up time and energy. While designing a microservice, the main motive should revolve around the business function rather than the database and its working. To ensure this, even with data entries running into millions, a microservice design should have only a couple of tables. In addition to minimum numbers, focus around the business is key.
Constant Monitoring
The microservice monitoring tools will monitor individual services and later combine the data by storing it in a centralized location. This is a necessary step while following micro-services design principles.
API performance monitoring is crucial to any microservice architecture in order to make sure the functionality stays up to the mark in terms of speed, responsiveness and overall performance of the product. Realizing the crucial part played by an API in a successful microservice architecture.
