Wednesday, February 24, 2016

Introduction into Microservice architecture

The purpose of this post and future related ones is to understand which are the advantages and disadvantages of Microservice architecture. This blog post is meant to get you familiar with this topic and represents a first step towards reaching the end goal.
Understanding what microservice architecture is and then identifying the advantages and the disadvantages of this architecture, it is first required to define some concepts like software architecture and software pattern. 
Software architecture refers to the high level structures of a software system, the discipline of creating such structures, and documentation of these structures. These structures are needed to reason about the software system. Each structure comprises software elements, relations among them, and properties of both elements are relations. The architecture of a software system is a metaphor, analogous to the architecture of a building. Wiki
As microservices architecture is an architectural pattern let us have a look over its definition. An architectural pattern is a general, reusable solution, to a commonly occurring problem in software architecture within a given context. Architectural patterns are similar to software design pattern but have a broader scope. The architectural patterns address various issues in software engineering, such as computer hardware performance, limitations, high availability and minimization of a business risk. Some architectural patterns have been implemented within software frameworks. Wiki
Because the microservice architecture comes in contrast with the monolithic architecture let us shortly review what a monolithic architecture is. 
In software engineering, a monolithic architecture describes an architecture in which the application single-tiered software application, its user interface and data access code are combined into a single program from a single platform. A monolithic application is self-contained, and independent from the other computing applications. The design philosophy is that the application is responsible not just for a particular task, but can perform every step needed to complete a particular function. Martin Fowler article
Today, some personal finance applications are monolithic in the sense that they help the user carry out a complete task, end to end, and are “private data silos” rather than parts of a larger system of applications that work together. Martin Fowler article
Microservice architecture can be defined as an architectural pattern or style in which a software system is developed as a group of smaller services, each running in its own process and communicating with each other using lightweight mechanism such as HTTP. The services should be built around business capabilities and should be independently deployable. The services should be small, highly decoupled and should focus on doing small tasks, facilitating a modular approach for building a system.

Motivation


The development of monolithic applications becomes slower as the application grows, so does grows the frustration of the developers. Large applications are hard to manage and most often doing a small change takes days to identify the impact and hours to write the code, afterwards it might take few days to pass review sessions and run automated suite of tests. These issues are some of the causes which made developers to welcome the microservice architecture which breaks down things into manageable pieces.
Following this architecture means that a big team can be split into smaller teams organized around microservices, these small teams become autonomous and fully responsible of their developed service. Fear of change will not prevent developers to fix issues or create new features, besides this the efficiency and the development speed is visible increased.
Developers feel more comfortable when managing smaller code bases than managing a monolithic one, this means that creativity is stimulated and development frustration is less likely to appear.
Another great thing which is achieved using this architecture is that developers are kind of forced to develop the application into a modular way; it also allows reusing services over multiple applications.

More about microservices..

In future posts we'll discuss more about Microservice architecture vs Monolithic architecture, advantages and disadvantages of Microservices and putting this architecture to practice.