The term microservices was used for the first time in mid-2011 at a workshop of software architects. In March 2012, James Lewis presented some of his ideas about microservices. By the end of 2013, various groups from the IT industry started having discussions on microservices, and by 2014, it had become popular enough to be considered a serious contender for large enterprises.
There is no official introduction available for microservices. The understanding of the term is purely based on the use cases and discussions held in the past. We will discuss this in detail, but before that, let's check out the definition of microservices as per Wikipedia (https://en.wikipedia.org/wiki/Microservices), which sums it up as:
Microservices is a specialization of and implementation approach for SOA used to build flexible, independently deployable software systems.
In 2014, James Lewis and Martin Fowler came together and provided a few real-world examples and presented microservices (refer to http://martinfowler.com/microservices/) in their own words and further detailed it as follows:
The microservice architectural style is an approach to developing a single application as a suite of small services, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API. These services are built around business capabilities and independently deployable by fully automated deployment machinery. There is a bare minimum of centralized management of these services, which may be written in different programming languages and use different data storage technologies.
It is very important that you see all the attributes James and Martin defined here. They defined it as an architectural style that developers could utilize to develop a single application with the business logic spread across a bunch of small services, each having their own persistent storage functionality. Also, note its attributes: it can be independently deployable, can run in its own process, is a lightweight communication mechanism, and can be written in different programming languages.
We want to emphasize this specific definition since it is the crux of the whole concept. And as we move along, it will come together by the time we finish this book.