Web Services are poised to do for program-to-program interactions. Web Services allow companies to reduce the cost of doing e-business, deploy solutions faster, and open up new opportunities. The key to reaching this new horizon is a common program-to-program communications model, built on existing and emerging standards such as HTTP, Extensible Markup Language (XML), Simple Object Access Protocol (SOAP), Web Services Description Language (WSDL), and Universal Description, Discovery and Integration (UDDI). Web Services allow applications to be integrated more rapidly, easily, and less expensively than ever before. Integration occurs at a higher level in the protocol stack, based on messages centered more on service semantics and less on network protocol semantics, thus enabling loose integration of business functions. These characteristics are ideal for connecting business functions across the Web, between enterprises, and within enterprises. They provide a unifying programming model so that application integration inside and outside the enterprise can be done with a common approach, leveraging a common infrastructure.
Web Service is a way to expose the functionality of an application to other applications, without a user interface. It is a service that exposes an API over HTTP. Web Services allow applications developed in different technologies to communicate with each other through a common format like XML, JSON and etc. Web services are not tied to anyone’s operating system or programming language. For example, an application developed in Java can communicate with the one developed in C#, Android, etc., and vice versa. Web Service is a connection technology, a way to connect services together into a Service Oriented Architecture (SOA).
Microservice is an independently deployable service modeled around a business domain. It is a method of breaking large software applications into loosely coupled modules, in which each service runs a unique process and communicates through APIs. It can be developed using messaging or event-driven APIs or using non-HTTP backed RPC mechanisms. Micro Services are designed to cope with the failure and breakdowns of large applications. Since multiple unique services are communicating together, it may happen that a particular service fails, but the overall larger applications remain unaffected by the failure of a single module.
Let us understand these concepts with the help of an example of an Online Shopping Website Application.
In figure-1: The Online Shopping Web Application is developed in Monolithic Architecture. In this application, there is one Web Service which communicates with web application and database. So this web service might be performing many functional tasks related to database operations.
In figure-2: The Online Shopping Web Application is developed in Micro Services Architecture. All the components of the web application are developed independently, single functional responsible, fine-grained clearly scoped services.
Web Services could be of any size, including large enterprise apps retrofitted with APIs that too many other apps depended on. Although “micro” in Micro Services, the basic concept is that each service performs a single function. For example, one of the largest e-commerce portals, Amazon, has migrated to Micro Services. They get countless calls from a variety of applications, including applications that manage the Web Services API as well as the portal, which would have been simply impossible to handle for their old, two-tiered architecture.
A Web Service is a service offered by an application to another application, communicating with each other via the World Wide Web (WWW).
The Web Service typically provides an object-oriented web-based interface to a database server, utilized by another web server, or by a mobile application, that provides a user interface to the end-user. Another common application offered to the end-user may be a mash-up, where a web server consumes several web services at different machines and compiles the content into one user interface.
Applications built as Microservices can be broken into multiple component services and this service can be a Web Service, which should run the unique process and then redeployed independently without compromising the integrity of an application.
Microservices style is usually organized around business capabilities and priorities. Unlike a traditional monolithic development approach, where different teams have a specific focus on, say, UIs, databases, technology layers, or server-side logic, Microservices architecture utilizes cross-functional teams. The responsibilities of each team are to make specific products based on one or more individual services communicating via message bus. It means that when changes are required, there won’t necessarily be any reason for the project, as a whole, to take more time or for developers to have to wait for budgetary approval before individual services can be improved. Most development methods focus on projects: a piece of code that has to offer some predefined business value must be handed over to the client and is then periodically maintained by a team. But in Micro Services, a team owns the product for its lifetime.
In a monolithic service-oriented architecture deployment, each small change meant that the entire monolith needed to be rebuilt, and this, in turn, meant that re-builds weren’t happening as rapidly as they should.