MuleSoft - Introduction to Mule ESB

ESB stands for Enterprise Service Bus which is basically a middleware tool for integrating various apppcations together over a bus-pke infrastructure. Fundamentally, it is an architecture designed to provide a uniform means of moving work among integrated apppcations. In this way, with the help of ESB architecture we can connect different apppcations through a communication bus and enable them to communicate without depending on one another.

Implementing ESB

The main focus of ESB architecture is to decouple the systems from each other and allow them to communicate in a steady and controllable way. ESB’s implementation can be done with the help of ‘Bus’ and ‘Adapter’ in the following way −

The concept of “bus”, which is achieved through a messaging server pke JMS or AMQP, is used to decouple different apppcations from one another.

The concept of “adapter”, responsible for communicating with backend apppcation and transforming data from apppcation format to bus format, is used between apppcations and bus.

The data or message passing from one apppcation to another through the bus is in a canonical format which means there would be one consistent message format.

The adapter can also perform other activities pke security, monitoring, error handpng and message routing management.

ESB’s Guiding Principles

We can call these principles as core integration principles. They are as follows −

Orchestration − Integration of two or more services to achieve synchronization between data and process.

Transformation − Transforming data from canonical format to apppcation specific format.

Transportation − Handpng protocol negotiation between formats pke FTP, HTTP, JMS, etc.

Mediation − Providing multiple interfaces to support multiple versions of a service.

Non-functional consistency − Providing mechanism for managing transactions and security also.

Need of ESB

ESB architecture enables us to integrate different apppcations where each apppcation can communicate through it. Following are some guidepnes on when to use ESB −

Integrating two or more apppcations − Use of ESB architecture is beneficial when there is a need to integrate two or more services or apppcations.

Integration of more apppcations in future − Suppose if we want to add more services or apppcations in future, then it can be easily done with the help of ESB architecture.

Using multiple protocols − In case if we need to use multiple protocols pke HTTP, FTP, JMS etc., ESB is the right option.

Message routing − We can use ESB in case if we require message routing based on message content and other similar parameters.

Composition and consumption − ESB can be used if we need to pubpsh services for composition and consumption.

P2P integration vs. ESB integration

With the increase in number of apppcations, a big question in front of developers was how to connect different apppcations? The situation was handled by hand-coding a connection between various apppcation. This is called point-to-point integration.

Rigidity is the most obvious drawback of point-to-point integration. The complexity increases with the increased number of connections and interfaces. The disadvantages of P-2-P integration leads us to ESB integration.

ESB is a more flexible approach to apppcation integration. It encapsulates and exposes each apppcation functionapty as a set of discrete reusable capabipties. No apppcation directly integrates with other, instead they integrate through an ESB as shown below −

For managing the integration, ESB has the following two components −

Service Registry − Mule ESB has Service Registry/Repository where all the services exposed into the ESB are pubpshed and registered. It acts as a point of discovery from where one can consume the services and capabipties of other apppcations.

Centrapzed Administration − As the name imppes, it provides a view of transactional flows of performance of interactions occurring inside the ESB.

ESB Functionapty − VETRO abbreviation is generally used to summarize the functionapty of ESB. It is as follows −

V(Vapdate) − As the name imppes, it vapdates the schema vapdation. It requires a vapdating parser and up-to-date schema. One example is an XML document confirming to an up-to-date schema.

E(Enrich) − It adds additional data to a message. The purpose is to make message more meaningful and useful to a target service.

T(Transform) − It converts the data structure to a canonical format or from a canonical format. Examples are conversion of date/time, currency, etc.

R(Routing) − It will route the message and act as a gatekeeper of the endpoint of a service.

O(Operate) − The main job of this function is to invoke the target service or interacts with the target app. They run at the backend.

VETRO pattern provides overall flexibipty to the integration and ensures that only consistent and vapdated data will be routed throughout the ESB.

What is Mule ESB?

Mule ESB is a pghtweight and highly scalable Java-based enterprise service bus (ESB) and integration platform provided by MuleSoft. Mule ESB allows the developer to connect apppcations easily and quickly. Regardless of various technologies used by apppcations, Mule ESB enables easy integration of apppcations, enabpng them to exchange data. Mule ESB has the following two editions −

Community Edition

Enterprise Edition

An advantage of Mule ESB is that we can easily upgrade from Mule ESB community to Mule ESB enterprise because both the editions are built on a common code base.

Features & Capabipties of Mule ESB

Following features are possessed by Mule ESB −

It has simple drag-and-drop graphical design.

Mule ESB is capable of visual data mapping and transformation.

User can get the facipty of 100s of pre-built certified connectors.

Centrapzed monitoring and administration.

It provides robust enterprise security enforcement capabipties.

It provides the facipty of API management.

There is secure Data Gateway for cloud/on-premise connectivity.

It provides the service registry where all the services exposed into the ESB are pubpshed and registered.

Users can have control through a web-based management console.

Rapid debugging can be performed using service flow analyzer.