Microsoft BizTalk ESB Toolkit 2.1: Discover innovative ways to solve your mission-critical integration problems with the ESB Toolkit

In most cases, a business process is all about how information travels through the process and how it is handled along the way, and thus the ESB model predicates the integration of such business processes in terms of the five basic steps that conform to the VETRO pattern:

The ESB receives messages from the systems connected to it and performs one or more of the steps mentioned previously. All those steps that define how a message needs to be handled by the ESB are defined as itineraries, that are a set of decoupled processing steps that doesn't necessarily know about the whole process the message just went through or is going to go through afterwards, but they just know what they have to do with the message they just received for processing.

This doesn't sound like rocket science or anything very new, but what the ESB adds to the pattern is the means to make all these stages along the process as decoupled and configurable as possible, so once a process is in place any further changes can be made with the smaller effort and the smallest impact possible on existing systems.

An ESB has different features and capabilities that support one or many of the elements of the VETRO pattern.

The main capabilities that support this model in the ESB are listed in the following table:

If you have been working with BizTalk Server for some time or have some basic knowledge about its architecture and features, you will find that most of those cover these capabilities any ESB system is required to have, but you will also appreciate that some of them could be implemented in different ways, requiring some extra effort from your architecture team to decide the best way of doing so.

Here is where the ESB Toolkit comes to help. Based on the years of experience of architects and IT teams building integrations solutions with BizTalk, these patterns and capabilities have been packaged as a set of guidelines and re-usable components that will help you to build an ESB solution with a more predictable and efficient result.

As we saw in the previous section, ESB is an architectural model that can bring huge benefits to the integration architecture of a company, but there would be potentially many ways to achieve the same goal.

Around 2007, a group of talented architects and developers from the Microsoft BizTalk product group and the Patterns and Practices team came up with the idea of the ESB Guidance, as a set of architectural guidelines and re-usable components that would help us to build an ESB based in Microsoft BizTalk Server 2006 R2. This ESB Guidance was renamed later on to ESB Toolkit with its 2.0 version along with BizTalk 2009. The latest versions of it are the 2.1 that came with BizTalk 2010 (the one that we will cover in this book) and the latest one (2.2) that comes with BizTalk 2013.

Most of the current technologies and IT development platforms nowadays provide huge flexibility and power in terms of implementing solutions, but that flexibility and power sometimes make it difficult to know the better way to implement some common patterns.

In the old days of .NET, we all needed to implement common patterns such as aspect oriented programming, error handling libraries, logging, and so on, and there were teams around the world implementing the same things on and on, each of them on their own flavor. But then the Enterprise Library came along to make our life a bit easier.

The ESB Toolkit is to BizTalk the same as the Enterprise Library is to any .NET application. It just helps to implement common architectural and development practices in a reliable and proven way. Whether you are building an ESB or not, some of the ESB Toolkit principles and re-usable components will be really useful to build high quality BizTalk solutions.

The aim of the ESB Toolkit is to cover all of the capabilities required by a proper ESB by leveraging existing features in BizTalk Server, introducing new re-usable components and documenting it all together so we don't get lost along the way.

We can map the main ESB capabilities we listed in previous sections to the BizTalk and ESB Toolkit features like:

As we mentioned earlier, all these capabilities are pretty much required to build a full-blown ESB architecture and they should be interoperable and decoupled enough to provide the flexibility and scalability that we need.

All this can be very well represented with the representation of the ESB Toolkit architecture and main components shown in the following figure.

Exception Management framework is a set of components and APIs that provide a standardized approach to handle, notify, and process any exceptional situations that might occur during the processing of a message. It's pretty much like the counterpart of the exception handling in the Enterprise Library.

We will dedicate a whole chapter to this topic later on in this book.