Busting Synapse and WSO2 ESB Myths

Paul Fremantle, PMC chair of the Apache Synapse project and CTO of WSO2, has written a very interesting blog post addressing some of the myths concerning Apache Synapse and WSO2 ESB. As of now both projects are quite popular, mature and have a very large user base including some of the largest organizations in the world. Surprisingly there are still some people who believe that these projects do not fall under the category of ESB (Enterprise Service Bus) implementations. In his latest post, Paul gives a clear and complete answer to all these misbeliefs, and backs it up with a wide range of facts.

ESB is one of those things in the IT world which don't have a proper standard definition. The best definitions I've come across attempt to align the term along the following cues:

• An architectural construct that provides fundamental services to complex architectures
• An entity that acts as a hub connecting many diverse systems
• A central driver that facilitates Enterprise Application Integration (EAI)

Apache Synapse and WSO2 ESB pass with flying colors on all the above criteria. They provide an array of fundamental services to the systems and architectures that rely on them.  Some of these basic services are:

• Message passing, routing and filtering
• Message transformation
• Protocol conversion
• QoS enforcement (security, reliable delivery etc)
• Logging, auditing and monitoring

Because Synapse and WSO2 ESB do such a good job providing these fundamental services, they can be used to integrate a large number of heterogeneous systems in an enterprise setting. As Paul has also pointed out in his post, Synapse and WSO2 ESB are currently used in hundreds of production deployments all around the world to connect various applications, implemented using various technologies (both open source and proprietary) running on various platforms (Windows, Linux, .NET, J2EE, LAMP, cloud..you name it). In other words Synapse and WSO2 ESB are widely used as centralized drivers that facilitate EAI. The configuration model of Synapse and WSO2 ESB is so agile and powerful that practically any EAI pattern can be implemented on top of them. In fact there are tons of samples, articles and tutorials that explain how various well-known EAI patterns can be implemented using these 'ESB implementations'.

One thing that I've learnt from writing code to Synapse is that it has a very flexible enterprise messaging model. Support for any wire level protocol or any message format can be easily implemented on top of this model and can be deployed as a separate pluggable module. During the last few years, I myself have contributed to the implementation of following adapters/connectors on various occasions:

• FIX transport
• SAP transport (IDoc and BAPI support)
• MLLP transport and HL7 message formats
• CSV and various other office document formats
• Thrift connector
• Numerous other custom binary protocols based on TCP/IP

This is just a bunch of stuff that I've had the privilege of implementing for Synapse/WSO2 ESB. I know for a fact that other committers of Synapse and WSO2 ESB have been working on supporting dozens of other protocols, message formats and mediators. Thanks to all this hard work Synapse and WSO2 ESB are currently two of the most powerful and feature-complete ESB implementations anyone will ever come across. Also the existence of connectors for so many protocols and applications is a testament to the agility and flexibility that Synapse and WSO2 ESB can bring in as ESB products.

Another aspect of Synapse/WSO2 ESB that has been questioned many times is their ability to support RESTful integrations (Paul also addresses this issue in his post). This confusion stems from the fact that Synapse uses SOAP as its intermediary message format. Without going into too many technical details, I'd just like to point out that one of the largest online marketplace and auctioning providers in the world uses Synapse/WSO2 ESB to process several hundred millions of REST calls in a daily basis. The new API support we have implemented in Synapse makes it absolutely simple to design, implement and expose RESTful APIs on Synapse/WSO2 ESB. In fact I recently published an article which demonstrates through practical examples how powerful RESTful applications can be implemented using Synapse/WSO2 ESB while supporting advanced REST semantics such as HATEOAS. The recently released WSO2 API Manager product which supports exposing rich web APIs with support for API key management is also based on Synapse/WSO2 ESB.

I think I have made my point. Both Synapse and WSO2 ESB are two excellent ESB choices if you're looking to adopt SOA or enterprise integration within your organization. Their wide range of features is only second to the very high level of performance they offer in terms of high throughput and low resource utilization. Please also go through the post made by Paul, where he has explained some of the above issues with low level technical details. I particularly like his analogy concerning Heisenberg's principle of uncertainty :) 

How to GET a Cup of Coffee the WSO2 Way: An Article

Since we implemented REST API support for WSO2 ESB (and Apache Synapse), we have received many requests for new samples, articles and tutorials explaining this powerful feature. I started working on an end-to-end sample for API support somewhere around March but didn't have enough cycles to write it up. Finally, after a several months delay, I was able to submit the finalized sample and the article to WSO2 Oxygen Tank last month. Now it has been published and available for reading on-line at http://wso2.org/library/articles/2012/09/get-cup-coffee-wso2-way

This articles starts with a quick overview on the REST support provided by WSO2 platform. It describes the API mediation capability of the ESB in detail providing several examples. Then the article explains how a complete order management system can be constructed using the REST support available in WSO2 ESB. This sample application has been inspired by the popular article on RESTful application development titled "How to GET a Cup of Coffee" by Jim Webber. Webber's article describes a hypothetical application used in a Starbucks coffee shop which supports placing orders, making payments, and processing orders. The sample described in my article implements all the major interfaces and message flows outlined by Webber. I have also made all the source code and configurations available so that anybody can do the same on their own machines using WSO2 middleware. To make it even more interesting I also implemented a couple of user interfaces for Webber's Starbucks application. These UI tools are also described in my article and they can help you better understand how the applications communicate with each other using RESTful API calls and how their application states change according to typical HATEOAS principles.

Towards the latter part of the article I discuss some of the advanced features of RESTful application development and how such features can be implemented on top of WSO2 middleware. This includes some very important topics such as security, caching and content negotiation.

I hope you will find this article interesting and useful. As always feel free to send any feedback either directly to me or to dev@wso2.org.

Turning Over a New Leaf

Last month I said good bye to a fantastic career at WSO2. I joined WSO2 on April 2009 as a Software Engineer and worked my way up the ladder to become a Senior Technical Lead. Most of my time at WSO2 was spent on WSO2 ESB, WSO2's flagship product. I also contributed to Carbon, the core platform on which all WSO2 products are built, and also implemented a number of cross cutting features which are currently used in multiple WSO2 product offerings. Towards the latter part of my WSO2 career I was mostly working on improving the REST support in WSO2 platform and implementing the WSO2 API Manager product. The WSO2 API Manager 1.0 release that went out in early August marked the end of my career at WSO2 (at least for the next few years).

My time at WSO2 has been a great learning experience. I learned and mastered  a variety of technologies like Web Services, SOA, cloud computing and API management. I got to travel to many countries and had the privilege of  meeting and working with some of the largest IT organizations in the world. Above all I had a lot of fun working with the team WSO2. It's truly a great organization with some of the smartest and coolest people I've ever had the privilege of working with.

This month I'm starting my Computer Science graduate studies at University of California, Santa Barbara. I'll be doing distributed systems research with prof. Chandra Krintz at UCSB Mayhem lab and RACE lab. Popular open source cloud platforms like Eucalyptus and AppScale were originally designed and developed in these labs, and so currently I'm spending some time on getting up to speed on these platforms. You will see me blogging about these technologies time to time over the next few days. Wish me luck :)