Gregor’s Ramblings on Conversations - Enterprise Integration Patterns

This blog chronicles my journey with asynchronous and distributed system design over two decades. These are my Ramblings related to Conversations [See all Ramblings]. Subscribe to my ramblings via RSS.

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Discussing the Google cloud Pub/Sub system in the last rambling reminded me that the Publish-subscribe Channel pattern makes for a good example of the subtle but important difference between Messaging Patterns and Conversation Patterns. This comparison is timely as I picked up documenting Conversation Patterns again. Read more »

As indicated a good while ago I spent some time thinking about patterns that instead of following a message through multiple systems, looks at the message exchange over time between a (mostly) fixed set of systems. I call these message exchanges "conversations". Sadly my writing efforts on Conversation Patterns fell very much asleep around 2008, partly due to my fear that with the rise of REST, stateful conversations between systems would step into the background as most integration problems are now solved with a simple POST or GET. A presentation and conversation at Frank Leymann's IaaS PhD Seminar enlightened me that this is not at all true: systems following the REST architectural style very much engage in conversations. Read more »

The beginning of a New Year is the time to reflect on the past and make resolutions for the future. It's become my tradition to kick off the year with some reflection on EIP, so here we go. Read more »

I am just returning from a trip to Montreal and Keystone, CO for the OOPSLA and Colorado Software Summit conferences. I spoke on SOA Patterns, workshopped my conversation pattern paper, and gave six talks on event-driven architectures and building mashups using Yahoo! Pipes and Google Mashup Editor. Phew! Read more »

I just returned from a trip to Germany to attend a workshop on The Role of Business Processes in Service Oriented Architecture. Besides a guaranteed top score in buzzword bingo the workshop provided a unique opportunity to connect thought leaders from academia and industry over the course of a week. The attendee roster sported the usual industry heavyweights, i.e., Microsoft, IBM, SAP, making me proud to add Google to the list. Read more »

On a recent project we developed a Web services framework that supports asynchronous callbacks and asynchronous invocation with polling. The difficulties we had describing what we were trying to do to my fellow ThoughtWorkers on other projects prompted me to discuss the different forms of asynchrony in a little more detail. Read more »

People often criticize asynchronous messaging solutions as too complicated and cumbersome. Or, they believe distributed solutions cannot be successful unless they include a distributed transaction model. There is little doubt that asynchronous solutions require us to think in new ways as we have to deal with concurrency, out-of-sequence issues, correlation and other. However, the real world is full of examples of asynchronous processes that deal successfully with exactly the same issues. We don't have to go further than the local coffee shop... Read more »

When using asynchronous messaging, we can no longer rely on the linear, in-sequence execution of events. Therefore, the notion of correlating multiple messages is fundamental to designing robust messaging solutions. While correlation seems to be a simple concept at first glance, there are quite a few interesting nuances. Read more »