Works such as Gregor Hohpe's Enterprise Integration Patterns describe the building blocks that allow us to send a message between two components. But components often exchange more than just a single message with their collaborators - that is they hold a conversation. Understanding how to build components that can hold successful conversations is the key to unlocking the power of event driven architectures - but too often we focus on just the single exchange.

Drawing on the works of Hohpe, Helland and others we talk about building blocks such as correlation ids, conversation ids and activities (including a discussion of outboxes and inboxes). With those we will talk about the basic conversational patterns: monolog patterns such as fire and forget and publish and subscribe and dialog patterns such as request-response and request-response. We will identify how ideas like Event Carried State Transfer are an important part of how we have conversations. We will cover how we deal with errors, such as tentative operations, retry or compensating actions. Finally we will look into macro scale conversational patterns such as choreography and orchestration.

During this session we will also talk about messages vs events and related issues such as causality.