cqrs and event sourcing on Windows Azure
•Download as PPTX, PDF•
0 likes•325 views
This document discusses CQRS and event sourcing on Windows Azure. It defines event sourcing as storing all changes to application state as a sequence of events. It demonstrates how to design a CQRS model using aggregates, events, projections and commands. It shows the anatomy of a stored event and demonstrates appending events to an Azure-based event stream. It discusses hosting the full CQRS/event sourcing model on Azure and provides next steps to experiment further.
Recommended
More Related Content
More from Duncan Jones
More from Duncan Jones (18)
cqrs and event sourcing on Windows Azure
- 1. CQRS AND EVENT SOURCING ON WINDOWS AZURE Duncan Jones 💬 @Merrion
- 3. NOTES
- 4. DEFINITION OF EVENT SOURCING
- 5. DESIGNING THE BUSINESS MODEL Event storming Domain Driven Design UX Driven Design
- 6. DEMO #1 – CQRS DESIGNER Aggregates •Top level “things” Events •What can happen to them Projections •What we can derive about an aggregate Queries •What we can derive about many aggregates Commands •How we cause changes to occur
- 7. ANATOMY OF A STORED EVENT
- 8. DEMO #2 – AZURE BASED EVENT STREAM Create Append Run Projection
- 9. HOSTING THE CQRS/ES MODEL ON AZURE
Editor's Notes
- From WTF to WHY to WOW describes my own journey with event sourcing Due to limitations in CRUD architecture when dealing with read-write deadlocks when very large price updates occured
- The agenda is that I will do a quick “props based, no computer” show and tell to describe what event sourcing is, then discuss how it compares to a traditional database (RDBMS) then finish with some advice on how to get up to speed and start using event sourcing yourselves.
- There won’t be any specific programming language used This discussion is aimed at the beginner (level 101) but there may be intermediate level discussion on the actual implementation technology
- So first I am going to show how a database stores data (using the whiteboard) and then will show how the same data would be stored in an event sourcing data model (also referred to as event streaming). The business domain I’ll use is a very, very simplified bank account system.
- The way an event is stored keeps the event content (that is used in projection logic) separate from its context and identity which is not “business meaningful”.
- For this demo I will just step through a unit test that appends a stack of events to an event stream stored on Azure AppendBlob storage and run a projection over it that includes caching.
- Choosing the best backing technology – it is worth experimenting but this image gives a broad brush strokes idea of the best technology fit
- Next steps:- The best advice I can give you in terms of learning event sourcing (and this also applies to CQRS) is to experiment with it – either in a personal project or in a new build work project that allows for some flexibility. If you want an out-of-the-box experience there is a project called “Event Store” at the URL geteventstore.com that you should give a go. There are videos on YouTube – especially the “Goto 2014;” talk by Greg Young, a number of blogs by people like Daniel Whittaker and Dino Esposito and a good few folks on twitter discussing this (including myself) and the book “Event Centric: Finding Simplicity in Complex Systems” (also by Greg Young) If you are a .NET developer there are two linked projects I am working on (hosted on CodeProject) – a CQRS / Event Sourcing framework that runs on top of Azure storage and a graphical designer for creating the event source based business model. Neither is production ready quite yet but getting there.