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Derek Comartin

Message Ordering in Pub/Sub or Queues

Do you need message ordering? Processing messages in order as they were sent/published to a queue or topic sounds simple but has some implications. What happens when processing a message fails? What happens to all subsequent messages? How is throughput handled when using the competing consumers’ pattern, which loses the guarantee processing in order. Lastly, is ordering even important? YouTube Check out my YouTube channel where I post all kinds of content that accompanies my posts including this video showing everything in this post. Message Ordering What are some reasons that most people think they need to process messages in a particular… Read More »Message Ordering in Pub/Sub or Queues

Commands & Events: What’s the difference?

One of the building blocks of messaging is, you guessed it, messages! But there are different kinds of messages: Commands and Events. So what’s the difference? Well, they have very distinct purposes, usage, naming, ownership, and more! YouTube Check out my YouTube channel where I post all kinds of content that accompanies my posts including this video showing everything in this post. Commands The purpose of commands is the intent to invoke behavior. When you want something to happen within your system, you send a command. There is some type of capability your service provides and you need a way to expose… Read More »Commands & Events: What’s the difference?

Microservices gets it WRONG defining Service Boundaries

Logical boundaries aren’t physical boundaries. A service boundary can be a one-to-one mapping of logical boundary and physical boundary but they don’t have to be. A logical boundary can have many physical boundaries and a physical boundary can be composed of many components from many logical boundaries. Do we have microservices to thank for the idea that the physical, development, and logical views are the same? This introduces a pile of unneeded complexity related to deployment, versioning, and data duplication. YouTube Check out my YouTube channel where I post all kinds of content that accompanies my posts including this video showing everything… Read More »Microservices gets it WRONG defining Service Boundaries