Messaging

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

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?

What’s the asynchronous request-response pattern for? We’re used to synchronous communication. You make a request to another service and get a response. When you move to asynchronous communication, you often think of messages as fire-and-forget. You send a command to a queue, and the consumer handles it asynchronously. Because of the temporal decoupling, you don’t know when the message was processed or what the result was. However, there is a solution! Let me explain how you can use the request-response pattern to reply sender once a message is processed. YouTube Check out my YouTube channel where I post all kinds of content… Read More »Asynchronous Request-Response Pattern for Non-Blocking Workflows