Practical Microservices

Making the Message Store Aware of Origin Streams

In code/video-tutorials/src/message-store/subscribe.js we wrote getNextBatchOfMessages which retrieves the batches of messages in the category we’re subscribing to. For subscriptions that have an originStreamName, we’ll further filter that query result based on whether or not the messages have that originStreamName in their metadata.

First the filtering function:

video-tutorials/src/message-store/subscribe.js

const category = require('./category')
function configureCreateSubscription ({ read, readLastMessage, write }) {
  // ...
    function filterOnOriginMatch (messages) { 
      if (!originStreamName) { 
        return messages
      }

      return messages.filter(message => {