Low-level design – Timeline Service

Timeline Service is responsible for generating and serving user timelines in the Twitter-like service. It aggregates tweets from the users a person follows and presents them in chronological order. Let’s explore the low-level design of Timeline Service. We have already seen in Figure 11.2 how Tweet Service posts the incoming tweet to Timeline Service via a message queue (Kafka).

Timeline Service will expose the following API endpoints:

• GET /timeline/{userId} – retrieve the user’s home timeline:
• Request: User authentication token
• Response: List of tweet objects representing the user’s timeline

• GET /timeline/{userId}/mentions – retrieve the user’s mentions timeline:
  • Request: User authentication token
  • Response: List of tweet objects mentioning the user

Given that we have the API endpoints listed, we will now check the data flow.

Data flow

Timeline Service relies...