Mastering Azure Serverless Computing

The Durable Functions execution state

In the previous sections, you learned about Durable Functions and the types of functions you can use when you create a solution using this technology.

In this section, you will see how Durable Functions manage the state and can orchestrate the activity functions (the execution state).

When you talk about the execution state, you keep in mind three pillars:

• Event sourcing
• Checkpoint
• Replay

The orchestrator functions manage their state using the event sourcing design pattern.

This pattern is based on registering all the events a single Durable Function receives. In this way, every moment a single instance of a Durable Function can rebuild its actual state simply replays the whole set of events received. ...