Events

Events represent the sequence of state-changing events allowing for a comprehensive history of state transformations, easy debugging, and complex business logic support.

• Auditability: Records every change, ensuring full traceability.
• Replayability: Enables state reconstruction, aiding in debugging and analysis.
• Scalability: Efficiently manages high loads through decoupling.
• Resilience: Recovers state post-failure from the event log.
• Insightful Data: Offers deep insights through historical analysis.
• Real-World Alignment: Domain events mirror real-life business processes.

Creating Events

Events should be the representation of real domain events. You should define them by talking to a domain expert or using techniques like event storming. In our banking example, an event could be a deposit or a withdrawal.

Because events will be stored in a database, they should be serializable. In Rust, you can use the serde crate to derive the Serialize and Deserialize traits.

use serde::{Deserialize, Serialize};
 
use crate::todolist_scalar::{TaskIndex, TaskName};
 
#[derive(Clone, Debug, Serialize, Deserialize)]
pub enum TodoListEvent {
    TaskAdded(TaskIndex, TaskName),
    TaskRemoved(TaskIndex),
    TaskCompleted(TaskIndex),
}