Architecture Patterns with Python

The components of our architecture and what they all do: - Entity: A domain object whose attributes may change but that has a recognizable identity over time. - Value object: An immutable domain object whose attributes entirely define it. It is fungible with other identical objects. - Aggregate: Cluster of associated objects that we treat as a unit for the purpose of data changes. Defines and enforces a consistency boundary. - Event: Represents something that happened. - Command: Represents a job the system should perform. - Service Layer: Defines the jobs the system should perform and orchestrates different components. - Handler: Receives a command or an event and performs what needs to happen. - Unit of work: Abstraction around data integrity. Each unit of work represents an atomic update. Makes repositories available. Tracks new events on retrieved aggregates. - Message bus (internal): Handles commands and events by routing them to the appropriate handler. - Adapters (Secondary): Concrete implementations of an interface that goes from our system to the outside world (I/O). - Repository: Abstraction around persistent storage. Each aggregate has its own repository. - Event publisher: Pushes events onto the external message bus. - Entrypoints (Primary adapters): Translate external inputs into calls into the service layer. - Web: Receives web requests and translates them into commands, passing them to the internal message bus. - Event consumer: Reads events from the external message bus and translates them into commands, passing them to the internal message bus. - N/A External message bus (message broker): A piece of infrastructure that different services use to intercommunicate, via events.