Component

The Building Block of Event-Driven Microservices

A RECQ component is a self-contained unit of software that implements a well-defined set of functionalities within a RECQ-based application. It plays a crucial role in promoting modularity, loose coupling, and asynchronous communication within the system.

Properties of a RECQ Component:

• Isolation:

  • Temporal Isolation: Components operate independently and asynchronously without relying on other components to be available at any specific time.

  • Spatial Isolation: Components don't need knowledge about the location or existence of other components in the system. This concept is also known as Location Transparency.

• Containment:

  • Components encapsulate the logic and resources they need to fulfill their responsibilities.

  • This aligns with the concept of aggregation in Domain-Driven Design, where tightly coupled entities are grouped together within a component.

• Delegation:

  • Components focus on a well-defined set of tasks and delegate any unrelated functionalities to other components or external services.

Capabilities of a RECQ Component:

• Message Handling:

  • Components can receive messages addressed specifically to them.

  • They can process the message and optionally respond with a reply message to the sender.

  • This capability allows components to implement reactive behaviour and respond to external actions.

• Internal State Management:

  • Components can maintain a persistent internal state that reflects their specific data and information relevant to their functionalities.

• Event-Driven Communication:

  • Components can publish System State Change Events whenever their internal state changes due to processing a message.

  • Publishing events allows other components to be notified about these changes and potentially update their own state accordingly.

  • Components can also subscribe to specific System State Change Events published by other components.

  • By consuming events, components can react asynchronously to changes in the system without needing direct communication with the originating component.

• Messaging Other Components:

  • Components can send messages to other components within the system.

  • This capability allows for inter-component communication to coordinate activities and share information.

• Replicability:

  • A RECQ component can be replicated across multiple instances to achieve horizontal scaling.

  • The design of the component should ensure consistency even with multiple instances operating concurrently.

Strict definition:

• Can receive messages and may respond to them

• Can manage a persistent internal state

• Can publish events

• Can subscribe to events

• Can send messages

• Must be replicable

Benefits of RECQ Components:

• Modularity: Breaking down the application into independent components improves code organization and maintainability.

• Loose Coupling: Asynchronous messaging and event-driven communication reduce dependencies between components, making the system more flexible and adaptable.

• Scalability: Components can be scaled independently based on their specific load requirements.

• Resilience: Event-driven communication and independent components enhance system resilience. If one component fails, others can continue operating based on the events they've received.

Conclusion:

RECQ components are the fundamental building blocks of a RECQ architecture. By adhering to the principles of isolation, containment, and delegation, and leveraging their capabilities effectively, developers can create robust, scalable, and maintainable event-driven microservices applications.