Implementation of Event-Driven Architecture(EDA)

Implementing Event-Driven Architecture (EDA) involves several components, including event sources, an event bus, and subscribers. Here, we will implement a simplified example using Python and a basic event handling mechanism.

Let’s consider a scenario of an online ordering system where we want to notify users when their order is placed. We’ll implement a simple EDA system with a publisher, an event bus, and a subscriber.

Below is the implementation of the above example:

Python

# Event Bus
class EventBus:
    subscribers = {}

    @classmethod
    def subscribe(cls, event_type, subscriber):
        if event_type not in cls.subscribers:
            cls.subscribers[event_type] = []
        cls.subscribers[event_type].append(subscriber)

    @classmethod
    def publish(cls, event_type, data=None):
        if event_type in cls.subscribers:
            for subscriber in cls.subscribers[event_type]:
                subscriber.handle_event(event_type, data)


# Event Subscriber
class OrderNotificationSubscriber:
    def handle_event(self, event_type, data=None):
        if event_type == 'OrderPlaced':
            print(&quot;Notification: Your order with ID {} has been placed!&quot;.format(data['order_id']))


# Event Publisher
class OrderService:
    def place_order(self, order_id):
        # Order placement logic here
        # ...

        # Notify subscribers about the order placement
        EventBus.publish('OrderPlaced', {'order_id': order_id})


# Example Usage
if __name__ == &quot;__main__&quot;:
    # Creating instances
    order_notification_subscriber = OrderNotificationSubscriber()
    order_service = OrderService()

    # Subscribing the subscriber to the 'OrderPlaced' event
    EventBus.subscribe('OrderPlaced', order_notification_subscriber)

    # Placing an order
    order_service.place_order(order_id=123)

Output

Notification: Your order with ID 123 has been placed!

Below is the explanation of the above code:

Event Bus:
- The EventBus class serves as a central hub for handling events. It allows components to subscribe to specific event types and publishes events to notify subscribers.
Event Subscriber:
- The OrderNotificationSubscriber class is an example subscriber that handles the ‘OrderPlaced’ event. In a real-world scenario, this subscriber could trigger notifications, emails, or other actions.
Event Publisher:
- The OrderService class represents a service responsible for placing orders. After placing an order, it uses the EventBus to publish the ‘OrderPlaced’ event, notifying subscribers.
Example Usage:
- In the example usage section, we create instances of the subscriber and publisher. The subscriber subscribes to the ‘OrderPlaced’ event using the EventBus.subscribe method. When an order is placed using order_service.place_order, the event is published, and the subscriber’s handle_event method is called.

Event-Driven Architecture – System Design

Event-driven architecture (EDA) is a design pattern where system components communicate by generating, detecting, and responding to events. Events represent significant occurrences, such as user actions or changes in the system state. In EDA, components are decoupled, allowing them to operate independently. When an event occurs, a message is sent, triggering the appropriate response in other components. This fosters flexibility, scalability, and real-time responsiveness in systems.

For example:

In a big party where everyone is doing their own thing. Instead of constantly checking on each other, they use a bell to signal important things, like “cake’s ready” or “dance party starting.” That bell is like an “event” in event-driven architecture.

In the tech world, different parts of a computer system communicate by sending messages when something important happens. Each part can focus on its job, and when it needs attention, it rings the bell (sends an event).

Important Topics for the Event-Driven Architecture

Importance of Event-Driven Architecture(EDA) in System Design
Events in Event-Driven Architecture(EDA)
Events Types in Event-Driven Architecture(EDA)
Components of Event-Driven Architecture(EDA)
Benefits of Event-Driven Architecture(EDA)
Drawbacks of Event-Driven Architecture(EDA)
Use Cases of Event-Driven Architecture(EDA)
Implementation of Event-Driven Architecture(EDA)
Event-Driven vs. Message Driven Architecture

Implementation of Event-Driven Architecture(EDA)

Event-Driven Architecture – System Design

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Implementation of Event-Driven Architecture(EDA)

Event-Driven Architecture – System Design

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