Event-driven architecture decouples producers and consumers. Loosely coupled, scalable, resilient systems.
Publish/Subscribe Pattern¶
Event-Driven Programming¶
class EventBus: def __init__(self): self.handlers = {} def subscribe(self, event_type, handler): self.handlers.setdefault(event_type, []).append(handler) def publish(self, event_type, data): for handler in self.handlers.get(event_type, []): handler(data) bus = EventBus() bus.subscribe(‘user.created’, send_welcome_email) bus.subscribe(‘user.created’, create_default_settings) bus.publish(‘user.created’, {‘id’: 1, ‘email’: ‘[email protected]’})
Kafka¶
Producer¶
from kafka import KafkaProducer producer = KafkaProducer(bootstrap_servers=’localhost:9092’) producer.send(‘events’, json.dumps({‘type’: ‘order.created’, ‘data’: {…}}).encode())
Consumer¶
from kafka import KafkaConsumer consumer = KafkaConsumer(‘events’, bootstrap_servers=’localhost:9092’) for message in consumer: event = json.loads(message.value) handle_event(event)
Key Takeaway¶
Events for loosely coupled systems. Kafka for high-throughput, RabbitMQ for complex routing.