Architectural Patterns

Event-driven messaging

One of the core patterns of event-driven architecture is event-driven messaging; services (publishers) notify their consumers (subscribers) with relevant events when they happen, while customers are not necessarily waiting or aware of that event.

Imagine a stock trading service notifying its users whenever a particular stock price goes up:

The preceding diagram depicts a cycle of notification process kicks in when a stock price hit a particular  threshold; the subscriber lets event manager knows the intention, and the publisher publish (informs) when the event occurs. The $X is the predefined limit or sale price, and ...