Event-driven architecture (EDA) is a loosely coupled, distributed architecture that collects events from applications, processes them in real time, and routes them to downstream systems without waiting for a response. EventBridge enables you to build EDA solutions of any complexity by connecting cloud products, applications, and services through the CloudEvents 1.0 protocol.
Key concepts
An *event* is a record of a state change, such as a new order placed or an order status updated to reflect a return.
In EDA, three roles interact:
Event producers generate events across applications.
Event router (EventBridge) receives, filters, and delivers those events.
Event consumers (downstream products and services) react to delivered events.
Because producers and consumers communicate only through the router, each side can evolve, scale, and fail independently.
Core capabilities
EventBridge provides three core capabilities:
| Capability | What it does |
|---|---|
| Event collection | Captures events generated across applications, such as new order creation or changes in order status, including returns and exchanges |
| Event processing | Sanitizes, filters, and validates events |
| Event routing | Analyzes event content and delivers events to downstream products |
Advantages
Loose coupling
Reduces dependencies between event producers and consumers. Producers focus solely on generating events and do not need to know how events are processed or which consumers receive them. A failure in one component does not affect other services.
Asynchronous execution
EDA supports asynchronous scenarios. During peak demand, events from various sources are collected and stored in the event bus, then gradually distributed. This prevents system congestion and resource overload.
Scalability
Routing and filtering capabilities support service partitioning, making it straightforward to scale and distribute routes. You can add new consumers without modifying producers.
Agility
EventBridge integrates with multiple Alibaba Cloud products and applications, supporting routing events to any system service for fast, efficient deployment.
How it works
HR onboarding example
The following diagram shows an EDA for a human resources (HR) service system. EventBridge collects new employee onboarding events from the HR system and routes them to the appropriate downstream services. This architecture improves site scalability and simplifies enterprise architecture upgrades and system extensions.
Order service example
In this architecture, EventBridge collects events for various order statuses and distributes them to target services.
