What is event-driven architecture in serverless computing?

Key takeaways:

• EDA promotes asynchronous communication, while server-less computing provides on-demand resources, leading to highly efficient and responsive applications.

• EDA offers decoupling, scalability, efficiency, and reactivity. These benefits make EDA an attractive choice for modern application development.

• Event routing, error handling, and observability are essential to ensure successful implementation.

Serverless computing lets developers focus on writing application code without worrying about servers. Event-driven architecture (EDA) is a way to design applications where services talk to each other using events, like signals. We can combine these paradigms to build robust, fast, and cost-efficient applications.

Event-driven architecture

Event-driven architecture has become increasingly popular, as has its number of its applications. Before we proceed, let’s understand what event-driven means.

• At its core, event-driven architecture is a software design pattern where components communicate asynchronously through events.

• An event signals that something significant has happened, such as a file being uploaded, a database being updated, or a user being logged in.

• Components in an EDA can be event producers (generating events) or event consumers (reacting to events).

Serverless computing is a cloud computing execution model where the cloud provider fully manages the allocation and provisioning of servers. Serverless functions automatically scale up to handle bursts of requests and scale down to zero when not in use. With serverless functions, it makes sense for our applications to be “triggered” by useful events instead of running all the time, waiting for requests.

EDA in serverless computing

As stated above, in serverless computing, the primary benefit is auto-scaling. EDA can nurture this behavior with events. Events can invoke servers to become active and deal with the event. Different servers (serverless functions) can be activated based on the nature of the event. Let’s look at a practical example below:

1. Customer places order: A customer submits an order on an e-commerce website.

2. Order event: The order placement generates an “order created” event.

3. Event router: The event is sent to a central event router or event bus (e.g., Amazon EventBridge, Azure Event Grid).

4. Parallel processing: Multiple serverless functions are triggered in parallel:

   1. Inventory check function: A function checks if the ordered items are in stock.

   2. Payment processing function: A function processes the customer’s payment.

   3. Fraud detection function: A function analyzes the order for potential fraud.

5. Order Confirmation: A final serverless function gathers results from previous steps and sends an order confirmation email to the customer.

Using EDA with serverless computing offers several features:

• Decoupling: EDA allows for loose coupling between components, a key strength of serverless functions. Each function acts independently, reacting to specific events.

• Scalability: Serverless functions scale automatically based on demand. EDA’s asynchronous nature complements this, allowing the system to handle bursts of events efficiently.

• Efficiency: With serverless, you only pay when functions are running. EDA prevents idle waiting; functions are triggered only when necessary.

• Reactivity: EDA lets applications respond to events in real time, which is crucial for use cases like real-time data processing or user interactions.

Common use cases

EDA and serverless computing are relatively new terms in the software field. But as time goes on, new applications are being discovered that can greatly benefit from them.

• Data processing pipelines: Files uploaded to storage can trigger serverless functions for image resizing, video transcoding, etc.

• Microservices communication: Services in a microservices architecture can communicate via events without requiring direct, synchronous calls.

• IoT applications: Events from sensors and devices can trigger real-time actions or analysis.

Key considerations

As with anything in computing, EDA in serverless computing comes with a few cautionary steps that must be taken to ensure the effectiveness of their application:

• Event routing: Choose a robust event routing mechanism (e.g., Amazon EventBridge, AWS SNS, Azure Event Grid)

• Error handling: Design for event-driven failures and implement retry mechanisms.

• Observability: Monitor the flow of events in your system for debugging and optimization.

Note: With EDA and serverless, failures become less catastrophic. If an event doesn't get processed, you can easily retry, while the rest of your system is unaware and functioning normally.

Test yourself

Before moving on to the conclusion, test your understanding:

Conclusion

Event-driven architecture and serverless computing create a powerful combination, promoting scalability, efficiency, and agility. If you’re building on serverless, understanding and employing EDA can unlock tremendous benefits for your applications.