Eventbridge

In this lesson, we explore AWS EventBridge, a fully managed, serverless event bus that simplifies building distributed, event-driven architectures. We begin by discussing the limitations of tightly coupled applications and then demonstrate how distributed systems and EventBridge can solve these challenges.

Understanding Tightly Coupled vs. Distributed Applications

Tightly coupled applications require extensive coordination between teams. When one service changes, every interdependent component might also need to be updated. This interconnectedness significantly increases operational complexity as the application scales.

In contrast, distributed applications consist of independent components that scale separately. Each team manages only their specific service, thereby reducing cross-dependencies. An event-driven architecture further decouples these components, allowing them to interact solely through events. However, managing an event system brings its own challenges such as ensuring event delivery during server crashes, handling high event volumes, and maintaining overall resilience.

This is where AWS EventBridge becomes an essential service. By providing a scalable and fully managed event bus, EventBridge makes it easier to integrate AWS services, third-party applications, and your custom applications—all without building an on-premises event infrastructure.

Key Benefits of AWS EventBridge

AWS EventBridge supports loosely coupled, event-driven architectures, offering benefits such as:

• Decoupling of Components: Services communicate through events, reducing direct dependencies.
• Scalability: Components scale based purely on event loads.
• Real-Time Processing: Efficient handling of high volumes of events.
• Advanced Routing & Filtering: Define rules to trigger specific actions based on event properties.

For example, you can configure a rule that instructs EventBridge to trigger two Lambda functions and one ECS task when an event with designated properties is received—while ignoring irrelevant events.


Components of AWS EventBridge

AWS EventBridge is composed of three primary components: Event Bus, Pipes, and Scheduler. Below is an overview of each component.

1. Event Bus

An Event Bus serves as a centralized hub where events from various sources—such as AWS services, custom applications, or SaaS applications—are collected and routed to the appropriate targets based on defined rules.


Every AWS account includes a default event bus, allowing you to start sending events immediately. Additionally, you can create custom event buses to organize events by application or functionality. Once events are on the bus, rules determine which services (e.g., Lambda functions, SNS topics, API destinations) are triggered.


2. Pipes

EventBridge Pipes offer a streamlined integration mechanism by directly routing events from a source to a target. Pipes provide additional functionalities such as:

• Filtering: Forward only the events that meet defined criteria.
• Transformation: Convert event data into the required format before reaching the target.
• Enrichment: Enhance event data by adding supplementary information (e.g., using a Lambda function to retrieve additional details based on a transaction ID).

This targeted approach reduces overhead by processing only essential events.


3. Scheduler

The EventBridge Scheduler is a serverless service that allows you to effectively schedule tasks and events. With configurable scheduling patterns, delivery windows, and retry policies, the Scheduler ensures that critical tasks are executed exactly when needed.


Advanced Features of AWS EventBridge

AWS EventBridge offers several advanced features designed to further enhance your event-driven architecture:

API Integrations

EventBridge easily connects to various API endpoints, whether hosted on-premises or provided by third-party SaaS providers. This low-code integration option helps manage throughput and authentication, ensuring secure communication.

Event Replay

Event replay allows you to reprocess historical events by sending them back onto an event bus or a specific rule. This feature is invaluable for debugging, as it lets you analyze past events in real time to pinpoint issues in your architecture.

Schema Registry

To maintain consistency in event structures across teams, EventBridge provides a schema registry. This registry stores event schema definitions so that developers can easily search, understand, and adhere to agreed-upon event formats, ensuring smooth interoperability.


Reliable Event Delivery

EventBridge ensures at-least-once event delivery with automatic retries incorporating exponential backoff for up to 24 hours. Events are replicated across multiple availability zones, guaranteeing high availability (with a 99.99% SLA) and continuous application operation.

Integrations with AWS Services

AWS EventBridge integrates seamlessly with over 200 built-in event sources and targets. This extensive integration includes popular AWS services such as Lambda functions, SQS, SNS, Step Functions, Kinesis Data Streams, and Kinesis Data Firehose.

For a complete list of supported integrations and detailed usage scenarios, refer to the AWS EventBridge documentation.