[AWS] EventBridge

Amazon EventBridge is a serverless event bus service that makes it easy to connect your applications with data from a variety of sources. It helps you to build event-driven architectures that are loosely coupled and distributed.

Serverless Event Router – Amazon EventBridge – Amazon Web Services

• EventBridge delivers a stream of real-time data from your applications or AWS services and routes that data to targets such as AWS Lambda using the routing rules.
• EventBridge is the updated version that replaces CloudWatch Events.

Components

Events

• Changes in your resources and sent to EventBridge
• Event Structure
  • source
  • detail
  • detail-type

{
  "version": "0",
  "id": "ac51d123-45e1-460a-a1fa-e15d188c17e1",
  "detail-type": "EC2 Instance State-change Notification",
  "source": "aws.ec2",
  "account": "123456789101",
  "time": "2022-12-25T13:11:28Z",
  "region": "us-east-1",
  "resources": [
    "arn:aws:ec2:us-east-1:123456789101:instance/i-1234567890abcdef0"
  ],
  "detail": {
    "instance-id": "i-1234567890abcdef0",
    "state": "stopped"
  }
}

Destinations

• Targets
  • Resources or endpoints that EventBridge sends events to after matching a rule.
• You can configure up to 5 destinations per rule.

Rules

• Rules are the glue in the pipeline.
• A Rule matches an event and sends it to its designated (single or multiple) targets.
• Events can be matched to rules by:
  • Rate-based or cron-based schedule
  • Event pattern matching

{
  "source": ["aws.ec2"],
  "detail-type": ["EC2 Instance State-change Notification"],
  "detail": {
    "state": ["stopping", "stopped"]
  }
}

Replay

• Events are saved (archived), and we can replay them later

Event Bus

• “Event Bus” is a serverless pipeline that can deliver events from different sources.
• Every account has a default event bus.
  • The default event bus is used for the events from AWS services.
  • You can create a custom event bus for custom applications.
• “Rules” are associated with buses and are applied when matching events arrive.
  • There is a limit: 300 rules per event bus!

Working with Lambda

• EventBridge can invoke Lambda functions asynchronously.