Skip to content

event-bridge.md

Latest commit

 

History

History
252 lines (214 loc) · 7.07 KB

event-bridge.md

File metadata and controls

252 lines (214 loc) · 7.07 KB

EventBridge Event

The EventBridge makes it possible to connect applications using data from external sources (e.g. own applications, SaaS) or AWS services. The eventBridge event types helps setting up AWS Lambda functions to react to events coming in via the EventBridge.

Note: Prior to CLI version 2.27.0, eventBridge resources were provisioned with Custom Resources. Native CloudFormation support is the default in v3. The provider.eventBridge.useCloudFormation compatibility setting is no longer needed and is scheduled for removal in osls v4.0.0. Native CloudFormation also adds the ability to define eventBus with CF intrinsic functions as values.

Setting up a scheduled event

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          schedule: rate(10 minutes)
          input:
            key1: value1

Enabling / Disabling

Note: eventBridge events are enabled by default. Use enabled: false to disable the rule.

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          enabled: false
          schedule: rate(10 minutes)
          input:
            key1: value1

Setting a custom name and description

Note: eventBridge events by default are named with the lambda function's name with a suffix for the rule position. Set the name property within eventBridge to change this functionality.

A description can also be specified. These are not required properties.

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          name: event-bridge-custom-name
          description: a description of my eventBridge event's purpose
          schedule: rate(10 minutes)
          input:
            key1: value1

Setting up event pattern matching

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          pattern:
            source:
              - aws.cloudformation
            detail-type:
              - AWS API Call via CloudTrail
            detail:
              eventSource:
                - cloudformation.amazonaws.com

Here is an example that uses "prefix matching" to filter EventBridge events produced by S3 (the bucket must have the EventBridge notification enabled):

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          pattern:
            source:
              - aws.s3
            detail-type:
              - Object Created
            detail:
              bucket:
                name:
                  - photos
              object:
                key:
                  - prefix: 'uploads/'

Using a different Event Bus

The eventBridge event source will use the default event bus (the one AWS uses internally) when none is explicitly specified.

osls will create the eventBus for you if you provide a name for it. Otherwise, if literal arn or reference to an existing event bus name via CF intrinsic function is provided, osls will attach to it.

Creating an event bus

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          eventBus: custom-saas-events
          pattern:
            source:
              - saas.external

Reusing an existing event bus

If you want to reuse an existing event bus, you can define it with literal arn or with a reference to an existing event bus name via CF intrinsic functions. Referencing via intrinsic functions is available with the native CloudFormation support used by default in v3.

Using literal arn:

- eventBridge:
    eventBus: arn:aws:events:us-east-1:12345:event-bus/custom-private-events
    pattern:
      source:
        - custom.private
    inputTransformer:
      inputPathsMap:
        eventTime: '$.time'
      inputTemplate: '{"time": <eventTime>, "key1": "value1"}'

Using reference to event bus' name via GetAtt CF intrinsic function:

- eventBridge:
    eventBus: !GetAtt EventBusResource.Name
    pattern:
      source:
        - custom.private
    inputTransformer:
      inputPathsMap:
        eventTime: '$.time'
      inputTemplate: '{"time": <eventTime>, "key1": "value1"}'

Note: It is not possible to reference event bus ARN with CF intrinsic function as it makes it impossible for osls to construct valid SourceArn for AWS::Lambda::Permission resource.

Using reference to event bus' name via Ref CF intrinsic functions:

- eventBridge:
    eventBus: !Ref EventBusResource
    pattern:
      source:
        - custom.private
    inputTransformer:
      inputPathsMap:
        eventTime: '$.time'
      inputTemplate: '{"time": <eventTime>, "key1": "value1"}'

Using different input types

You can specify different input types which will produce different input values ​​for the Lambda function.

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          pattern:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
          input:
            key1: value1
            key2: value2
            stageParams:
              stage: dev
      - eventBridge:
          pattern:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
          inputPath: '$.stageVariables'
      - eventBridge:
          pattern:
            source:
              - 'aws.ec2'
            detail-type:
              - 'EC2 Instance State-change Notification'
            detail:
              state:
                - pending
          inputTransformer:
            inputPathsMap:
              eventTime: '$.time'
            inputTemplate: '{"time": <eventTime>, "key1": "value1"}'

Adding a DLQ to an event rule

DeadLetterQueueArn is not available for custom resources, only for native CloudFormation.

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          eventBus: custom-saas-events
          pattern:
            source:
              - saas.external
          deadLetterQueueArn:
            Fn::GetAtt:
              - QueueName
              - Arn

Adding a retry policy to an event rule

RetryPolicy is not available for custom resources, only for native CloudFormation.

functions:
  myFunction:
    handler: index.handler
    events:
      - eventBridge:
          eventBus: custom-saas-events
          pattern:
            source:
              - saas.external
          deadLetterQueueArn:
            Fn::GetAtt:
              - QueueName
              - Arn
          retryPolicy:
            maximumEventAge: 3600
            maximumRetryAttempts: 3