event-bridge.md

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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 2.27.0 version of the Framework, eventBridge resources were provisioned with Custom Resources. With 2.27.0 an optional support for native CloudFormation was introduced and can be turned on by setting provider.eventBridge.useCloudFormation property to true. It is recommended to migrate to native CloudFormation as it will become a default with next major version. It 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 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

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.

The Serverless Framework will create the eventBus for your 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, Framework will attach to it.

Creating an event bus

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

Re-using 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 only if you use native CloudFormation support with provider.eventBridge.useCloudFormation: true setting:

provider:
  eventBridge:
    useCloudFormation: true

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 Serverless Framework 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