Interface Summary
Interface Description

LambdaDestinationOptions
Options for a Lambda destination.

Interface Summary
Interface	Description
LambdaDestinationOptions	Options for a Lambda destination.

Class Summary
Class	Description
EventBridgeDestination	Use an Event Bridge event bus as a Lambda destination.
LambdaDestination	Use a Lambda function as a Lambda destination.
LambdaDestination.Builder	A fluent builder for `LambdaDestination`.
LambdaDestinationOptions.Builder	A builder for `LambdaDestinationOptions`
LambdaDestinationOptions.Jsii$Proxy	An implementation for `LambdaDestinationOptions`
SnsDestination	Use a SNS topic as a Lambda destination.
SqsDestination	Use a SQS queue as a Lambda destination.

Package software.amazon.awscdk.services.lambda.destinations Description

Amazon Lambda Destinations Library

---

This library provides constructs for adding destinations to a Lambda function. Destinations can be added by specifying the onFailure or onSuccess props when creating a function or alias.

Destinations

The following destinations are supported

Lambda function
SQS queue
SNS topic
EventBridge event bus

Example with a SNS topic for successful invocations:

 // Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
 import software.amazon.awscdk.services.lambda.*;
 import software.amazon.awscdk.services.lambda.destinations.*;
 import software.amazon.awscdk.services.sns.*;
 
 Topic myTopic = new Topic(this, "Topic");
 
 Function myFn = new Function(this, "Fn", new FunctionProps()
         // other props
         .onSuccess(new SnsDestination(myTopic)));

Invocation record

When a lambda function is configured with a destination, an invocation record is created by the Lambda service when the lambda function completes. The invocation record contains the details of the function, its context, and the request and response payloads.

The following example shows the format of the invocation record for a successful invocation:

 {
        "version": "1.0",
        "timestamp": "2019-11-24T23:08:25.651Z",
        "requestContext": {
                "requestId": "c2a6f2ae-7dbb-4d22-8782-d0485c9877e2",
                "functionArn": "arn:aws:lambda:sa-east-1:123456789123:function:event-destinations:$LATEST",
                "condition": "Success",
                "approximateInvokeCount": 1
        },
        "requestPayload": {
                "Success": true
        },
        "responseContext": {
                "statusCode": 200,
                "executedVersion": "$LATEST"
        },
        "responsePayload": "<data returned by the function here>"
 }

In case of failure, the record contains the reason and error object:

 {
     "version": "1.0",
     "timestamp": "2019-11-24T21:52:47.333Z",
     "requestContext": {
         "requestId": "8ea123e4-1db7-4aca-ad10-d9ca1234c1fd",
         "functionArn": "arn:aws:lambda:sa-east-1:123456678912:function:event-destinations:$LATEST",
         "condition": "RetriesExhausted",
         "approximateInvokeCount": 3
     },
     "requestPayload": {
         "Success": false
     },
     "responseContext": {
         "statusCode": 200,
         "executedVersion": "$LATEST",
         "functionError": "Handled"
     },
     "responsePayload": {
         "errorMessage": "Failure from event, Success = false, I am failing!",
         "errorType": "Error",
         "stackTrace": [ "exports.handler (/var/task/index.js:18:18)" ]
     }
 }

Destination-specific JSON format

For SNS/SQS (SnsDestionation/SqsDestination), the invocation record JSON is passed as the Message to the destination.
For Lambda (LambdaDestination), the invocation record JSON is passed as the payload to the function.
For EventBridge (EventBridgeDestination), the invocation record JSON is passed as the detail in the PutEvents call. The value for the event field source is lambda, and the value for the event field detail-type is either 'Lambda Function Invocation Result - Success' or 'Lambda Function Invocation Result – Failure', depending on whether the lambda function invocation succeeded or failed. The event field resource contains the function and destination ARNs. See AWS Events for the different event fields.

Auto-extract response payload with lambda destination

The responseOnly option of LambdaDestination allows to auto-extract the response payload from the invocation record:

 // Example automatically generated without compilation. See https://github.com/aws/jsii/issues/826
 import software.amazon.awscdk.services.lambda.*;
 import software.amazon.awscdk.services.lambda.destinations.*;
 
 Function destinationFn = new Function(this, "Destination", new FunctionProps());
 
 Function sourceFn = new Function(this, "Source", new FunctionProps()
         // other props
         .onSuccess(new LambdaDestination(destinationFn, new LambdaDestinationOptions()
                 .responseOnly(true))));

In the above example, destinationFn will be invoked with the payload returned by sourceFn (responsePayload in the invocation record, not the full record).

When used with onFailure, the destination function is invoked with the error object returned by the source function.

Using the responseOnly option allows to easily chain asynchronous Lambda functions without having to deal with data extraction in the runtime code.