aws-cdk Associate Lambda Function with CloudFront Web Distribution - amazon-web-services

Question

I'm trying to create a CloudFront Web Distribution using aws-cdk. I'm able to successfully create the web distribution but I haven't been able to figure out how to associate a lambda function yet.
Below is a snippet of my Typescript aws-cdk code to create the CloudFront Web Distribution. I removed some of the code that's not relevant.
new cloudfront.CloudFrontWebDistribution(this, 'RetsFilesCDN', {
originConfigs: [
{
s3OriginSource: {
originAccessIdentity: cfAccess, /* A CfnCloudFrontOriginAccessIdentity object created in earlier code */
s3BucketSource: files /* S3 bucket created in earlier code */
},
behaviors: [
{
compress: true,
defaultTtlSeconds: 172800,
isDefaultBehavior: true,
maxTtlSeconds: 31536000,
minTtlSeconds: 0
}
]
}
]
});
The CloudFormation code that I'm trying to get it to generate is something like this:
RetsFilesCDNCFDistribution6F414E1A:
Type: AWS::CloudFront::Distribution
Properties:
DistributionConfig:
CacheBehaviors:
[]
Comment: CDN for files from the Real Estate RETS services that BranchCMS
integrates with
DefaultCacheBehavior:
AllowedMethods:
- GET
- HEAD
CachedMethods:
- GET
- HEAD
Compress: true
DefaultTTL: 172800
ForwardedValues:
Cookies:
Forward: none
QueryString: false
MaxTTL: 259200
MinTTL: 172800
LambdaFunctionAssociations:
- EventType: origin-response
LambdaFunctionARN: lambdaFunctionArnHere
TargetOriginId: origin1
ViewerProtocolPolicy: redirect-to-https
DefaultRootObject: index.html
Enabled: true
HttpVersion: http2
IPV6Enabled: true
Origins:
- DomainName:
Fn::GetAtt:
- RetsFilesC9F78E92
- DomainName
Id: origin1
S3OriginConfig:
OriginAccessIdentity:
Fn::Join:
- ""
- - origin-access-identity/cloudfront/
- Ref: RetsFilesAccess
PriceClass: PriceClass_100
ViewerCertificate:
AcmCertificateArn: arn:aws:acm:us-east-1:666445282096:certificate/25d4967c-c29a-4d11-983f-86d709769372
SslSupportMethod: sni-only
The exact part that I can't seem to generate is:
LambdaFunctionAssociations:
- EventType: origin-response
LambdaFunctionARN: lambdaFunctionArnHere
Thank you in advance for your help.

Answer 1

I'm not sure if this is the best technique, but the following worked for me.
import cdk = require('#aws-cdk/cdk');
import cloudfront = require('#aws-cdk/aws-cloudfront');
import lambda = require('#aws-cdk/aws-lambda');
export class MyStack extends cdk.Stack {
constructor(parent: cdk.App, name: string, props?: cdk.StackProps) {
super(parent, name, props);
// Create the Lambda function
const lambdaFunc = new lambda.Function(this, 'MyLambda', {
YOUR_LAMBDA_PROPERTIES: HERE
});
// Create the CloudFront Web Distribution
const cf = new cloudfront.CloudFrontWebDistribution(this, 'MyCDN', {
YOUR_CLOUDFRONT_PROPERTIES: HERE
});
/**
* THIS IS THE BEGINNING OF THE SOLUTION
*/
// Get the CloudFront Distribution object to add the LambdaFunctionAssociations to
const cfDist = cf.findChild('CFDistribution') as cloudfront.CfnDistribution;
// Manually add the LambdaFunctionAssociations by adding an override
cfDist.addOverride('Properties.DistributionConfig.DefaultCacheBehavior.LambdaFunctionAssociations', [{
EventType: 'origin-response',
LambdaFunctionARN: lambdaFunc.functionArn + ':2'
}]);
/**
* END OF SOLUTION
*/
}
}

Answer 2

Is it possible to associate a newly created function (lamda#edge / cloudfront function) with an existing cloudfront distribution?
The above code only seems to work for a newly created distribution.

Answer 3

you can use this property for the assosiation of lambda function to your cloudfront cache behaviour
import { CfnDistribution.CacheBehaviorProperty } from '#aws-cdk/aws-cloudfront';
CfnDistribution.CacheBehaviorProperty.LambdaFunctionAssociations
for more information click on this link