@aws-solutions-constructs/aws-alb-lambda

aws-alb-lambda module

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All classes are under active development and subject to non-backward compatible changes or removal in any future version. These are not subject to the Semantic Versioning model. This means that while you may use them, you may need to update your source code when upgrading to a newer version of this package.

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Reference Documentation:	https://docs.aws.amazon.com/solutions/latest/constructs/

Language	Package
Python	aws_solutions_constructs.aws_alb_lambda
Typescript	@aws-solutions-constructs/aws-alb-lambda
Java	software.amazon.awsconstructs.services.alblambda

This AWS Solutions Construct implements an an Application Load Balancer to an AWS Lambda function

Here is a minimal deployable pattern definition in Typescript:

  // Obtain a pre-existing certificate from your account
  const certificate = acm.Certificate.fromCertificateArn(
        scope,
        'existing-cert',
        "arn:aws:acm:us-east-1:123456789012:certificate/11112222-3333-1234-1234-123456789012"
      );
  const props: AlbToLambdaProps = {
    lambdaFunctionProps: {
      code: lambda.Code.fromAsset(`${__dirname}/lambda`),
      runtime: lambda.Runtime.NODEJS_14_X,
      handler: 'index.handler'
    },
    listenerProps: {
      certificates: [ certificate ]
    },
    publicApi: true
  };
  new AlbToLambda(stack, 'new-construct', props);

Initializer

new AlbToLambda(scope: Construct, id: string, props: AlbToLambdaProps);

Parameters

• scope Construct
• id string
• props AlbToLambdaProps

Pattern Construct Props

Name	Type	Description
loadBalancerProps?	elasticloadbalancingv2.ApplicationLoadBalancerProps	Optional custom properties for a new loadBalancer. Providing both this and existingLoadBalancer is an error. This cannot specify a VPC, it will use the VPC in existingVpc or the VPC created by the construct.
existingLoadBalancerObj?	elasticloadbalancingv2.ApplicationLoadBalancer	Existing Application Load Balancer to incorporate into the construct architecture. Providing both this and loadBalancerProps is an error. The VPC containing this loadBalancer must match the VPC provided in existingVpc.
listenerProps?	ApplicationListenerProps	Props to define the listener. Must be provided when adding the listener to an ALB (eg - when creating the alb), may not be provided when adding a second target to an already established listener. When provided, must include either a certificate or protocol: HTTP
targetProps?	ApplicationTargetGroupProps	Optional custom properties for a new target group. While this is a standard attribute of props for ALB constructs, there are few pertinent properties for a Lambda target.
ruleProps?	AddRuleProps	Rules for directing traffic to the target being created. May not be specified for the first listener added to an ALB, and must be specified for the second target added to a listener. Add a second target by instantiating this construct a second time and providing the existingAlb from the first instantiation.
vpcProps?	ec2.VpcProps	Optional custom properties for a VPC the construct will create. This VPC will be used by the new ALB and any Private Hosted Zone the construct creates (that's why loadBalancerProps and privateHostedZoneProps can't include a VPC). Providing both this and existingVpc is an error.
existingLambdaObj?	lambda.Function	Existing instance of Lambda Function object, providing both this and lambdaFunctionProps will cause an error.
lambdaFunctionProps?	lambda.FunctionProps	Optional user provided props to override the default props for the Lambda function.
existingVpc?	ec2.IVpc	An existing VPC in which to deploy the construct. Providing both this and vpcProps is an error. If the client provides an existing load balancer and/or existing Private Hosted Zone, those constructs must exist in this VPC.
logAlbAccessLogs?	boolean	Whether to turn on Access Logs for the Application Load Balancer. Uses an S3 bucket with associated storage costs.Enabling Access Logging is a best practice. default - true
albLoggingBucketProps?	s3.BucketProps	Optional properties to customize the bucket used to store the ALB Access Logs. Supplying this and setting logAccessLogs to false is an error. @default - none
publicApi	boolean	Whether the construct is deploying a private or public API. This has implications for the VPC and ALB.

Pattern Properties

Name	Type	Description
vpc	ec2.IVpc	The VPC used by the construct (whether created by the construct or providedb by the client)
loadBalancer	elasticloadbalancingv2.ApplicationLoadBalancer	The Load Balancer used by the construct (whether created by the construct or provided by the client)
lambdaFunction	lambda.Function	Returns an instance of the Lambda function used in the pattern.
listener	elb.ApplicationListener	The listener used by this pattern.

Default settings

Out of the box implementation of the Construct without any override will set the following defaults:

Application Load Balancer

• Creates or configures an Application Load Balancer with:
  • Required listeners
  • New target group with routing rules if appropriate

AWS Lambda Function

• Configure limited privilege access IAM role for Lambda function
• Enable reusing connections with Keep-Alive for NodeJs Lambda function
• Enable X-Ray Tracing
• Set Environment Variables
  • AWS_NODEJS_CONNECTION_REUSE_ENABLED (for Node 10.x and higher functions)

Architecture

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