An example of AWS CDK that creates an API Gateway with existing Lambda and Domain

katryo — Wed, 11 Dec 2019 19:46:38 +0000

import cdk = require("@aws-cdk/core");
import apigateway = require("@aws-cdk/aws-apigateway");
import lambda = require("@aws-cdk/aws-lambda");

interface MultistackProps extends cdk.StackProps {
  stage: "staging" | "production";
  functionArn: string;
  domainName: string;
  domainNameAliasHostedZoneId: string;
  domainNameAliasTarget: string;
}

export class MuaFrontendApiGatewayStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props: MultistackProps) {
    super(scope, id, props);

    const domain = apigateway.DomainName.fromDomainNameAttributes(
      this,
      `existing-domain-${props.stage}`,
      {
        domainName: props.domainName,
        domainNameAliasHostedZoneId: props.domainNameAliasHostedZoneId,
        domainNameAliasTarget: props.domainNameAliasTarget
      }
    );

    const api = new apigateway.RestApi(this, `api-gateway-${props.stage}`, {
      restApiName: `api-gateway-${props.stage}`
    });

    new apigateway.BasePathMapping(this, `basePathMapping-${props.stage}`, {
      domainName: domain,
      restApi: api
    });

    const lambdaOne = lambda.Function.fromFunctionArn(
      this,
      `lambdaOne-${props.stage}`,
      props.functionArn
    );
    const lambdaIntegration = new apigateway.LambdaIntegration(lambdaOne, {
      contentHandling: apigateway.ContentHandling.CONVERT_TO_BINARY
    });
    const rootProxy = api.root.addProxy({
      anyMethod: false
    });

    const methodOne = rootProxy.addMethod("ANY", lambdaIntegration);

    new lambda.CfnPermission(this, `permission-for-lambda-${props.stage}`, {
      action: "lambda:invokeFunction",
      principal: "apigateway.amazonaws.com",
      functionName: lambdaOne.functionArn,
      sourceArn: methodOne.methodArn.toString()
    });
  }
}

AWS CDK sample with Existing S3 bucket and existing SNS topic

katryo — Thu, 19 Sep 2019 21:34:13 +0000

You cannot add a new S3 notification to existing S3 buckets by CloudFormation. However, you can add an SQS subscription to existing SNS topics.

S3 => SNS topic => SQS subscription => Lambda

import core = require("@aws-cdk/core");
import lambda = require("@aws-cdk/aws-lambda");
import s3 = require("@aws-cdk/aws-s3");
import sns = require("@aws-cdk/aws-sns");
import sqs = require("@aws-cdk/aws-sqs");
import { SqsEventSource } from "@aws-cdk/aws-lambda-event-sources";
import { SqsSubscription } from "@aws-cdk/aws-sns-subscriptions";

export class ExistingS3BucketAndSNSTopicToLambdaThroughSQS extends core.Construct {
  constructor(scope: core.Construct, id: string) {
    super(scope, id);

    const bucket = s3.Bucket.fromBucketName(
      this,
      "ExistingS3Bucket",
      "bucketName"
    );

    const handler = new lambda.Function(this, "lambda", {
      runtime: lambda.Runtime.NODEJS_10_X,
      code: lambda.Code.asset("lambda/dist"),
      handler: "index.main",
      timeout: core.Duration.seconds(30),
      environment: {
        BUCKET_NAME: bucket.bucketName
      }
    });

    bucket.grantRead(handler);

    const topic = sns.Topic.fromTopicArn(
      this,
      "ExistingSNSTopic",
      `arn:${core.Aws.PARTITION}:sns:${core.Aws.REGION}:${core.Aws.ACCOUNT_ID}:existing-sns-topic`
    );
    const queue = new sqs.Queue(this, "queue");

    topic.addSubscription(new SqsSubscription(queue));

    handler.addEventSource(
      new SqsEventSource(queue, {
        batchSize: 1
      })
    );
  }
}

This example is working well with AWS CDK v1.6.1. In the future it might be broken because AWS CDK is in its public beta.

Gist: https://gist.github.com/katryo/ff3cf8b5e3f12823ad7bc2468db054cd

DEV Community: katryo

An example of AWS CDK that creates an API Gateway with existing Lambda and Domain

AWS CDK sample with Existing S3 bucket and existing SNS topic