Deploy an API Gateway

Table of Content

Refactor Lambda functions name

Before introduce the API Gateway, we will update our stack code to distinguish between the Lambda functions and the API Gateway method integrations.

  • Rename the variables from:

    • hello to helloHandler.
    • usersList to usersListHandler.
    • userGet to userGetHandler.
    • userCreate to userCreateHandler.
    • userUpdate to userUpdateHandler.
    • userDelete to userDeleteHandler.

  • Your code should now look like this:

    alt text

  • If you run cdk diff, there is no differences.

    alt text

Although you rename variables in your CDK stack. There is nothing changes in perspective of the deployed stack.

Deploy a Rest API Gateway and integrate with UsersListHandler

Add CDK for the Rest API Gateway and the integration

  • In the CDK stack file (cdk-workshop-stack.ts), inside the constructor and below code for granting permissions to Lambda functions, add the following code:

    // Rest API Gateway with Lambda integration
const gateway = new LambdaRestApi(this, "UsersAPI", {
  handler: helloHandler,
  proxy: false,
});

// Resource /users
const usersResource = gateway.root.addResource("users");

// Resource /users - GET method
const usersListIntegration = new LambdaIntegration(usersListHandler, {
  proxy: false,
  integrationResponses: [{ statusCode: "200" }],
});
const usersGet = usersResource.addMethod("GET", usersListIntegration, {
  methodResponses: [{ statusCode: "200" }],
});

  • Add the import to the top of the stack file:

    import { LambdaIntegration, LambdaRestApi } from "aws-cdk-lib/aws-apigateway";

  • Your CDK stack file should now look like this:

    alt text

Run cdk deploy to deploy your CDK stack

  • Run cdk deploy to deploy deploy your local stack

    cdk deploy

    • Output

      ✨  Synthesis time: 9.99s

Stack CdkWorkshopStack
IAM Statement Changes
┌───┬─────────────────────────┬────────┬───────────────────────┬──────────────────────────────────┬────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│   │ Resource                │ Effect │ Action                │ Principal                        │ Condition                                                                                                                                              │
├───┼─────────────────────────┼────────┼───────────────────────┼──────────────────────────────────┼────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤
│ + │ ${UsersListHandler.Arn} │ Allow  │ lambda:InvokeFunction │ Service:apigateway.amazonaws.com │ "ArnLike": {                                                                                                                                           │
│   │                         │        │                       │                                  │   "AWS:SourceArn": "arn:${AWS::Partition}:execute-api:${AWS::Region}:${AWS::AccountId}:${UsersAPIDF91FF81}/${UsersAPI/DeploymentStage.prod}/GET/users" │
│   │                         │        │                       │                                  │ }                                                                                                                                                      │
│ + │ ${UsersListHandler.Arn} │ Allow  │ lambda:InvokeFunction │ Service:apigateway.amazonaws.com │ "ArnLike": {                                                                                                                                           │
│   │                         │        │                       │                                  │   "AWS:SourceArn": "arn:${AWS::Partition}:execute-api:${AWS::Region}:${AWS::AccountId}:${UsersAPIDF91FF81}/test-invoke-stage/GET/users"                │
│   │                         │        │                       │                                  │ }                                                                                                                                                      │
└───┴─────────────────────────┴────────┴───────────────────────┴──────────────────────────────────┴────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
(NOTE: There may be security-related changes not in this list. See https://github.com/aws/aws-cdk/issues/1299)


Do you wish to deploy these changes (y/n)?

    • Type y and press Enter to confirm.

      alt text

  • Copy the UsersAPIEndpoint from deploy outputs.

Test the API Gateway and the integration

  • To test the API Gateway, invoke a GET HTTP request to the /users path (of the UsersAPIEndpoint).

    curl https://b22ew70ek7.execute-api.ap-southeast-1.amazonaws.com/prod/users

    Replace the endpoint with yours and notice the /prod suffix of the endpoint.

    alt text