Serverless Hero

Lee Gilmore leegilmorecode

Serverless Hero

leegilmorecode / create-table.ts

Created July 31, 2022 05:44

Basic example of a CDK custom resource to create a Postgres table

	import * as AWS from "aws-sdk";

	import {
	CdkCustomResourceEvent,
	CdkCustomResourceHandler,
	CdkCustomResourceResponse,
	} from "aws-lambda";

	import { Client } from "pg";
	import { v4 as uuid } from "uuid";

leegilmorecode / order-service.ts

Created July 31, 2022 05:42

Custom Resource Example with the AWS CDK

	// this custom resource will create our postgres table on deploy if it doesn't exist
	const provider: cr.Provider = new cr.Provider(
	this,
	"CreateOnlineOrdersTableCustomResource",
	{
	onEventHandler: createTableHandler, // this lambda will be called on cfn deploy
	logRetention: logs.RetentionDays.ONE_DAY,
	providerFunctionName: "create-online-table-custom-resource",
	}
	);

leegilmorecode / infra-stack.ts

Created July 31, 2022 05:35

Example of setting up RDS Proxy with AWS CDK

	const dbConnectionGroup: ec2.SecurityGroup = new ec2.SecurityGroup(
	this,
	"RdsProxyDBConnection",
	{
	vpc,
	securityGroupName: "rds-proxy-sg",
	}
	);

	dbConnectionGroup.addIngressRule(

leegilmorecode / infra-stack.ts

Created July 31, 2022 05:31

Workaround of using Serverless Aurora V2 with the AWS CDK

	// https://github.com/aws/aws-cdk/issues/20197
	enum ServerlessInstanceType {
	SERVERLESS = "serverless",
	}

	type CustomInstanceType = ServerlessInstanceType \| ec2.InstanceType;

	const CustomInstanceType = {
	...ServerlessInstanceType,
	...ec2.InstanceType,

leegilmorecode / auth-handler.ts

Created July 21, 2022 15:35

An example Lambda Authorizer that is performing both authZ and authN

	import {
	APIGatewayRequestAuthorizerEvent,
	AuthResponse,
	PolicyDocument,
	} from "aws-lambda";

	import { CognitoJwtVerifier } from "aws-jwt-verify";
	import { CognitoJwtVerifierSingleUserPool } from "aws-jwt-verify/cognito-verifier";
	import axios from "axios";
	import jwt from "jsonwebtoken";

leegilmorecode / get-order.ts

Created July 21, 2022 15:16

An example Lambda which is utilising Middy middeware through an attached Lambda Layer

	import {
	APIGatewayProxyEvent,
	APIGatewayProxyEventPathParameters,
	APIGatewayProxyHandler,
	APIGatewayProxyResult,
	} from "aws-lambda";
	import {
	hydrateContext,
	validateCompanyAccessMiddleware,
	validateTokenUserAccessMiddleware,

leegilmorecode / hydrate-context.ts

Created July 21, 2022 15:10

Lambda middleware using Middy which hydrates the user missions based on an external service

 import { APIGatewayProxyEvent, APIGatewayProxyResult } from "aws-lambda";
 import { UserContext } from "../../../types";
 import axios from "axios";
 import middy from "@middy/core";
 // middleware to ensure that the user is part of the given company i.e. permissions
 export const hydrateContext = (): middy.MiddlewareObj<
   APIGatewayProxyEvent,
   APIGatewayProxyResult

leegilmorecode / validate-company-access.ts

Created July 21, 2022 14:57

Middy middleware which is utilised by our Lambda functions

	import { APIGatewayProxyEvent, APIGatewayProxyResult } from "aws-lambda";

	import { UserContext } from "../../../types";
	import middy from "@middy/core";

	// middleware to ensure that the user is part of the given company i.e. permissions
	// when getting their order for a specific company, as well as checking their role
	export const validateCompanyAccessMiddleware = (
	role: string
	): middy.MiddlewareObj<APIGatewayProxyEvent, APIGatewayProxyResult> => {

leegilmorecode / Internal.ts

Created July 21, 2022 14:49

Example of a Lambda Layer in the CDK

	// create our lambda layer for our middleware
	const validationLayer: lambda.LayerVersion = new lambda.LayerVersion(
	this,
	"ValidationLayer",
	{
	compatibleRuntimes: [
	lambda.Runtime.NODEJS_12_X,
	lambda.Runtime.NODEJS_14_X,
	],
	code: lambda.Code.fromAsset("../layers/validation"),

leegilmorecode / external.ts

Created July 21, 2022 14:45

Example of a Cognito Authorizer being added to an endpoint on API Gateway

	// add the cognito authorizer to our api which validates our tokens using cognito
	const cognitoAuthorizer: apigw.CfnAuthorizer = new apigw.CfnAuthorizer(
	this,
	"APIGatewayAuthorizer",
	{
	name: "sushi-orders-authorizer",
	identitySource: "method.request.header.Authorization",
	providerArns: [userPool.userPoolArn],
	restApiId: ordersAPI.restApiId,
	type: apigw.AuthorizationType.COGNITO,