Deploying to AWS

Quick Start

// Lambda handler
import { APIGatewayProxyEvent, APIGatewayProxyResult } from 'aws-lambda';

export const handler = async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> => {
  const { id } = event.pathParameters || {};
  return {
    statusCode: 200,
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ id, message: 'Success' }),
  };
};

# Deploy with CDK
npx cdk deploy --all

Features

Common Patterns

S3 Presigned Upload URL

import { S3Client, PutObjectCommand } from '@aws-sdk/client-s3';
import { getSignedUrl } from '@aws-sdk/s3-request-presigner';

const s3 = new S3Client({});

async function getUploadUrl(key: string, contentType: string): Promise<string> {
  const command = new PutObjectCommand({ Bucket: process.env.BUCKET!, Key: key, ContentType: contentType });
  return getSignedUrl(s3, command, { expiresIn: 3600 });
}

DynamoDB Single-Table Pattern

import { DynamoDBDocumentClient, QueryCommand } from '@aws-sdk/lib-dynamodb';

// pk: USER#123, sk: PROFILE | ORDER#timestamp
async function getUserWithOrders(userId: string) {
  const result = await docClient.send(new QueryCommand({
    TableName: process.env.TABLE!,
    KeyConditionExpression: 'pk = :pk',
    ExpressionAttributeValues: { ':pk': `USER#${userId}` },
  }));
  return result.Items;
}

CDK Stack Definition

import * as cdk from 'aws-cdk-lib';
import * as lambda from 'aws-cdk-lib/aws-lambda';
import * as dynamodb from 'aws-cdk-lib/aws-dynamodb';

const table = new dynamodb.Table(this, 'Table', {
  partitionKey: { name: 'pk', type: dynamodb.AttributeType.STRING },
  sortKey: { name: 'sk', type: dynamodb.AttributeType.STRING },
  billingMode: dynamodb.BillingMode.PAY_PER_REQUEST,
});

const fn = new lambda.Function(this, 'Handler', {
  runtime: lambda.Runtime.NODEJS_20_X,
  handler: 'index.handler',
  code: lambda.Code.fromAsset('dist'),
  environment: { TABLE_NAME: table.tableName },
});

table.grantReadWriteData(fn);

Best Practices