aws-patterns

# AWS Patterns Serverless and managed service patterns for AWS production workloads. ## Lambda Best Practices ```typescript // Cold start optimization: keep handler thin, initialize outside handler import { DynamoDBClient } from '@aws-sdk/client-dynamodb' import { DynamoDBDocumentClient, GetCommand } from '@aws-sdk/lib-dynamodb' // Initialized ONCE per container (reused across invocations) const client = DynamoDBDocumentClient.from(new DynamoDBClient({})) export const handler = async (event: APIGatewayProxyEvent) => { try { const userId = event.pathParameters?.id if (!userId) { return { statusCode: 400, body: JSON.stringify({ error: 'Missing user ID' }) } } const result = await client.send(new GetCommand({ TableName: process.env.USERS_TABLE!, Key: { pk: `USER#${userId}`, sk: `PROFILE` } })) if (!result.Item) { return { statusCode: 404, body: JSON.stringify({ error: 'User not found' }) } } return { statusCode: 200, headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(result.Item) } } catch (err) { console.error('Handler error:', err) return { statusCode: 500, body: JSON.stringify({ error: 'Internal server error' }) } } } ``` ## S3 Event Processing ```typescript // S3 → Lambda: process uploaded files import { S3Client, GetObjectCommand } from '@aws-sdk/client-s3' const s3 = new S3Client({}) export const handler = async (event: S3Event) => { for (const recor...