AWS SDK Integration

Node.js (SDK v3)

Client Setup

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

const client = new DynamoDBClient({ region: process.env.AWS_REGION }); const ddb = DynamoDBDocumentClient.from(client);

DynamoDB

// Put item await ddb.send(new PutCommand({ TableName: 'Users', Item: { pk: USER#${id}, sk: 'PROFILE', name, email, createdAt: Date.now() }, ConditionExpression: 'attribute_not_exists(pk)', // Prevent overwrite }));

// Get item const { Item } = await ddb.send(new GetCommand({ TableName: 'Users', Key: { pk: USER#${id}, sk: 'PROFILE' }, }));

// Query const { Items } = await ddb.send(new QueryCommand({ TableName: 'Orders', KeyConditionExpression: 'pk = :pk AND begins_with(sk, :prefix)', ExpressionAttributeValues: { ':pk': USER#${userId}, ':prefix': 'ORDER#' }, }));

Lambda Invocation

import { LambdaClient, InvokeCommand } from '@aws-sdk/client-lambda';

const lambda = new LambdaClient({}); const { Payload } = await lambda.send(new InvokeCommand({ FunctionName: 'processOrder', InvocationType: 'Event', // async ('RequestResponse' for sync) Payload: JSON.stringify({ orderId }), }));

SNS

import { SNSClient, PublishCommand } from '@aws-sdk/client-sns';

const sns = new SNSClient({}); await sns.send(new PublishCommand({ TopicArn: process.env.ORDER_TOPIC_ARN, Message: JSON.stringify({ orderId, status: 'completed' }), MessageAttributes: { eventType: { DataType: 'String', StringValue: 'ORDER_COMPLETED' }, }, }));

CloudWatch Metrics

import { CloudWatchClient, PutMetricDataCommand } from '@aws-sdk/client-cloudwatch';

const cw = new CloudWatchClient({}); await cw.send(new PutMetricDataCommand({ Namespace: 'MyApp', MetricData: [{ MetricName: 'OrderProcessingTime', Value: durationMs, Unit: 'Milliseconds', Dimensions: [{ Name: 'Service', Value: 'OrderProcessor' }], }], }));

Python (boto3)

import boto3

DynamoDB

dynamodb = boto3.resource('dynamodb') table = dynamodb.Table('Users') table.put_item(Item={'pk': f'USER#{id}', 'sk': 'PROFILE', 'name': name}) response = table.get_item(Key={'pk': f'USER#{id}', 'sk': 'PROFILE'})

Lambda

lambda_client = boto3.client('lambda') lambda_client.invoke(FunctionName='processOrder', InvocationType='Event', Payload=json.dumps({'orderId': order_id}))

SNS

sns = boto3.client('sns') sns.publish(TopicArn=topic_arn, Message=json.dumps(payload))

Credentials (never hardcode)

Environment Method

Local dev ~/.aws/credentials or AWS_PROFILE

EC2/ECS Instance/task IAM role (automatic)

Lambda Execution role (automatic)

CI/CD AWS_ACCESS_KEY_ID

• AWS_SECRET_ACCESS_KEY env vars

Anti-Patterns

Anti-Pattern Fix

Hardcoded credentials Use IAM roles, env vars, or credential chain

Single-region architecture Use multi-AZ, consider multi-region for DR

No retries on SDK calls SDK v3 retries automatically — configure maxAttempts

Scan instead of Query (DynamoDB) Design keys for Query access patterns

Synchronous Lambda calls in request path Use async invocation or SQS

Production Checklist

• IAM roles with least privilege

• No hardcoded credentials

• SDK retry configuration (maxAttempts )

• CloudWatch alarms on error metrics

• VPC endpoints for S3/DynamoDB (saves NAT costs)

• Resource tagging for cost allocation