rdb-cdk

AWS CDK construct library for deploying RDB (Realtime Database) infrastructure.

Overview

RDB is a serverless realtime database built on AWS infrastructure. This CDK construct allows you to easily deploy the complete RDB infrastructure to your AWS account.

Features

• 🚀 Serverless Architecture - Built on AWS Lambda, DynamoDB, and AppSync
• ⚡ Real-time Subscriptions - WebSocket connections for instant data updates
• 🔐 Secure by Default - API key authentication and IAM-based access control
• 📊 Scalable - Automatically scales with your application needs
• 🛠️ Easy to Deploy - Single CDK construct for complete infrastructure
• 💰 Cost Effective - Pay only for what you use

Architecture

The RDB construct deploys:

• DynamoDB Tables: Metadata storage for tables and API keys
• AppSync GraphQL API: Real-time subscriptions and mutations
• API Gateway REST API: CRUD operations for tables and records
• Lambda Functions: Table management, record operations, schema synchronization
• S3 Bucket: Schema configuration storage
• SQS Queue: Asynchronous table decommissioning
• Secrets Manager: Secure API key encryption
• EventBridge Rules: Automated schema synchronization

Installation

npm install rdb-cdk

Peer Dependencies

This package requires the following peer dependencies:

npm install aws-cdk-lib constructs

Usage

Basic Example

import * as cdk from 'aws-cdk-lib';
import { RdbConstruct } from '@realdb/cdk';

export class MyStack extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // Deploy RDB infrastructure
    const rdb = new RdbConstruct(this, 'MyRdb');

    // Access the API Gateway endpoint
    new cdk.CfnOutput(this, 'RdbApiUrl', {
      value: rdb.api.url,
    });
  }
}

Advanced Configuration

import * as cdk from 'aws-cdk-lib';
import * as dynamodb from 'aws-cdk-lib/aws-dynamodb';
import * as logs from 'aws-cdk-lib/aws-logs';
import { RdbConstruct } from 'rdb-cdk';

const rdb = new RdbConstruct(this, 'MyRdb', {
  // Set removal policy (use RETAIN for production)
  removalPolicy: cdk.RemovalPolicy.DESTROY,
  
  // Configure DynamoDB billing mode
  billingMode: dynamodb.BillingMode.PAY_PER_REQUEST,
  
  // Enable X-Ray tracing
  enableXRayTracing: true,
  
  // Set CloudWatch log retention
  logRetention: logs.RetentionDays.ONE_MONTH,
  
  // Enable API Gateway logging
  enableApiLogging: true,
  
  // Configure CORS origins
  corsOrigins: ['https://myapp.example.com'],
});

Configuration Options

RdbConstructProps

Public Properties

After creating the construct, you can access the following properties:

const rdb = new RdbConstruct(this, 'MyRdb');

// API Gateway REST API
const api = rdb.api;

// AppSync GraphQL API
const appSyncApi = rdb.appSyncApi;

// S3 Configuration Bucket
const configBucket = rdb.configBucket;

// DynamoDB Tables
const tablesTable = rdb.tablesTable;
const apiKeysTable = rdb.apiKeysTable;

Using RDB with the SDK

After deploying the infrastructure, use the RDB SDK to interact with your database:

npm install @realdb/client

import { RdbClient } from '@realdb/client';

const client = new RdbClient({
  endpoint: 'https://your-api-id.execute-api.region.amazonaws.com/prod',
  apiKey: 'your-api-key',
});

// Create a table
const usersTable = await client.createTable({
  name: 'users',
  schema: {
    id: { type: 'string', required: true },
    name: { type: 'string', required: true },
    email: { type: 'string', required: true },
  },
});

// Subscribe to real-time updates
await usersTable.subscribe({
  event: 'create',
  onData: (user) => {
    console.log('New user created:', user);
  },
});

Outputs

The construct creates CloudFormation outputs for important endpoints:

• ApiEndpoint: API Gateway REST API endpoint
• AppSyncEndpoint: AppSync GraphQL endpoint
• AppSyncApiKey: AppSync API key for client connections
• ConfigBucketName: S3 bucket name for schema storage

Cost Considerations

RDB uses serverless AWS services, so costs scale with usage:

• Lambda: Pay per request and execution time
• DynamoDB: Pay per read/write request (on-demand) or provisioned capacity
• AppSync: Pay per request and data transfer
• API Gateway: Pay per API call
• S3: Pay per storage and requests
• SQS: Pay per request (usually minimal)

For development environments, expected costs are typically under $5/month with light usage.

Security Best Practices

1. Production Environments: Use removalPolicy: cdk.RemovalPolicy.RETAIN to prevent accidental data loss
2. CORS Configuration: Specify exact origins instead of '*' in production
3. API Keys: Rotate API keys regularly using the API key management endpoints
4. IAM Policies: Review and restrict Lambda execution role permissions as needed
5. VPC Integration: Consider deploying Lambda functions in a VPC for additional security

Examples

Development Stack

const devRdb = new RdbConstruct(this, 'DevRdb', {
  removalPolicy: cdk.RemovalPolicy.DESTROY, // Easy cleanup
  logRetention: logs.RetentionDays.ONE_WEEK,
  corsOrigins: ['*'], // Allow all origins for testing
});

Production Stack

const prodRdb = new RdbConstruct(this, 'ProdRdb', {
  removalPolicy: cdk.RemovalPolicy.RETAIN, // Prevent data loss
  billingMode: dynamodb.BillingMode.PROVISIONED, // Cost optimization
  logRetention: logs.RetentionDays.ONE_MONTH,
  corsOrigins: ['https://app.example.com'],
  enableXRayTracing: true, // Production monitoring
});

Troubleshooting

Schema Synchronization Issues

If AppSync schema updates fail, check:

1. S3 bucket permissions for Lambda functions
2. CloudWatch logs for SchemaSyncFunction
3. AppSync service role permissions

API Gateway Authorization Errors

If you receive 401/403 errors:

1. Verify API key is correctly generated
2. Check that x-api-key header is included in requests
3. Review Lambda authorizer logs

DynamoDB Throughput Exceeded

If using provisioned billing mode:

1. Increase read/write capacity units
2. Or switch to PAY_PER_REQUEST mode

Support and Contributing

For issues, feature requests, or contributions, please visit the main RDB repository.

License

MIT License - See LICENSE file for details

Related Resources

• RDB SDK Documentation
• AWS CDK Documentation
• AppSync Documentation
• DynamoDB Documentation