Lambda ALB Translate

This Terraform configuration creates an AWS Lambda function integrated with an Application Load Balancer (ALB) that provides translation services using AWS Translate.

Architecture

• VPC: Uses existing VPC (you provide VPC ID)
• ALB: Application Load Balancer in existing public subnets for external access
• Lambda: Function in existing private subnets with VPC configuration
• IAM: Proper roles and policies for Lambda to access AWS Translate
• Security Groups: Configured for ALB and Lambda communication

Features

• RESTful API endpoints for translation
• Health check endpoint
• Language listing endpoint
• CORS support
• Error handling and validation
• VPC security

API Endpoints

• GET / - API documentation
• GET /health - Health check
• POST /translate - Translate text
• GET /languages - List supported languages

Prerequisites

• AWS CLI configured with appropriate credentials
• Terraform >= 1.0 installed
• Python 3.9+ (for Lambda function)

Usage

1. Clone and navigate to the directory:

   cd lambda-alb-translate

2. Copy and customize variables:

   cp terraform.tfvars.example terraform.tfvars
   # Edit terraform.tfvars with your VPC and subnet IDs

3. Initialize Terraform:

   terraform init

4. Plan the deployment:

   terraform plan

5. Deploy the infrastructure:

   terraform apply

6. Get the ALB endpoint:

   terraform output api_endpoint

API Usage Examples

Health Check

curl http://your-alb-dns-name/health

List Supported Languages

curl http://your-alb-dns-name/languages

Translate Text

curl -X POST http://your-alb-dns-name/translate \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Hello, world!",
    "source_language_code": "en",
    "target_language_code": "es"
  }'

Example Response

{
  "translated_text": "¡Hola, mundo!",
  "source_language_code": "en",
  "target_language_code": "es",
  "original_text": "Hello, world!"
}

Configuration

Variables

• aws_region: AWS region for resources (default: us-east-1)
• project_name: Name prefix for all resources (default: lambda-alb-translate)
• vpc_id: ID of the existing VPC (required)
• public_subnet_ids: List of existing public subnet IDs (required)
• private_subnet_ids: List of existing private subnet IDs (required)
• lambda_memory_size: Memory allocation for Lambda (default: 256)
• lambda_timeout: Timeout for Lambda function (default: 30)

IAM Permissions

The Lambda function requires the following AWS Translate permissions:

• translate:TranslateText
• translate:ListLanguages
• translate:DescribeTextTranslationJob
• translate:ListTextTranslationJobs

Cleanup

To destroy all resources:

terraform destroy

Security Considerations

• Lambda function runs in your existing private subnets
• ALB is in your existing public subnets with security group restrictions
• IAM roles follow least privilege principle
• Uses your existing VPC for network isolation

Monitoring

• CloudWatch logs are automatically enabled for the Lambda function
• ALB provides access logs and metrics
• Health checks monitor Lambda function availability

Troubleshooting

1. Lambda function not responding: Check VPC configuration and security groups
2. ALB health checks failing: Verify Lambda function is returning 200 status for /health
3. Translation errors: Check IAM permissions for AWS Translate
4. CORS issues: Verify the Lambda function includes proper CORS headers

Cost Optimization

• ALB charges apply for load balancer hours and LCU usage
• Lambda charges for execution time and memory
• AWS Translate charges per character translated
• Consider using NAT Gateway for private subnet internet access (should be configured in your existing VPC)