Lambda Rust HTTP

A minimal AWS Lambda example in Rust that responds with "Hello, world!" via API Gateway, with developer-friendly Devcontainer setup.

🚀 Quick Start

Prerequisites

• Docker Desktop
• VS Code with Dev Containers extension
• AWS CLI configured with appropriate credentials

1. Open in Dev Container

1. Clone this repository
2. Open in VS Code
3. When prompted, click "Reopen in Container"
4. Wait for the container to build and install dependencies

2. Local Development

# Watch for changes and run locally
cargo lambda watch

# In another terminal, test locally
curl http://localhost:9000/
# Response: {"message":"Hello, world!"}

3. Build for Production

# Build ARM64 binary for AWS Lambda
cargo lambda build --release --arm64

# The binary will be created at:
# target/lambda/lambda-rust-http/bootstrap

4. Deploy to AWS

# Navigate to infrastructure directory
cd infra

# Initialize Terraform
terraform init

# Plan deployment
terraform plan

# Deploy infrastructure
terraform apply

# Get the API Gateway URL
terraform output api_gateway_url

5. Test the Deployed Function

# Test with the URL from terraform output
curl https://<api-id>.execute-api.<region>.amazonaws.com/prod/
# Response: {"message":"Hello, world!"}

🏗️ Project Structure

lambda-rust-http/
├── .devcontainer/          # VS Code Dev Container config
│   ├── devcontainer.json   # Container settings
│   └── Dockerfile         # Container image
├── src/
│   └── main.rs            # Lambda function code
├── infra/                  # Terraform infrastructure
│   ├── main.tf            # Main infrastructure config
│   ├── variables.tf       # Variable definitions
│   └── outputs.tf         # Output values
├── Cargo.toml             # Rust dependencies
└── README.md              # This file

🔧 Development Workflow

1. Local Development: Use cargo lambda watch for hot reloading
2. Testing: Test locally before deploying
3. Build: Use cargo lambda build --release --arm64 for production
4. Deploy: Use Terraform to deploy infrastructure
5. Test: Verify the deployed function works

📦 Build Artifacts

The build process creates:

• Binary: target/lambda/lambda-rust-http/bootstrap (ARM64)
• Package: target/lambda/lambda-rust-http.zip (for Terraform)

🌐 API Endpoints

• Root: GET / → Returns {"message":"Hello, world!"}
• Any Path: ANY /{proxy+} → Same response (handles all routes)

🛠️ Technologies Used

• Rust: Programming language
• lambda_http: AWS Lambda HTTP runtime
• cargo-lambda: Build tool for Rust Lambda functions
• Terraform: Infrastructure as Code
• Dev Containers: Consistent development environment

📚 Reference

This implementation is based on the official AWS sample template: 👉 basic-http-function example in aws-lambda-rust-runtime

🔍 Troubleshooting

Common Issues

1. Build fails: Ensure you're using the Dev Container with Rust 1.70+
2. Terraform errors: Check AWS credentials and region configuration
3. Lambda cold start: First invocation may be slower

Useful Commands

# Check Rust version
rustc --version

# Check cargo-lambda installation
cargo lambda --version

# Check AWS CLI
aws --version

# Check Terraform
terraform --version

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.