🪙 AWS SAM Coin Lister

🌟 A serverless cryptocurrency API built with AWS SAM and Lambda.

📊 Get real-time cryptocurrency data with DynamoDB caching for optimal performance.

graph TD
    Client[Client] -->|HTTP Request| APIGateway[API Gateway]
    APIGateway -->|Trigger| Lambda[Lambda Function]
    Lambda -->|Cache Check| DynamoDB[(DynamoDB Cache)]
    Lambda -->|Fetch Data| CoinGecko[CoinGecko API]
    Lambda -->|Update Cache| DynamoDB
    Lambda -->|Response| APIGateway
    APIGateway -->|JSON Response| Client

    style Client fill:#f9f,stroke:#333,stroke-width:2px
    style APIGateway fill:#ff9900,stroke:#333,stroke-width:2px
    style Lambda fill:#ff9900,stroke:#333,stroke-width:2px
    style DynamoDB fill:#ff9900,stroke:#333,stroke-width:2px
    style CoinGecko fill:#ff9900,stroke:#333,stroke-width:2px

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🚀 Quick Start

# Clone & Install
git clone https://github.com/ozers/aws-sam-coin-lister.git
cd aws-sam-coin-lister/list-coins && npm install && cd ..

# Build & Deploy
sam build && sam deploy --guided

🧪 Local Development

Method 1: Using SAM Local API

# Start local API
sam local start-api

# Test endpoints using curl
curl http://localhost:3000/coins/list
curl http://localhost:3000/coins/bitcoin
curl http://localhost:3000/coins/bitcoin/history

Method 2: Using Postman Collection

1. Import the Postman collection:

   # Collection location
   docs/aws-sam-coin-lister.postman_collection.json

2. Set up environment variables in Postman:

   • baseUrl: http://localhost:3000 (for local testing)
   • prodUrl: https://{api-id}.execute-api.{region}.amazonaws.com/Prod (for production)

3. Available requests:

   • List All Coins: GET {{baseUrl}}/coins/list?page=1&per_page=100
   • Get Coin Details: GET {{baseUrl}}/coins/bitcoin
   • Get Coin History: GET {{baseUrl}}/coins/bitcoin/history

Method 3: Using Event Files

# Test with event file
sam local invoke ListCoinsFunction -e events/event.json

# Available test event
events/event.json           # List coins

🌐 API Endpoints

Endpoint	Method	Cache TTL	Description
/ping	GET	5 min	Health check endpoint
/coins/list	GET	30 min	List all coins with pagination
/coins/{coinId}	GET	5 min	Get specific coin details
/coins/{coinId}/history	GET	1 hour	Get coin price history

📝 Example Usage

# Health check
curl https://{api-id}.execute-api.{region}.amazonaws.com/Prod/ping

# List coins
curl https://{api-id}.execute-api.{region}.amazonaws.com/Prod/coins/list?page=1&per_page=100

# Get Bitcoin details
curl https://{api-id}.execute-api.{region}.amazonaws.com/Prod/coins/bitcoin

🛠️ Tech Stack

• 🟦 Serverless: AWS SAM, Lambda, API Gateway
• 💾 Cache: DynamoDB
• 📊 Data: CoinGecko API
• 🧪 Testing: Jest

📋 Prerequisites

• AWS Account & SAM CLI
• Node.js 18.x
• Docker (optional)
• Postman (optional, for API testing)

🧹 Cleanup

# Delete stack
sam delete

# Verify
aws cloudformation describe-stacks --stack-name sam-app

🔍 Troubleshooting

• Cache Errors: Normal during testing
• Deployment Issues: Check AWS credentials & IAM
• API Issues: Verify API ID & region

📝 Contributing

1. Fork & Clone
2. Create feature branch
3. Commit & Push
4. Create PR

📧 Contact

• GitHub
• LinkedIn
• Email

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🌟 Made with ❤️ by Ozer SUBASI