lambda-exchange-tracker

Codebase for Lambda-based Currency Exchange application

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• Backend Server: AWS Lambda - Serverless Infrastructure

• python3.11
• Curated requirements.in [basic dependency libs]
• Design Pattern followed: Creational-Singleton and Structural-Decorator Design Pattern
• Architecture: Event-Driven Asynchronous Architecture

1. Steps for executing and hosting of application locally

Installation Guide for LocalStack support ecosystem

Installation Guide: https://docs.localstack.cloud/getting-started/installation/

Initiating the Localstack application server

localstack start # initialize

2. To setup the required AWS services locally via IaC and CDK

sudo chmod +x run_executor.sh
Run the command: /bin/bash run_executor.sh

3. Login to LocalStack Web-App to visualize the initiated services

Navigate to: `https://app.localstack.cloud/dashboard`

4. Architectural Design - Business Logic

• Cloudwatch EventBridge
  • Event Rule defined to periodically trigger Lambda action to scrape the Currency Conversion (daily basis).
  • Once scraped, evaulate the fluctuated spot rate for enlisted currency for exchange and stored as time-series documents (NoSQL schema).

• API Gateway Resources
  • Publically exposed GET method to fetch the Currency Spot Rate and Fluctuations for enlisted currencies.
  • API Gateway service, being hosted on https://localhost.localstack.cloud:4566 domain to emulate the AWS ecosystem.
  • Public Endpoint: http://localhost:4566/_aws/execute-api/\<apiId>/dev/api/v1/kaizen/fetch-currency-exchange/generate

5. Manual Modular Testing

• As to perform Modular Testing, execute the inline command: python3 worker_lambda.py
  • For EventBridge moderation: report_generation_cron_event as placeholder value
  • For APIGateway moderation: api_currency_exchange_event as placeholder value
• Code Snippet:

  • class Context:
    

        invoked_function_arn = "test:dev"

        print(
            async_lambda_handler(
                event=events.api_currency_exchange_event, context=Context()
            )
        )

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