Introduction to AWS Lambda

AWS Lambda is a serverless compute service provided by Amazon Web Services. It allows developers to run code without having to provision or manage servers, thus reducing the overhead and enabling rapid scaling. Lambda automatically scales and executes your code in response to triggers such as changes in data, shifts in system states, or specific HTTP requests.

Storing Secrets for External APIs

When building Lambda functions that interact with external APIs, it’s crucial to manage sensitive information such as API keys or credentials securely. These secrets should not be hardcoded in your Lambda function code. Instead, AWS offers several ways to securely manage such information, ensuring your applications remain secure while maintaining high performance.

AWS Secrets Manager

AWS Secrets Manager is a service designed specifically for managing secrets. It simplifies the process of maintaining and using these secrets within Lambda functions.

How to Use Secrets Manager with AWS Lambda

1. Store Your Secret:
   • Navigate to the AWS Secrets Manager in the AWS Management Console.
   • Click on "Store a new secret."
   • Choose the type of secret (e.g., API key or login credentials).
   • Enter the secret information.
   • Name your secret and complete the process.
2. Accessing Secrets in Lambda:
   • Grant your Lambda function permissions to access the secret:
     • Attach a policy to the Lambda execution role allowing access to the Secrets Manager.
   • Retrieve the secret within the Lambda function using AWS SDK:
   • Navigate to the AWS Systems Manager in the AWS Management Console.
   • Choose "Parameter Store" and then "Create parameter."
   • Enter a name for your parameter and add your secret as a "SecureString" type.
   • Update your Lambda execution role with permissions to access the Parameter Store:
   • Retrieve the parameter in your Lambda function using AWS SDK:
   • Only store non-sensitive configuration data in environment variables. They could be misconfigured or exposed unintentionally.
   • Enable logging and monitoring to track access to secrets for compliance and auditing purposes.
   • Always adhere to the principle of least privilege. Only grant permissions that are absolutely necessary for your Lambda function to operate.
   • Fetching secrets involves network calls which can add latency. Always consider caching secrets within the execution context after initial retrieval.