What is a Lambda function handler?
A Lambda function handler is the entry point for your AWS Lambda function. It's the method or function that AWS Lambda invokes when executing your code. The handler processes the input event and returns a response. Its structure and signature depend on the programming language runtime you're using.
Key Characteristics of a Lambda Handler
Defined in the format
fileName.functionName(e.g.,index.handler)Receives two arguments:
event(input data) andcontext(metadata)Must be exported or publicly accessible, depending on the language
Should return a response or promise (async) in supported runtimes
Handles any initialization or cleanup tasks inside the function body
Example of a Node.js Lambda Handler