การผสานรวม Lambda กับ API Gateway

Welcome! In this lesson, you'll learn how to link your AWS Lambda functions to API Gateway. This creates a powerful serverless HTTP endpoint, letting users trigger your code via web requests.

Think of it as giving your Lambda function a web address!

Remember, API Gateway acts as the front door for your serverless applications. It handles incoming HTTP requests and routes them to the correct backend service, like a Lambda function.

• Manages traffic efficiently
• Handles authentication and authorization
• Routes requests to specific functions

The most common and flexible way to connect API Gateway to Lambda is using Lambda Proxy Integration. This method passes the entire incoming HTTP request to your Lambda function.

Your Lambda then processes the request and returns a specific JSON response that API Gateway understands.

With proxy integration, API Gateway sends the full HTTP request (headers, body, query parameters) to your Lambda as an event object.

Your Lambda must return a JSON object with specific keys: statusCode, headers, and body. This allows API Gateway to craft the final HTTP response for the client.

Let's write a simple Python Lambda function that expects a proxy event. It will return a 'Hello from Lambda!' message and echo back part of the input.

Remember, the event dictionary contains all request details.

Now, let's set up the API Gateway part. We'll create an HTTP API and define a route.

HTTP APIs are simpler and more cost-effective for basic serverless endpoints compared to REST APIs. We covered the differences in a previous lesson.

In API Gateway, you'll create a route, for example, GET /hello. This route specifies the HTTP method and path for your endpoint.

Then, you'll add an integration to this route, pointing it to your Lambda function. This is where API Gateway knows which Lambda to invoke!

For API Gateway to successfully trigger your Lambda function, it needs permission. This is managed by an IAM Role associated with API Gateway.

Specifically, API Gateway requires the lambda:InvokeFunction permission on your Lambda resource. AWS often sets this up automatically when integrating via the console.

After configuring the route and integration, you need to deploy your API Gateway changes. This makes your endpoint publicly accessible.

You'll get an invoke URL, which you can use with tools like a web browser or curl to test your new serverless API!

You've learned how Lambda Proxy Integration works. Which of the following are REQUIRED in the JSON response from a Lambda function for API Gateway Proxy Integration?

Great job! You've learned how to integrate Lambda functions with API Gateway:

• API Gateway acts as the web front door for your serverless functions.
• Lambda Proxy Integration is the standard method, passing full HTTP requests to Lambda.
• Lambda returns a specific JSON format (statusCode, headers, body) for API Gateway to process.
• IAM permissions are crucial for API Gateway to invoke your Lambda function securely.
• After deployment, your Lambda function is accessible via a public URL!