AWS S3 Object Lambda

1. Introduction

AWS S3 Object Lambda is a feature that allows you to add your own processing to S3 GET requests. This enables you to customize the data returned to your applications without changing how your applications retrieve data from S3.

2. Key Concepts

• S3 Object Lambda: A method to transform S3 object data at retrieval time.
• Lambda Function: A serverless function that processes the data as per your defined logic.
• Access Points: Simplified access management for S3 data, allowing you to define different access policies.

3. Setup Steps

1. Create an S3 Bucket.
2. Define an Access Point for your S3 bucket.
3. Create a Lambda function that defines how to transform your S3 object data.
4. Configure S3 Object Lambda to use your Lambda function.
5. Test your setup by making a GET request to the S3 Object Lambda endpoint.

4. Code Example

const AWS = require('aws-sdk');
const s3 = new AWS.S3();

exports.handler = async (event) => {
    const bucket = event.Records[0].s3.bucket.name;
    const key = decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, ' '));

    const params = {
        Bucket: bucket,
        Key: key,
    };

    try {
        const { Body } = await s3.getObject(params).promise();
        const transformedData = Body.toString('utf-8').toUpperCase(); // Example transformation
        return {
            statusCode: 200,
            body: transformedData,
        };
    } catch (error) {
        console.error(error);
        return {
            statusCode: 500,
            body: error.message,
        };
    }
};

5. Best Practices

• Minimize the size of the data returned to reduce latency.
• Implement error handling in your Lambda function to manage exceptions.
• Log your Lambda function's execution for debugging and monitoring.

6. FAQ