ตัวกระตุ้นเหตุการณ์ S3 และ SQS

Serverless functions, like AWS Lambda, don't just run on their own. They wait for something to happen! This "something" is called an event.

An event is a signal from another service that tells your Lambda function to execute. Think of it like a doorbell ringing for your function to answer.

Amazon S3 (Simple Storage Service) is a popular cloud storage service. It can generate events when objects are created, deleted, or modified in your buckets.

• Object Created (PUT): An image is uploaded.
• Object Deleted: A file is removed.
• Object Restored: An archived item is brought back.

These events can trigger a Lambda function to process the changes.

To link an S3 bucket to a Lambda function, you define a trigger. This tells S3 which events to listen for and which Lambda function to invoke.

• You specify the S3 bucket.
• You choose the event types (e.g., s3:ObjectCreated:*).
• You can filter by object prefix or suffix (e.g., only trigger for images/ folder or .jpg files).

When an S3 event triggers your Lambda function, the function receives a JSON object containing details about the event. This object is the "event" parameter in your function handler.

Key information includes:

• Bucket Name: Where the event occurred.
• Object Key: The full path and name of the file affected.
• Event Name: The specific action (e.g., ObjectCreated:Put).

Here's a Python Lambda function that processes an S3 object creation event. It extracts and prints the bucket name and the key of the uploaded object.

Try uploading a file to an S3 bucket configured to trigger this function!

Amazon SQS (Simple Queue Service) is a message queuing service. It allows different parts of your application to communicate asynchronously without direct interaction.

When messages are sent to an SQS queue, they can trigger a Lambda function. This is great for tasks that can be processed later or in batches, like sending emails or processing orders.

Setting up an SQS trigger for Lambda is straightforward. Lambda continuously polls the SQS queue for new messages.

• You specify the SQS queue.
• You define a batch size (1 to 10,000 messages). This determines how many messages Lambda tries to process in a single invocation.
• Lambda deletes messages from the queue only after successful processing.

Similar to S3, an SQS event passed to your Lambda function is a JSON object. It contains an array of Records, each representing a message from the queue.

Each record includes:

• Message Body: The actual content of the message.
• Message Attributes: Optional metadata about the message.
• Receipt Handle: Used internally by SQS for message deletion.

This Python Lambda function processes messages from an SQS queue. It iterates through the batch of messages received and prints their content.

Imagine each message contains a task to perform!

You've learned about two powerful event sources for AWS Lambda: S3 and SQS. They serve different purposes but both enable event-driven architectures.

Which of the following statements are TRUE regarding S3 and SQS Lambda triggers?

Great job! You've explored how AWS Lambda functions can be triggered by events from Amazon S3 and SQS.

• S3 triggers are perfect for reacting to file changes, like image uploads or document processing.
• SQS triggers enable asynchronous processing of messages, allowing for decoupled and scalable workflows.

These event sources are fundamental to building powerful, reactive serverless applications!