Typical event sources that trigger Lambda functions - 3.4.3 | Chapter 3: Deep Dive into Compute Services | AWS Basic
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3.4.3 - Typical event sources that trigger Lambda functions

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Interactive Audio Lesson

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Introduction to AWS Lambda

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0:00
Teacher
Teacher

Let's start our session by understanding what AWS Lambda is. Can anyone tell me what you think Lambda does?

Student 1
Student 1

It's a serverless computing service that runs code without managing servers, right?

Teacher
Teacher

Exactly! AWS Lambda lets you run code in response to events. What kind of events do you think can trigger these actions?

Student 2
Student 2

Maybe when a file is uploaded or something changes?

Teacher
Teacher

Great points! We often think of event sources like S3 file uploads or changes in DynamoDB. Let's remember: S3 for storage. Can anyone create a mnemonic for that?

Student 3
Student 3

How about 'S3 Saves Stuff'?

Teacher
Teacher

I love it! So what else might trigger a Lambda function? Any other ideas?

Student 4
Student 4

HTTP requests through API Gateway?

Teacher
Teacher

Yes, perfect! You all are doing great. Remember, API Gateway is a door for your Lambda functions to receive HTTP calls!

Event Sources - Deep Dive

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0:00
Teacher
Teacher

Let’s dive deeper into each event source. What happens when you upload a file to S3?

Student 1
Student 1

It can trigger a Lambda function to process the file?

Teacher
Teacher

Exactly! This can be used to create thumbnails or extract metadata. Now, can someone explain changes in a DynamoDB table?

Student 3
Student 3

Whenever there's an insert or update, it triggers a Lambda function to keep the data consistent.

Teacher
Teacher

Well stated! What about the role of API Gateway in this process?

Student 4
Student 4

It routes HTTP requests to Lambda, allowing applications to interact with AWS services.

Teacher
Teacher

Correct again! API Gateway can create RESTful APIs for triggering Lambda functions. Lastly, what are scheduled events?

Student 2
Student 2

Like cron jobs that run functions at specific times!

Teacher
Teacher

Nice! Scheduled events help in executing Lambda functions automatically. In summary, can someone recap the four event sources we've covered?

Student 1
Student 1

S3 uploads, DynamoDB changes, API Gateway requests, and scheduled events!

Teacher
Teacher

Great summary! You all are really grasping this concept!

Introduction & Overview

Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.

Quick Overview

This section covers the common event sources that can trigger AWS Lambda functions, demonstrating the ease of responding to various data-driven events in a serverless architecture.

Standard

AWS Lambda is a serverless computing service that executes code in response to specific triggers. This section discusses typical event sources such as file uploads to Amazon S3, changes in DynamoDB, HTTP requests through API Gateway, and scheduled events, illustrating how Lambda handles these events efficiently without the need for server management.

Detailed

Typical Event Sources in AWS Lambda

AWS Lambda enables developers to run code in response to various events without the need to manage servers. This functionality is triggered by several typical event sources, allowing developers to build efficient and responsive applications. The key event sources include:

  1. Amazon S3: Anything as simple as uploading a file can trigger a Lambda function. For instance, upon image upload, Lambda can process or store the image in another format.
  2. DynamoDB: Changes within a DynamoDB table (like inserts or updates) can invoke a Lambda function to ensure data consistency across applications or services.
  3. API Gateway: HTTP requests made through the API Gateway can signal Lambda to execute code, integrating AWS services and applications seamlessly.
  4. Scheduled Events: Similar to traditional cron jobs, Lambda functions can be scheduled to run at specific intervals using AWS CloudWatch.

The ability to leverage these event sources effectively allows developers to create responsive, automated workflows without server overhead, making AWS Lambda a central utility in serverless computing.

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Example Use Case of Lambda

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Example Use Case:
Suppose you want to automatically generate thumbnails for images uploaded to S3:
1. Upload an image to an S3 bucket.
2. This triggers a Lambda function.
3. Lambda processes the image and saves the thumbnail back to S3.
4. No need to manage servers or scale manuallyβ€”Lambda handles everything.

Detailed Explanation

Let's consider an example where you want to create a thumbnail version of an image as soon as it's uploaded to your Amazon S3 bucket. The steps are as follows:

  1. Upload an image: You or a user uploads a high-resolution image to the S3 storage.
  2. Triggers a Lambda function: This upload acts as an event that automatically triggers a pre-configured Lambda function designed for image processing.
  3. Lambda processes the image: The Lambda function executes the code to resize the uploaded image to create a thumbnail, suitable for displaying in an online gallery.
  4. Saves back to S3: Finally, the generated thumbnail is saved back in another S3 bucket or a specific location in the original bucket.
  5. Server management: The power of using Lambda here is that you don’t have to worry about managing the server that runs this image processing code. AWS takes care of running, scaling, and maintaining it efficiently.

Examples & Analogies

Imagine you're running a popular coffee shop that has an online ordering system. When a customer orders a coffee, you don’t need to call your barista every timeβ€”there's a machine that automatically prepares the coffee as soon as the order is placed. In this analogy, the order placed is like uploading an image to S3, the machine is your Lambda function, and the prepared coffee represents the thumbnail created. Just as the machine autonomously prepares coffee without needing staff for every order, Lambda autonomously generates thumbnails without needing you to manage servers.

Definitions & Key Concepts

Learn essential terms and foundational ideas that form the basis of the topic.

Key Concepts

  • Event Sources: Triggers that initiate Lambda functions, including S3 uploads, DynamoDB changes, API Gateway requests, and scheduled events.

  • Serverless Computing: A model where the cloud provider manages the infrastructure, allowing developers to focus on code.

Examples & Real-Life Applications

See how the concepts apply in real-world scenarios to understand their practical implications.

Examples

  • When a user uploads a new photo to an S3 bucket, it can trigger a Lambda function to generate a thumbnail or process the image.

  • A new entry in a DynamoDB table can automatically invoke a Lambda function to update other systems or log changes.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎡 Rhymes Time

  • When you upload to S3, Lambda will process so blissfully!

πŸ“– Fascinating Stories

  • Imagine a chef (Lambda) waiting for orders (events) from different sources (S3, DynamoDB) to serve dishes (executing code) at the right time.

🧠 Other Memory Gems

  • Remember 'SADPS' for sources: S3, API Gateway, DynamoDB, Scheduled events.

🎯 Super Acronyms

Use 'LASER' to recall Lambda event sources

  • L: for Lambda
  • A: for API Gateway
  • S: for S3
  • E: for events
  • R: for responses.

Flash Cards

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Glossary of Terms

Review the Definitions for terms.

  • Term: AWS Lambda

    Definition:

    A serverless compute service that allows running code in response to events without provisioning or managing servers.

  • Term: Amazon S3

    Definition:

    Simple Storage Service, an object storage service that stores data in buckets.

  • Term: DynamoDB

    Definition:

    A fully managed NoSQL database service that provides fast and predictable performance.

  • Term: API Gateway

    Definition:

    A service for creating, publishing, maintaining, monitoring, and securing REST, HTTP, and WebSocket APIs.

  • Term: Scheduled Events

    Definition:

    Events that trigger Lambda functions at specified time intervals, similar to cron jobs.