AWS Lambda | Overview & Hands-On.

AWS Lambda - Overview & Hands-On.

Scope:

• Intro,
• The concept:  AWS Lambda,
• Key Features,
• Common Use Cases,
• Supported Runtimes languages,
• Trigger Sources (Event Sources),
• Pricing (what twtech pays for),
• Sample Use Case- Auto Image Resizing with Lambda
• Deployment Options,
• Top Benefits of AWS Lambda,
• Project: Hands-On.

Intro:

• Here’s twtech overview of AWS Lambda, explained in a clear, beginner-friendly perspective,

 The concept:  AWS Lambda

• AWS Lambda is a serverless compute service from Amazon Web Services (AWS) that lets twtech to run code without provisioning or managing servers.
• twtech simply upload its code, set a trigger (like an API call or file upload), and AWS runs it for twtech.

 Key Features

Feature	Description
Serverless.	No need to manage servers or infrastructure
Event-driven.	Triggers can be S3 uploads, API calls, DynamoDB updates, cron jobs, etc.
Auto-scaling.	Automatically scales up/down with demand
Pay-per-use.	twtech pays only when your function is invoked (ms-based billing)
Stateless.	Functions don’t keep data between invocations (use S3, DynamoDB, etc.)
Short-lived executions.	Max run time per invocation: 15 minutes

Common Use Cases

Use Case	Description
API backend.	Build scalable APIs using API Gateway + Lambda
Image or video processing.	Process media on the fly after S3 uploads
Automation & cron jobs.	Scheduled tasks using EventBridge (CloudWatch Events)
IoT data processing.	React to IoT device messages in real time
Serverless websites.	Backend logic for static websites hosted on S3 + CloudFront
Data transformation.	ETL (Extract, Transform, Load) operations in data pipelines

 Supported Runtimes languages:

• Python
• Node.js
• Java
• Go
• .NET Core (C#) & / Powershell 
• Ruby
• Custom runtimes (e.g., Rust, PHP, etc. via Lambda layers)

 Trigger Sources (Event Sources)

Source	Example
Amazon S3.	File uploaded → run Lambda to process the file
API Gateway.	HTTP request → run Lambda to return response
EventBridge.	Scheduled cron job → run Lambda daily/hourly
DynamoDB Streams.	New DB item → run Lambda to process it
SNS / SQS.	Message received → run Lambda

 Pricing (what twtech pays for):

1. Number of invocations (first 1M/month = free)
2. Execution time (based on memory & duration)

Example:

•  A function that runs for 1 second using 128MB RAM = ~$0.000000208 per execution.

 Sample Use Case- Auto Image Resizing with Lambda:

1. User uploads an image to S3.
2. That triggers a Lambda function.
3. Lambda resizes the image and stores the result in another S3 bucket.

NB:

• No servers is required, 
• No manual scaling is needed. 
• Just write the code and it runs when needed.

 Deployment Options

• Use the AWS Console (web UI)
• Use AWS CLI or SAM (Serverless Application Model)
• Use frameworks like:
• Serverless Framework
• Terraform
• CDK (Cloud Development Kit)

Top Benefits of AWS Lambda

• Here are the top benefits of using AWS Lambda, especially when twtech is looking for: 
• Efficiency, 
• Scalability,
• Lower operational overhead.

1. No Server Management (Serverless)

• twtech doesn’t have to manage, patch, or scale servers.
• AWS handles the entire infrastructure for you.

 NB:

• Great for developers — twtech focuses on twtech code.

2. Automatic Scaling

• Lambda automatically handles scaling up or down based on the number of incoming events or requests.
• Whether twtech has 10 or 10,000 requests per second, Lambda adjusts instantly.

3. Pay Only for What twtech Uses

• No idle time billing — you pay only when your code runs.
• Pricing is based on:
• Number of requests
• Execution duration
• Memory allocation

 NB:

• twtech Can save a lot of money compared to always-on EC2 instances.

4. Event-Driven

• Lambda integrates natively with many AWS services:
• S3 (file upload triggers)
• DynamoDB (stream triggers)
• API Gateway (web/API requests)
• CloudWatch/EventBridge (scheduled events)
• SNS/SQS (messaging queues)

 NB:

• Great for automation, real-time processing, and reactive systems.

5. High Availability & Fault Tolerance

• Lambda functions are run across multiple Availability Zones by default.
• AWS automatically ensures reliability and redundancy.

 NB:

• No extra configuration needed to make it highly available.

6. Easy Deployment

• Code can be uploaded directly or via deployment tools (CLI, SAM, CDK).
• Supports versioning and aliases for safe deployments and rollbacks.

7. Multiple Language Support

• Writes twtech functions in:
• Python
• Node.js
• Java
• Go(Golang)
• C# (.NET Core)
• Ruby
• Or even custom runtimes

 NB:

• Supports flexibility for different tech stacks.

8. Secure by Design

• Integrated with IAM (Identity and Access Management)
• twtech can define fine-grained permissions for what its Lambda function can access.

 NB:

• Ensures least-privilege access and better security posture.

9. Granular Monitoring & Logging

• Integrated with Amazon CloudWatch for:
• Logs
• Metrics
• Alerts

NB:

• Helps in easy debugging and performance tuning.

10. Faster Time to Market

• With less time spent on infrastructure, you can focus on building features quickly.
• Ideal for startups, prototypes, MVPs (Minimum Viable Products), and microservices.

 NB:

• It Speeds up development cycles and iterate faster.

Project: Hands-On

• How twtech creates and use AWS Lambda for Resources.

Search for aws service: Lambda.

Create a function:

Next 

• twtech accesses events: Lambda responds to events

• How Lambda Function works:

NB:

• Scaling up lambda function is automatic: by clicking on any of input sources

• Next twtech needs to: Scale seamlessly

• Next: create a function

Create function
twtech needs to Choose one of the following options to create its function

• Architecture
• twtech Chooses the instruction, then set architecture it wants for its function code.

• Change default execution role or create one

Additional configurations

• Use additional configurations to set up code signing, function URL, tags, and Amazon VPC access for twtech function.

• twtech tests the function created: twtech-app-function

• Test function:

• Execution successful:

• twtech checks the details of the function executed:

• twtech saves the lambda events:

• twtech monitors its Lambda function: twtech-app-function

• CloudWatch logs can also be viewed: For Observability

• Accessing logs streams:

•  twtech sets general configuration of its Lambda function.

• Edit basic settings

• Save changes:

• How to view basic Lambda role execution:

• How twtech views roles created for Lambda function: Permissions(roles) can be edited

• View role document:twtech-app-functon-role-document

• How twtech added triggers to its Lambda Function:

• Select the : Triggers and add