AWS Classroom Series – 25/Feb/2021

Microservices – do onething and do it well

• Microservices focus more on decoupling an application, and the communication mechanism is lightweight and typically http.
• Large complex applications can be broken down into components with bounded context to build a generic service.
• Application like ecommerce can be broken down into multiple microservices such as
  • User signup
  • Inventory
  • Order Management
  • Order Tracking Management
  • Invoice Generator
• Docker containers and Orchestration tools like k8s are very popular over here.

Nano Services

• Nano services helps in breaking down microservcies into operations.
• This is where the serverless technologies like AWS Lambda/Azure functions can be very handy.

Prereq’s for AWS Lambda

• Ensure AWS CLI is installed Refer Here

AWS Lambda Basics

• Function:
  • this is piece of your own code that executes every time it is triggered by an event.
  • This function can be written in different programming languages. Refer Here for the specific versions of the runtimes
    • Node js
    • Python
    • Ruby
    • Java
    • Go
    • C#
    • Powershell

Anatomy of Lambda function

• Handler function: This is entry point for all Lambda functions. Whenever the function executes, the service calls the handler function and passes in some event data and useful objects
• Node Js

exports.handler = function(event, context, callback) {
    callback(null, 'executed succesfully')
}

• Python

def handler(event, context):
    return "executed successfully"

• C#:

public string Handler(string input, ILambdaContext context) {
    return "executed successfully";
}

• Java:

public String handler(InputStream inputStream, OutputStream outputStream, Context context) {
    return "executed Successfully";
}

• Context object in python has the following structure Refer Here

Lets install Boto3

• Install python Refer Here
• Install boto3 Refer Here
• Boto3 is python sdk to communicate with AWS
• Refer Here for the changeset

Java AWS SDK

• Refer Here
• Refer Here for setting up the Java SDK

Next Steps:

• We will write aws lambda function to shutdown all the ec2 instances