Serverless Application > Preparation Steps > Create and Write Lambda Functions

Create and Write Lambda Functions

In this step, we will create a data table in DynamoDb.

Use the search bar to find the Lambda service, go to Function, and select Create Function.

Create Function

Name the function, set the Runtime to Python 3.12, and Architecture to x86_64.

Create Function Step 2

In the Permission section, choose Use an existing role, and select the role you created in step 2.1.

Create Function Step 3

After creating the function, wait for the code editor to be set up.

Create Function Step 4

Write the code for the getStudentData function as follows:

import json
import boto3

def lambda_handler(event, context): 
    # Initialize a DynamoDB resource object for the specified region
    dynamodb = boto3.resource('dynamodb', region_name='us-east-1')

    # Select the DynamoDB table named 'studentData'
    table = dynamodb.Table('studentData')

    # Scan the table to retrieve all items
    response = table.scan()
    data = response['Items']

    # If there are more items to scan, continue scanning until all items are retrieved
    while 'LastEvaluatedKey' in response:
        response = table.scan(ExclusiveStartKey=response['LastEvaluatedKey'])
        data.extend(response['Items'])

    # Return the retrieved data
    return data

In the line dynamodb = boto3.resource(‘dynamodb’, region_name=‘us-east-1’), replace us-east-1 with the region where your AWS account is located. My account is in the N. Virginia region, so I use us-east-1. After adjusting, click Deploy to deploy the function.

Create Function Step 5

Repeat steps 1 to 4 to create another function named insertStudentData, and use the following code:

import json
import boto3

# Create a DynamoDB object using the AWS SDK
dynamodb = boto3.resource('dynamodb')
# Use the DynamoDB object to select our table
table = dynamodb.Table('studentData')

# Define the handler function that the Lambda service will use as an entry point
def lambda_handler(event, context):
    # Extract values from the event object we got from the Lambda service and store in variables
    student_id = event['studentid']
    name = event['name']
    student_class = event['class']
    age = event['age']
    
    # Write student data to the DynamoDB table and save the response in a variable
    response = table.put_item(
        Item={
            'studentid': student_id,
            'name': name,
            'class': student_class,
            'age': age
        }
    )
    
    # Return a properly formatted JSON object
    return {
        'statusCode': 200,
        'body': json.dumps('Student data saved successfully!')
    }