Single Lambda function what works with multiple S3 buckets to send SNS message

Use case

Recently I came across scenario where I had one Lambda Application which wanted to send event from respective S3 bucket to respective SNS topics.

S3-A ---->  Single Lambda-Application ----> SNS-A
S3-B ---->  Single Lambda-Application ----> SNS-B
S3-C  ---->  Single Lambda-Application ----> SNS-C

How to achieve this?

Step 1: Create a IAM Role

Attach both policies to IAM role for example LambdaSNSPublish

CWLogsPolicy.json
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "logs:CreateLogGroup",
                "logs:CreateLogStream",
                "logs:PutLogEvents"
            ],
            "Resource": "*"
        }
    ]
}
SNSPublish.json
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "sns:Publish"
            ],
            "Resource": "arn:aws:sns:*:*:*"
        }
    ]
}

Step 2: Create Lambda Function

Use above the IAM role while creating a Lambda function with Runtime Python

import json
import boto3
client = boto3.client('sns')
def lambda_handler(event, context):
    # TODO implement
    print((event))
    for record in event['Records']:
        if record['s3']['bucket']['name'] == '<BUCKET_NAME_1>':
            response = client.publish(
            TargetArn="<TOPIC_ARN_1>",
            Message=json.dumps({'default': json.dumps(event)}),
            MessageStructure='json')
            print(response)
        elif record['s3']['bucket']['name'] == '<BUCKET_NAME_2>':
            response = client.publish(
            TargetArn="<TOPIC_ARN_2>",
            Message=json.dumps({'default': json.dumps(event)}),
            MessageStructure='json')
            print(response)
        elif record['s3']['bucket']['name'] == '<BUCKET_NAME_3>':
            response = client.publish(
            TargetArn="<TOPIC_ARN_3>",
            Message=json.dumps({'default': json.dumps(event)}),
            MessageStructure='json')
            print(response)
return {
        'statusCode': 200,
        'body': json.dumps('Hello from Lambda!')
    }

Step 3: Configure Amazon S3 Event Notifications

Using the Amazon S3 console, add a notification configuration requesting Amazon S3 to:

Publish events of the All object create events type to your Amazon Lambda created in Step 2.

This will all allow you to send messages to respective SNS topics. You can restrict the Lambda function, S3 events, SNS topics as per the ARNs.