AWS Lambda function to keep historical data for a table

DynamoDBHistoricalData.py

from __future__ import print_function

import json
import boto3
import datetime

dynamodb = boto3.resource('dynamodb', region_name='ap-southeast-1')

table = dynamodb.Table('TableNameHistory')

def lambda_handler(event, context):

    print("Received event: " + json.dumps(event, indent=2))
    
    for record in event['Records']:
        
        item = {str(key): str(val['S']) for key, val in record['dynamodb']['NewImage'].items()}
        item['ApproximateCreationDateTime'] = record['dynamodb']['ApproximateCreationDateTime']
        response = table.put_item(Item=item)
        
    return 'Successfully processed {} records.'.format(len(event['Records']))

The table should be created with the same Partition Key as the original table, and a numerical sort key of 'ApproximateCreationDateTime'

ApproximateCreationDateTime can be converted to datetime downstream with:

import datetime

epoch = datetime.datetime.utcfromtimestamp(ApproximateCreationDateTime)