AWS Compute + Database + Storage - Lambda + DynamoDB + S3 Bucket

 

Lambda with S3 Example

1. Configure security - Role

Create a DynomdbFullAccess Role and Assign to Lambda (NOT EC2!!).

             AmazonDynamoDBFullAccess

2. Configure a Lambda Function

Step 1: Create a Lambda function Func2 with Runtime as Python 3.6

Step 2: Write below code in the code window. (This code is written in python using Boto Library which has the functions to insert S3 object information into DynamoDB table).

import boto3

from uuid import uuid4

def lambda_handler(event, context):

    s3 = boto3.client("s3")

    dynamodb = boto3.resource('dynamodb')

    for record in event['Records']:

        bucket_name = record['s3']['bucket']['name']

        object_key = record['s3']['object']['key']

        size = record['s3']['object'].get('size', -1)

        event_name = record ['eventName']

        event_time = record['eventTime']

        dynamoTable = dynamodb.Table('newtable-irfan')

        dynamoTable.put_item(

            Item={'unique': str(uuid4()), 'Bucket': bucket_name, 'Object': object_key,'Size': size, 'Event': event_name, 'EventTime': event_time})

Step 3: File---> Save and Click on the Deploy button.

Step 4: Click on Configuration Tab and select Permission and click on Edit Role and attach the role which is created on Step1.

Step 5: Add Trigger by clicking on Add trigger button.

          Select S3 trigger

          Select bucket name (if you don't have a bucket, create a bucket first)

          Event Type: All objects create events

          Select acknowledgment for recursive invocation.

          Click on Add button

3. Initiate a DynamoDB Table

Step 1: Create a DynamoDB table newtable-irfan and partition key unique.

Step 2: Explore items in newtable-irfan and you will find no records for this table.

4. Monitor changes in DynamoDB when you upload something in S3 bucket

Step 1: Upload and file in S3 bucket.

Step 2: Explore items in the DynamoDB table. and you will find the metadata information of the uploaded file in the S3 bucket.

Experiment:

Notice that if you delete the file in S3 bucket, the data in dynamoDB will not be erased.

Why?

because the lambda function we provide is only doing the PUT method. if we want to delete from the dynamoDB, we need to make another method. BUT that will require the API GATEWAY!.