AWS - how to pass DynamoDb table data to Lambda function - amazon-web-services

Question

Below is my customer table in DynamoDb
name: string
I have linked a trigger that would call Lambda function that in turn calls my app Endpoint which would do data transformation & save in SQL DB
Whenever I am adding any record or updating record in the above table, I can see that Lambda function is getting called. but not sure how can I capture the table data.
I need to capture the name value of the customer dynamoDb table via Lambda function which I can pass to my Endpoint.
Newbie to this. So please excuse if it's too simple. But couldn't find the info that could drive this for me.
Thanks!

Answer 1

You Lambda function will receive a DynamoDB Streams Record Event (see Using AWS Lambda with Amazon DynamoDB for an example event).
You are going to map/loop over the Records key where you will find objects with eventName: INSERT. Inside the dynamodb key you will find the table data that you should process in your Lamdba function's code.
{
"Records": [
{
"eventID": "1",
"eventVersion": "1.0",
"dynamodb": {
"Keys": {
"Id": {
"N": "101"
}
},
"NewImage": {
"Message": {
"S": "New item!"
},
"Id": {
"N": "101"
}
},
"StreamViewType": "NEW_AND_OLD_IMAGES",
"SequenceNumber": "111",
"SizeBytes": 26
},
"awsRegion": "us-west-2",
"eventName": "INSERT",
"eventSourceARN": eventsourcearn,
"eventSource": "aws:dynamodb"
}
]
}
In your case, the data should be located at Records[0].dynamodb.NewImage.name.S
If working with Node.js and mixed types in your table, I suggest using AWS.DynamoDB.Converter.unmarshall which converts a DynamoDB record into a JavaScript object. It allows you to do something like this:
const newImage = DynamoDB.Converter.unmarshall(event.Records[0].dynamodb.NewImage);