Create the DynamoDB global Table if doesn't exist using Cloudformation - amazon-web-services

Question

I am sharing the DynamoDB cft below. I want to add a condition, so that while adding the another table the existing tables will not impact. Below template is used for creating 2 global table with name as sample1 and sample12 configuring in parameter section:
AWSTemplateFormatVersion: "2010-09-09"
Description: 'AWS CloudFormation Template for DynamoDB tables For sample Service'
Parameters:
sample1:
Type: String
Description: Select existing dynamodb table name from Parameter Store
Default: sample1
sample12:
Type: String
Description: Select existing dynamodb table name from Parameter Store
Default: sample12
Resources:
sample1:
Type: AWS::DynamoDB::GlobalTable
Properties:
BillingMode: PAY_PER_REQUEST
AttributeDefinitions:
-
AttributeName: "msgId"
AttributeType: "S"
KeySchema:
-
AttributeName: "msgId"
KeyType: "HASH"
StreamSpecification:
StreamViewType: NEW_AND_OLD_IMAGES
SSESpecification:
SSEEnabled: true
SSEType: "KMS"
Replicas:
- Region: us-east-1
TableName: !Ref sample1
sample12:
Type: AWS::DynamoDB::GlobalTable
Properties:
BillingMode: PAY_PER_REQUEST
AttributeDefinitions:
-
AttributeName: "msgId"
AttributeType: "S"
-
AttributeName: "flightNbr"
AttributeType: "S"
-
AttributeName: "recordUpdateTS"
AttributeType: "S"
-
AttributeName: "msgTypeCd"
AttributeType: "S"
-
AttributeName: "recordCreationEpochTime"
AttributeType: "S"
KeySchema:
-
AttributeName: "msgId"
KeyType: "HASH"
StreamSpecification:
StreamViewType: NEW_AND_OLD_IMAGES
SSESpecification:
SSEEnabled: true
SSEType: "KMS"
Replicas:
- Region: us-east-1
TableName: !Ref sample12
GlobalSecondaryIndexes:
-
IndexName: "FLIGHTNBR_UPDATETS_INDEX"
KeySchema:
-
AttributeName: "flightNbr"
KeyType: "HASH"
-
AttributeName: "recordUpdateTS"
KeyType: "RANGE"
Projection:
ProjectionType: "ALL"
-
IndexName: "MSGTYPE_CREATETS_INDEX"
KeySchema:
-
AttributeName: "msgTypeCd"
KeyType: "HASH"
-
AttributeName: "recordCreationEpochTime"
KeyType: "RANGE"
Projection:
ProjectionType: "ALL"
How can I add a condition or any other methods to check if table exists or not?

Answer 1

The only way to do this is through custom resource in the form of a lambda function. The function would use AWS SDK to perform conditional checks and create aws resources based on the outcome of these checks.