CDK TypeScript: Conditional Creation of DynamoDB Table

To implement conditional creation of a DynamoDB table in AWS CDK using TypeScript, you can use a combination of the TableV2 construct and the fromTableName method. Here's an approach you can take:

1. First, use the TableV2.fromTableName method to attempt to reference an existing table. This method creates a reference to an existing table without actually creating a new one.

2. If the table doesn't exist, this reference will be undefined, and you can then create a new table using the TableV2 construct.

Here's an example of how you might implement this:

import * as dynamodb from 'aws-cdk-lib/aws-dynamodb';
import * as cdk from 'aws-cdk-lib';

// ... in your stack definition

const tableName = 'YourTableName';

// Try to reference an existing table
const existingTable = dynamodb.TableV2.fromTableName(this, 'ExistingTable', tableName);

let table: dynamodb.TableV2;

if (existingTable === undefined) {
  // Table doesn't exist, create a new one
  table = new dynamodb.TableV2(this, 'NewTable', {
    tableName: tableName,
    partitionKey: { name: 'id', type: dynamodb.AttributeType.STRING },
    removalPolicy: cdk.RemovalPolicy.RETAIN,
    // ... other table properties
  });
} else {
  // Table exists, use the reference
  table = existingTable;
}

// Now you can use 'table' in the rest of your stack

This approach allows you to conditionally create the table or reference an existing one. The fromTableName method will not throw an error if the table doesn't exist, it will simply return undefined.

Remember that when you're referencing an existing table, you won't be able to modify its properties through CDK. Any changes to the table structure would need to be done outside of this stack.

Also, keep in mind that this approach doesn't guarantee atomicity. There's a small chance that the table could be created between the check and the creation step. If this is a concern, you might need to implement additional error handling or use a more robust strategy.

Lastly, ensure that your IAM permissions allow for describing DynamoDB tables, as the fromTableName method will attempt to describe the table to check its existence.

Sources
aws-cdk-lib.aws_dynamodb module · AWS CDK
CDK Typescript check if S3 already exists | AWS re:Post