[aws-dynamodb] Creating a new Table using fromTableName returns a Table object that doesn't include secondary indexes

Hello!

I’ve noticed some discrepancies between the behavior of a dynamodb.Table created as new Table() and ones that are created by using Table.fromTableName()

Using new Table(...).grantReadWriteData(myLambdaFunction) delegates permissions to the primary table index, alongside all available GSIs.

However, using new Table.fromTableName(…).grantReadWriteData(myLambdaFunction) seems to delegate permissions to the primary table index only.

Reproduction Steps

const table = new Table.fromTableName(this, TABLE_NAME, TABLE_NAME).grantReadWriteData(
  myLambdaFunction
);

table.grantReadWrite(lambdaFn);

What did you expect to happen?

Lambda function should be granted permissions to ReadWrite to all of the table’s indexes, both primary and LSIs/GSIs.

What actually happened?

Lambda function was granted permissions to ReadWrite to the primary index only.

Environment

• CDK CLI Version : 1.69.0
• Framework Version: 1.69.0
• Node.js Version: 12.9.0
• OS : Linux
• Language (Version): TypeScript 3.6.4

Other

To workaround this issue one could explicitly define all partitions and then grant the necessary permissions to each, as such:

const primaryIndex = Table.fromTableName(this, "MyTable", "MyTable");

const secondaryIndex = Table.fromTableName(
  this,
  `MyTableGsi`,
  `MyTable/index/Gsi-index`
);

primaryIndex.grantReadWriteData(lambdaFn);
secondaryIndex.grantReadWriteData(lambdaFn);

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This is 🐛 Bug Report

[skinny85]

Hello @alonjupiter ,

thanks for opening the issue. Table.fromTableName() does not, in fact, create a new Table, but allows you to refer to an already existing one. Because of that, you have to specify all details of the Table yourself. If the Table has indexes, you need to use Table.fromTableAttributes method, and provide the indexes yourself.

Thanks, Adam

[alonjupiter]

Great stuff, thank you @skinny85!