Step Functions <> Dynamodb integrations with dynamodb-toolbox features

A set of constructs to leverage dynamodb-toolbox features in a Step Functions <> Dynamodb direct integration.

Why ?

AWS direct integrations are great for shipping less custom code, thus less bugs 🐞 in your CDK applications. They enable communication with Dynamodb inside a state machine, rather than using a lambda as a service integration task and use your favorite tool such as dynamodb-toolbox to communicate with Dynamodb for simple requests like GetItem, PutItem, UpdateItem or Query.

However, functionless is not always an option and you may already be relying on dynamodb-toolbox in some of your lambdas. In this case, implementing a Step Functions <> Dynamodb direct integration turns out to be painful because you would have to implement dynamodb-toolbox features yourself (e.g. generate created / modified / entity properties, or handle alias and maps).

How ?

This library aims at getting the best developer experience :computer: while benefiting from dynamodb-toolbox features in Step Functions <> Dynamodb direct integrations. To query entity items inside a state machine, define your task with the Query construct at build time, and pass the partition key value at run time, just like you would do in a lambda with dynamodb-toolbox.

import { StateMachine } from "aws-cdk-lib/aws-stepfunctions";
import { DynamodbToolboxQuery } from "sfn-dynamodb-toolbox-integrations";

// Define your query state
const queryTask = new DynamodbToolboxQuery(this, "QueryTask", {
  entity: DynamodbToolboxEntityToQuery,
  tableArn: "arn:aws:dynamodb:us-east-2:123456789012:table/myDynamoDBTable",
  // Attributes to retrieve should be entity aliases
  options: { attributes: ["id", "created"] },
});

// And use it in your step function
const stateMachine = new StateMachine(this, "QueryStateMachine", {
  definition: queryTask,
});

NB: This library is in alpha for its current limitations, however it's already being used in production in some projects. The main limitation being: :warning: dynamodb-entities must be flat (i.e. no object or array properties).

We have released the Query construct while PutItem, UpdateItem and GetItem constructs are under active development.

Available DynamoDB-toolbox entity features

Entity definition

These entity properties are currently handled:

| DDB-toolbox entity options | GetItem | UpdateItem | PutItem | Query | | ----------------------------- | ---------- | ---------- | ---------- | --------------------------------------- | | attributes | :computer: | :computer: | :computer: | :warning: see below | | autoExecute | :computer: | :computer: | :computer: | :x: true (default) | | autoParse | :computer: | :computer: | :computer: | :x: true (default) | | created | :computer: | :computer: | :computer: | :white_check_mark: | | createdAlias | :computer: | :computer: | :computer: | :white_check_mark: | | modified | :computer: | :computer: | :computer: | :white_check_mark: | | modifiedAlias | :computer: | :computer: | :computer: | :white_check_mark: | | name | :computer: | :computer: | :computer: | :white_check_mark: | | table | :computer: | :computer: | :computer: | :white_check_mark: | | timestamps | :computer: | :computer: | :computer: | :white_check_mark: | | typeAlias | :computer: | :computer: | :computer: | :white_check_mark: | | typeHidden | :computer: | :computer: | :computer: | :x: false (default) |

:computer:: under development

Entity attributes

These entity attribute properties are currently handled:

| DDB-toolbox attribute feature | GetItem | UpdateItem | PutItem | Query | | ----------------------------- | ---------- | ---------- | ---------- | --------------------------------------- | | alias | :computer: | :computer: | :computer: | :white_check_mark: | | coerce | :computer: | :computer: | :computer: | :x: (default) | | default | :computer: | :computer: | :computer: | :white_check_mark: | | delimiter | :computer: | :computer: | :computer: | :white_check_mark: | | dependsOn | :computer: | :computer: | :computer: | :white_check_mark: | | format | :computer: | :computer: | :computer: | :x: | | hidden | :computer: | :computer: | :computer: | :x: false (default) | | map | :computer: | :computer: | :computer: | :white_check_mark: | | onUpdate | :computer: | :computer: | :computer: | :white_check_mark: | | prefix | :computer: | :computer: | :computer: | :x: | | suffix | :computer: | :computer: | :computer: | :x: | | partitionKey | :computer: | :computer: | :computer: | :white_check_mark: | | sortKey | :computer: | :computer: | :computer: | :white_check_mark: | | required | :computer: | :computer: | :computer: | :white_check_mark: | | save | :computer: | :computer: | :computer: | :x: true (default) | | setType | :computer: | :computer: | :computer: | :x: | | transform | :computer: | :computer: | :computer: | :x: | | type | :computer: | :computer: | :computer: | :warning: string, number, boolean |

:computer:: under development