sfn-dynamodb-toolbox-integrations

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 💻 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: ⚠️ 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	💻	💻	💻	⚠️ see below
autoExecute	💻	💻	💻	❌ true (default)
autoParse	💻	💻	💻	❌ true (default)
created	💻	💻	💻	✅
createdAlias	💻	💻	💻	✅
modified	💻	💻	💻	✅
modifiedAlias	💻	💻	💻	✅
name	💻	💻	💻	✅
table	💻	💻	💻	✅
timestamps	💻	💻	💻	✅
typeAlias	💻	💻	💻	✅
typeHidden	💻	💻	💻	❌ false (default)

💻: under development

Entity attributes

These entity attribute properties are currently handled:

DDB-toolbox attribute feature	GetItem	UpdateItem	PutItem	Query
alias	💻	💻	💻	✅
coerce	💻	💻	💻	❌ (default)
default	💻	💻	💻	✅
delimiter	💻	💻	💻	✅
dependsOn	💻	💻	💻	✅
format	💻	💻	💻	❌
hidden	💻	💻	💻	❌ false (default)
map	💻	💻	💻	✅
onUpdate	💻	💻	💻	✅
prefix	💻	💻	💻	❌
suffix	💻	💻	💻	❌
partitionKey	💻	💻	💻	✅
sortKey	💻	💻	💻	✅
required	💻	💻	💻	✅
save	💻	💻	💻	❌ true (default)
setType	💻	💻	💻	❌
transform	💻	💻	💻	❌
type	💻	💻	💻	⚠️ string, number, boolean

💻: under development