CategoriesServerless

Handling Change with AWS Healthlake

One of the features that I am currently missing with AWS Healthlake is a proper “event-ing” framework. With DynamoDB you’ve got streams. With RDS you can use DMS. But with Healthlake there is no native change data capture mechanism.

Being that I’m only working on event driven architectures these days, I needed a way to be able to handle change. What I’m going to show you below is not “sanctioned” but it is 100% AWS native and continues with the Serverless theme. With that said, here’s the Github Repository if you just want to jump ahead. The CDK code will deploy a Healthlake instance @ $.27 / hr so please run cdk destroy npx ts-node bin/app.ts` when you are done

CategoriesServerless

Mapping AWS State Machine output to API Gateway response with VTL

This is a continuation of a previous article I wrote regarding zero code workflows creating Cognito users with Step Functions. Part of using State Machines with API Gateway is the dealing with the response and potentially VTL mapping

Goals of this article are to document some of the tips and things that I picked up along the way.

CategoriesServerless

Creating an AWS Cognito User with an Auto-Incrementing ID using AWS Step Functions

So there are a couple of interesting topics in here.

  1. I’ve been really leaning into code-less workflows with AWS Step Functions and this State Machine has nothing but native SDK integrations which include
    • DynamoDB (Put, Delete, Get)
    • Cognito/User Pools (AdminCreateUser)
  2. I’ve run into some legacy code that requires a Username to be a bigint and I don’t want to use an RDBMS so I’m using DynamoDB to generate one for me while also being “race condition” proof

As always, if you want to jump straight to the code, here is the Github repository

CategoriesServerless

API Gateway Base Path Mapping

AWS API Gateway is fantastic for sitting in front of AWS resources like load balancers and lambda functions and it’s also really great for setting nice domain boundaries around you application code. Let’s enhance the API Gateway experience a little more by levering Base Path Mapping

For instance, if you have boundary A with a set of REST operations and a boundary B with another set of REST operations you now end up with 2 API Gateways with their own FQDN to access those resources. But what if you want to have those separate, but also roll them up under a common domain name? This is where using API Gateway Custom Domains and Base Path mapping while turning off the default endpoints is so helpful. Article below is going to be pretty concise but also very specific to this problem and show how to use API Gateway Base Path Mapping with CDK

If you want to jump to the code, here is the Github repos

CategoriesData

Querying AWS Healthlake from Go

When working with Healthcare data when of the things that’s often mentioned or discussed is “Is your data interoperable?” As a developer and an architect, that’s a really loaded word to me because if I can expose my data over files, APIs or some consistent channel like TCP, then by definition my system is interoperable. Per my Mac dictionary “interoperable” is an adjective defined like this :: (of computer systems or software) able to exchange and make use of information ::

However where things get a little more nuanced is when the definition includes some common healthcare specific formats and more specifically HL7’s FHIR. So when you have this problem, there are certain tools that you need to use. There are several opensource solutions that you could select but when you are an AWS’ customer, you start with AWS first. And they just so happy to have a set of capabilities wrapped around a product called Healthlake.