middy VS aws-xray-sdk-node

In many cases, you will have to write the same authorization code in multiple functions. For example, you might want to check that the user is in the requested organization. You can share this code in a middleware. If you are using AWS Lambda, you can rely on middy.

Adding the is-test flag to our object metadata gave us our way of passing some kind of test context into our workload. The next step was to make the Lambda Function capable of discovering the context and then using that to control how it behaves under test. For this we used Middy.

I also decided to use the middy library to add CORS management to our lambda function. This will allow us to call our lambda function from our frontend, without having to worry about CORS.

Is there any equivalent to Node based https://middy.js.org/ for Golang?

And if your requirements were to change at a later date, it’s straightforward to swap out SSM Parameter Store with Secrets Manager there and then. Especially if you’re accessing the relevant service through a middleware layer such as Middy for javascript Lambda functions.

This function uses the Middy middleware engine to handle unhandled errors and add CORS headers in the response.

I mean I'm literally building an AWS lambda function that outputs HTML when it's called via API Gateway. So someone hits https://mydomain.com/mycoolpage, then the MyCoolPage AWS Lambda function is executed and outputs whatever.

If you're interested, I use https://middy.js.org/ as a middleware engine for my AWS lambda functions which I find helpful.

I use the open sourced serverless framework for doing deploys https://www.serverless.com/

middy for lambda-side middleware

That is it from the CDK side. Now let us create the handler and retrieve that secret. I like to use middy which describes itself as "stylish Node.js middleware engine for AWS Lambda". It offers some helpful middlewares like ssm which will help us retrieve and cache values from SSM Parameter Store. (Middy provides various other official middlewares including one for Secrets Manager.) I prefer a middleware for this because it keeps the code for retrieving the secret out of your handler which should deal with actual business logic.

You see in the node xrays sdk that each AWS service is customized with the captureAWSRequest function, which is responsible for the X-Ray calls.

Generally speaking, it is encouraged on serverless-heavy environments (assuming Lambdas, API Gateways, AppSync, DynamoDB and similar services were configured to use it). However, some crucial pieces are still missing, like a proper SQS integration. Bear that in mind.

So what do we get for that? The Tracer module wraps the AWS X-Ray SDK (as a transitive dependency). It doesn't really add any net new capabilities, but makes the SDK easier to work with. In my experience, that SDK is a bit of a bear so this may be well worth it. We can decorate class methods to introduce new trace segments in a single line of code. We can also use the imperative form to add new traces where we see fit. We can capture AWS clients, but that simply exposes the X-Ray SDK.

aws-xray-sdk-node: https://github.com/aws/aws-xray-sdk-node/issues/208