deno-lambda VS aws-xray-sdk-node

Using Deno with AWS Lambda functions requires a custom runtime. You can build your own runtime or use one that already exists. If you’re concerned about security, I suggest maintaining a copy of an existing runtime and carefully inspecting updates or creating your own runtime. For this proof of concept, I deployed the Serverless Application Repository (SAR) app for Deno into my AWS account. I used the included Lambda layer and the provided.al2 Lambda runtime to create my Deno Lambda function. I created a file called index.ts with some basic JavaScript code that makes requests to two different websites and returns the HTTP status code of the response or a caught error. I then updated the function’s configuration to reference the exported handler function.

I'm doing a simple PoC / testing with Deno using https://github.com/hayd/deno-lambda and specifically the CDK instructions.

As I had mentioned, it requires using a Lambda Layer. See: https://github.com/hayd/deno-lambda/blob/2d90756a0f18b57f16e...

Using your own image (i.e. without using the base AWS image with the layer) you'd get even worse cold start times.

Decorators and TypeScript aren't supported out of the box in Lambda (without using deno) so we'll also need a transpilation step if we go this route. Fortunately this is a mostly solved problem for AWS CDK, AWS SAM and Serverless Framework users. If you want or need to roll your own, esbuild is a great place to start and seems to be the bundler of choice for this purpose.

In addition to the stuff posted here, there's the deno-lambda project for deploying to AWS Lambda

Cloud hosting support. Deno runs fine in a container, but lambda/cloud function support is difficult on most providers. deno-lambda exists but it only applies to AWS and can't be used with all CICD tools. Deno Deploy also exists but it's pretty new.

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