Example binary for wai-handler-hal

This package shows how to run a Servant API on AWS Lambda. Servant returns a WAI Application, which we wrap with wai-handler-hal and run with hal's 'mRuntime. This allows us to deploy the binary to AWS Lambda, and use it as a Lambda Proxy Integration of an AWS API Gateway REST API (only).

A second executable runs the same WAI Application on the warp web server. This is great for local testing.

Two endpoints are provided:

• GET https://abcde12345.execute-api.us-east-1.amazonaws.com/prod/hoot --- returns { "message": "hoot" }
• GET https://abcde12345.execute-api.us-east-1.amazonaws.com/prod/greet?person=Roy --- returns { "message": "Hello, Roy!" }

Building

In the wai-handler-hal-cdk/runtime directory, run nix build .#packages.x86_64-linux and wait a while. Nix will eventually create a result symlink containing the compressed bootstrap executable. From there, npx cdk deploy should deploy the example to AWS.

Hacking

There is a development shell provided. Users on x86_64-linux can run nix develop, and then run npm install from within the wai-handler-hal-cdk subdirectory.

Other Targets

Some people might prefer to deploy OCI Container Images to Elastic Container Registry. There are additional flake outputs showing how to package Lambda binaries into container images:

• packages.x86_64-linux.container is a standard container image built atop Amazon's base image.
• packages.x86_64-linux.tiny-continer is a minimal container image consisting of busybox, Amazon's AWS Lambda Runtime Interface Emulator, and the bootstrap binary.

Maintaining this Repo

We don't provide haskell-ci in the development shell, in case people copying the flake don't want it. To regenerate the GitHub Actions workflow:

nix run nixpkgs#haskell-ci regenerate