This Haskell library turns any wai webapp (spock, servant, etc) into a handler for AWS Lambda and API Gateway requests.

{-# LANGUAGE OverloadedStrings #-} import Network.Wai import Network.HTTP.Types import Network.Wai.Handler.Lambda (run) app :: Application app _ respond = do putStrLn "I've done some IO here" respond $ responseLBS status200 [("Content-Type", "text/plain")] "Hello, Web!" main :: IO () main = run app

This doesn't require any particular Lambda environment. By following the instructions in the build section the resulting zip file uploaded to AWS Lambda is typically smaller than 1MB. For basic webapps the request handling duration (as reported by AWS) is between 1 and 5 milliseconds.

• Install with either Cabal, stack or Nix.
• Build for AWS with Nix and fully static executables.
• Deploy to AWS with Nix and Terraform.

Installing with Cabal:

$ cabal install wai-lambda

If you use stack and wai-lambda is not included in your snapshot, add it to the extra-deps:

extra-deps: - wai-lambda-0.1.0.0

or from GitHub:

packages: - ... - location: git: https://github.com/deckgo/wai-lambda.git commit: <some commit> extra-dep: true

You do not have to do anything if you use cabal2nix and a Nix commit that includes wai-lambda in its Hackage dependencies. If you want to use a specific commit of wai-lambda we recommend using niv:

$ niv add deckgo/wai-lambda

Then add an override to your Nix packages:

rec { sources = import ./nix/sources.nix; # from niv pkgs = import sources.nixpkgs {}; myHaskellPackages = pkgs.haskellPackages.override { overrides = self: super: { "wai-lambda" = super.callCabal2nix "wai-lambda" sources.wai-lambda; }; }; }

See also the build section for producing AWS Lambda packages with nix.

TODO

For inspiration on how to build fully static executables with Nix, see DeckDeckGo

TODO

For inspiration on how to deploy with Terraform and Nix, see DeckDeckGo

MIT © David Dal Busco and Nicolas Mattia