Running Haskell AWS Lambda Functions

This repository contains code and directions to run Haskell executables over AWS Lambda "serverless" infrastructure. This experiment was triggered by reading description of apex provide a wrapper to run Go code.

Getting started

• Ensure access to AWS Lambda service:

  • use aws configure to define credentials and region to deploy to
  • create or use role for executing code on AWS Lambda

• Build docker container for building Haskell code that is supposed to be runnable on Amazon's Linux AMI

  cd ghc-centos
  docker build -t haskell-centos .
  cd ..
  

• Build haskell code:

  docker run -ti -v $(pwd):/build -w /build --name=haskell-build haskell-centos stack build --allow-different-user
  ...
  CONTAINER_ID=$(docker ps -a | grep haskell-centos | head -1 | cut -d ' ' -f 1)
  docker run --volumes-from=$CONTAINER_ID busybox dd if=/build/.stack-work/install/x86_64-linux/ghc-7.10.3/7.10.3/bin/main > main
  

• Build zip file containing Javascript wrapper and main app

  zip lambda.zip run.js main
  

• Create function on Lambda:

  $ aws lambda create-function --function-name hello-test --runtime nodejs4.3 --zip-file fileb://./aws-lambda.zip  --handler run.handle --role arn:aws:iam::259394719635:role/lambda
  {
      "CodeSha256": "QYKOebaDN/fqEzb1nmaV3ByNDZK3JvD0kWX6YQnPpjE=", 
      "FunctionName": "hello-test", 
      "CodeSize": 265356, 
      "MemorySize": 128, 
      "FunctionArn": "arn:aws:lambda:eu-west-1:259394719635:function:hello-test", 
      "Version": "$LATEST", 
      "Role": "arn:aws:iam::259394719635:role/lambda", 
      "Timeout": 20, 
      "LastModified": "2016-05-23T10:32:38.126+0000", 
      "Handler": "run.handle", 
      "Runtime": "nodejs4.3", 
      "Description": ""
  }
  

• Run function on Lambda:

  $ aws lamdba invoke-function --function-name hello-test
  {
      "StatusCode": 200
  }
  $ cat test
  "child process exited with code 0"
  

The provided main.hs simply output its input to its output. There should be an execution trace in the logs hosted on CloudWatch:

Manifest

• ghc-centos: Docker container for building Haskell binaries compatible with Amazon's Linux AMI. Does not seem to be a good idea in general as there are quite a few differences between CentOS and Linux AMI.
• run.js: Javascript wrapper to run binary in a child process
• test.js: Javascript test wrapper, invoke the handler simulating what AWS Lambda does
• stack.yaml, main.cabal, main.hs: Basic structure for building Haskell code

References

• Running executables in AWS Lambda
• Child processes in node
• AWS Lambda documentation