Heroku Haskell Stack Docker Image

An image for deploying Haskell/Stack applications to Heroku.

Usage

Create your own Dockerfile inheriting from this image:

FROM thoughtbot/heroku-haskell-stack

Create a stack-bootstrap file containing large dependencies for your application. For example:

alex classy-prelude-yesod happy yesod-bin yesod

These dependencies will be installed in their own Docker layer, so changing your cabal file will not cause them to be reinstalled every time.

Build your image:

docker build .

Here's a sample bin/deploy script you can use in your Heroku project, assuming you already have the heroku-docker Heroku plugin installed:

#!/bin/sh

set -e

if [ $# -ne 1 ]; then
  echo "Usage: ./bin/deploy (staging|production)"
  exit 1
fi

if [ $(uname) = "Darwin" ]; then
  eval "$(docker-machine env default)"
fi

heroku docker:release --remote "$1"
heroku open --remote "$1"

Running a script before building

Many applications need to do something before running the actual Stack build, such as compiling CSS. You can put commands in bin/pre-build and this Dockerfile will run them before building the application.