Last night I took Neuman Vong’s and Mark Wotton’s Haskell Buildpack for Heroku and got it working!

I’ve been able to deploy a simple Warp example and a in-development Yesod application. The steps are quite easy:

yesod init
cd yesod-buildpack-demo
mv deploy/Procfile .
git add -A
git commit -m "Initial commit"
heroku apps:create yesod-buildpack-demo --stack cedar --buildpack https://github.com/pufuwozu/heroku-buildpack-haskell.git
git push heroku master

The push will take quite a while for the first time, while it downloads packages. Packages are cached for the next push.

After it’s finished, the default Yesod application on Heroku:

No compilation locally! How awesome is that!?

Turns out this could have worked 5 months ago if it wasn’t for this bug:

$BUILD_DIR = $1

Notice the typo? An extra $. Heroku doesn’t report errors from the bin/release script in a Buildpack so Mark had no idea what was going wrong. I only found out by running the Buildpack locally with Mason.

Anyway, give the Buildpack a try and let me know what you think:

https://github.com/pufuwozu/heroku-buildpack-haskell