This is an example for Nix deployment to Heroku using the heroku-buildpack-nix-proot buildpack. See that buildpack for more general instructions.

Dokku can be used for a local test environment. A .env file has been included to set the buildpack appropriately.

To start, create a secrets.sh file with your S3 credentials like this:

export NIX_S3_KEY=...
export NIX_S3_SECRET=...
export NIX_S3_BUCKET=...

I suggest you deploy locally on Dokku first to build a binary closure that will be uploaded to S3. Deploying to Heroku will then pick up the remote closure and run much faster.

Deployment

Dokku

Easiest to set up Dokku using Vagrant.

(Note: As of 2015-01-23, you should ignore the advice to set the port in ~/.ssh/config.)

You will need to change the mode of apparmor (installed by Docker) to allow proot to work.

Enter your Dokku folder and type:

vagrant ssh
# on vm
sudo apt-get install apparmor-utils
sudo aa-complain /etc/apparmor.d/docker

Then, in this repo:

source secrets.sh
APP_NAME=deploy_nix
ssh dokku@dokku.me config:set $APP_NAME \
                  NIX_S3_KEY=$NIX_S3_KEY \
                  NIX_S3_SECRET=$NIX_S3_SECRET \
                  NIX_S3_BUCKET=$NIX_S3_BUCKET \
                  NIX_BUILD_ON_PUSH=1
git remote add dokku dokku@dokku.me:$APP_NAME
git push dokku master

If you wish, you can omit NIX_BUILD_ON_PUSH above and instead manually run ssh dokku@dokku.me run $APP_NAME build.

Heroku

To deploy directly to Heroku:

source secrets.sh
heroku create -b http://github.com/chrisjr/heroku-buildpack-nix-proot
heroku config:set NIX_S3_KEY=$NIX_S3_KEY \
                  NIX_S3_SECRET=$NIX_S3_SECRET \
                  NIX_S3_BUCKET=$NIX_S3_BUCKET
git push heroku master
# wait for Nix install...

If you use the Dokku method above, a binary closure will already be saved that Heroku can pick up without needing to use up dyno hours building.

If not, you can build remotely as follows:

heroku run build
# for a larger app, you may need `heroku run -s PX build`

# final deploy
git commit --amend --no-edit
git push -f heroku master

If you wish to recompile when pushing changes directly to Heroku, you can set heroku config:set NIX_BUILD_ON_PUSH=1. (This might make more sense on dokku, since it will not run out of time.)