Gitlab CI - deploy to Heroku and run migrations - ruby-on-rails

Question

I have a Rails App hosted on gitlab.com, and I am configuring it to deploy to heroku following this guide: http://docs.gitlab.com/ce/ci/examples/test-and-deploy-ruby-application-to-heroku.html. It works fine.
My question is, how can I run migrations every time I deploy to heroku? When deploying via CLI I would usually do:
git push heroku master && heroku run rake db:migrate
but using gitlab-ci.yml I have no clue on how to do this...

Answer 1

If you want to be able to use the full power of the Heroku CLI in your GitLab CI process (including having the build fail if a migration fails for whichever reason), you can also try this approach which will install the Heroku CLI and deliver status codes of your Heroku commands back to GitLab, as well as, of course, the command line output. Using heroku run without credentials on the commandline require the HEROKU_API_KEY environment variable to be set to a key which has access to the app in question.
before_script:
- echo "deb http://toolbelt.heroku.com/ubuntu ./" > /etc/apt/sources.list.d/heroku.list
- wget -O- https://toolbelt.heroku.com/apt/release.key | apt-key add -
- apt-get update
- apt-get install -y heroku-toolbelt
- gem install dpl
stages:
- deploy
test_on_heroku:
type: deploy
script:
- dpl --provider=heroku --app=my_heroku_app --api-key=$HEROKU_API_KEY
- heroku run <your command here> --exit-code --app my_heroku_app
I actually run my tests on an Heroku instance to be sure, the environment is exactly the same. This is where this comes in real handy.

Answer 2

The information in this answer may be out of date. Please see both answers below, and remember to upvote the answers that are up to date to help future visitors.
here is a sample .yml I have that runs my tests then pushed to Heroku stage (for master branch pushes) or production (for tags pushes)
image: "ruby:2.3"
test:
script:
- apt-get update -qy
- apt-get install -y nodejs
- gem install bundler
- bundle install -j $(nproc) --without production
- bundle exec rails db:create RAILS_ENV=test
- bundle exec rails db:migrate RAILS_ENV=test
- bundle exec rails RAILS_ENV=test
staging:
type: deploy
environment: staging
script:
- gem install dpl
- dpl --provider=heroku --app=$HEROKU_STAGING_APP_NAME --api-key=$HEROKU_API_KEY
- "curl -n -X POST https://api.heroku.com/apps/$HEROKU_STAGING_APP_NAME/ps -H \"Accept: application/json\" -H \"Authorization: Bearer ${HEROKU_API_KEY}\" -d \"command=bundle exec rails db:migrate\""
only:
- master
production:
type: deploy
environment: production
script:
- gem install dpl
- dpl --provider=heroku --app=$HEROKU_PRODUCTION_APP_NAME --api-key=$HEROKU_API_KEY
- "curl -n -X POST https://api.heroku.com/apps/$HEROKU_PRODUCTION_APP_NAME/ps -H \"Accept: application/json\" -H \"Authorization: Bearer ${HEROKU_API_KEY}\" -d \"command=bundle exec rails db:migrate\""
only:
- tags

Answer 3

To update #huesforalice's answer, this would also work for the new Heroku CLI, which replaced Heroku Toolbelt in November 2016:
before_script:
- apt-get update
- apt-get install apt-transport-https
- echo "deb https://cli-assets.heroku.com/branches/stable/apt ./" > /etc/apt/sources.list.d/heroku.list
- wget -O- https://cli-assets.heroku.com/apt/release.key | apt-key add -
- apt-get update
- apt-get install -y heroku
- gem install dpl
staging:
type: deploy
variables:
HEROKU_API_KEY: $HEROKU_STAGING_API_KEY
script:
- dpl --provider=heroku --app=$HEROKU_STAGING_APP --api-key=$HEROKU_STAGING_API_KEY
- heroku run rails db:migrate --exit-code --app $HEROKU_STAGING_APP
only:
- master
production:
type: deploy
variables:
HEROKU_API_KEY: $HEROKU_PRODUCTION_API_KEY
script:
- dpl --provider=heroku --app=$HEROKU_PRODUCTION_APP --api-key=$HEROKU_PRODUCTION_API_KEY
- heroku run rails db:migrate --exit-code --app $HEROKU_PRODUCTION_APP
only:
- tags

Answer 4

To further improve #huesforalice and #Jimmy Bosse 's answers - If you want to
avoid putting Heroku CLI installation in the global before_script but only use it in the deployment stages
at the same time, avoid copying and pasting the installation snippet into different stages
You can do something like this using YAML anchors to DRY up
before_script:
# the global before_script
- gem install bundler --no-document
- bundle check || bundle install --jobs $(nproc)
.deployment_before_script: &deployment_before_script
before_script:
- echo "deb http://toolbelt.heroku.com/ubuntu ./" > /etc/apt/sources.list.d/heroku.list
- wget -O- https://toolbelt.heroku.com/apt/release.key | apt-key add -
- apt-get update
- apt-get install -y heroku-toolbelt
- gem install dpl
# other stages...
staging:
stage: deploy
<<: *deployment_before_script
script:
- dpl --provider=heroku --app=$HEROKU_APP_STAGING --api-key=$HEROKU_API_KEY_STAGING
- heroku run bundle exec rails db:migrate --exit-code --app $HEROKU_APP_STAGING
only:
- master
production:
stage: deploy
<<: *deployment_before_script
script:
- dpl --provider=heroku --app=$HEROKU_APP_PRODUCTION --api-key=$HEROKU_API_KEY_STAGING
- heroku run bundle exec rails db:migrate --exit-code --app $HEROKU_APP_PRODUCTION
when: manual
only:
- tags