# Test and deploy to Heroku a Scala application

This example demonstrates the integration of Gitlab CI with Scala
applications using SBT. Checkout the example
[project](https://gitlab.com/gitlab-examples/scala-sbt) and
[build status](https://gitlab.com/gitlab-examples/scala-sbt/builds).

## Add `.gitlab-ci.yml` file to project

The following `.gitlab-ci.yml` should be added in the root of your
repository to trigger CI:

``` yaml
image: java:8

stages:
  - test
  - deploy

before_script:
  - apt-get update -y
  - apt-get install apt-transport-https -y
  ## Install SBT
  - echo "deb http://dl.bintray.com/sbt/debian /" | tee -a /etc/apt/sources.list.d/sbt.list
  - apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 642AC823
  - apt-get update -y
  - apt-get install sbt -y
  - sbt sbt-version

test:
  stage: test
  script:
    - sbt clean coverage test coverageReport

deploy:
  stage: deploy
  script:
    - apt-get update -yq
    - apt-get install rubygems ruby-dev -y
    - gem install dpl
    - dpl --provider=heroku --app=gitlab-play-sample-app --api-key=$HEROKU_API_KEY
```

The `before_script` installs [SBT](http://www.scala-sbt.org/) and
displays the version that is being used. The `test` stage executes SBT
to compile and test the project.
[scoverage](https://github.com/scoverage/sbt-scoverage) is used as an SBT
plugin to measure test coverage.
The `deploy` stage automatically deploys the project to Heroku using dpl.

You can use other versions of Scala and SBT by defining them in
`build.sbt`.

## Display test coverage in build

Add the `Coverage was \[\d+.\d+\%\]` regular expression in the
**Settings ➔ Edit Project ➔ Test coverage parsing** project setting to
retrieve the [test coverage] rate from the build trace and have it
displayed with your builds.

**Builds** must be enabled for this option to appear.

## Heroku application

A Heroku application is required. You can create one through the
[Dashboard](https://dashboard.heroku.com/). Substitute `gitlab-play-sample-app`
in the `.gitlab-ci.yml` file with your application's name.

## Heroku API key

You can look up your Heroku API key in your
[account](https://dashboard.heroku.com/account). Add a secure [variable] with
this value in **Project ➔ Variables** with key `HEROKU_API_KEY`.

[variable]: ../variables/README.md#user-defined-variables-secure-variables
[test coverage]: ../../user/project/pipelines/settings.md#test-coverage-report-badge
