Using Dpl as a deployment tool

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Dpl (pronounced like the letters D-P-L) is a deploy tool made for continuous deployment that's developed and used by Travis CI, but can also be used with GitLab CI/CD.

Dpl can be used to deploy to any of the supported providers.

Prerequisite

To use Dpl you need at least Ruby 1.9.3 with ability to install gems.

Basic usage

Dpl can be installed on any machine with:

gem install dpl

This allows you to test all commands from your local terminal, rather than having to test it on a CI server.

If you don't have Ruby installed you can do it on Debian-compatible Linux with:

apt-get update
apt-get install ruby-dev

The Dpl provides support for vast number of services, including: Heroku, Cloud Foundry, AWS/S3, and more. To use it, define provider and any additional parameters required by the provider.

For example if you want to use it to deploy your application to Heroku, you need to specify heroku as provider, specify api_key and app. All possible parameters can be found in the Heroku API section.

staging:
  stage: deploy
  script:
    - gem install dpl
    - dpl heroku api --app=my-app-staging --api_key=$HEROKU_STAGING_API_KEY
  environment: staging

In the above example we use Dpl to deploy my-app-staging to Heroku server with API key stored in HEROKU_STAGING_API_KEY secure variable.

To use different provider take a look at long list of Supported Providers.

Using Dpl with Docker

In most cases, you configured GitLab Runner to use your server's shell commands. This means that all commands are run in the context of local user (for example gitlab_runner or gitlab_ci_multi_runner). It also means that most probably in your Docker container you don't have the Ruby runtime installed. You must install it:

staging:
  stage: deploy
  script:
    - apt-get update -yq
    - apt-get install -y ruby-dev
    - gem install dpl
    - dpl heroku api --app=my-app-staging --api_key=$HEROKU_STAGING_API_KEY
  rules:
    - if: $CI_COMMIT_BRANCH == "main"
  environment: staging

The first line apt-get update -yq updates the list of available packages, where second apt-get install -y ruby-dev installs the Ruby runtime on system. The above example is valid for all Debian-compatible systems.

Usage in staging and production

It's pretty common in the development workflow to have staging (development) and production environments

Let's consider the following example: we would like to deploy the main branch to staging and all tags to the production environment. The final .gitlab-ci.yml for that setup would look like this:

staging:
  stage: deploy
  script:
    - gem install dpl
    - dpl heroku api --app=my-app-staging --api_key=$HEROKU_STAGING_API_KEY
  rules:
    - if: $CI_COMMIT_BRANCH == "main"
  environment: staging

production:
  stage: deploy
  script:
    - gem install dpl
    - dpl heroku api --app=my-app-production --api_key=$HEROKU_PRODUCTION_API_KEY
  rules:
    - if: $CI_COMMIT_TAG
  environment: production

We created two deploy jobs that are executed on different events:

staging: Executed for all commits pushed to the main branch
production: Executed for all pushed tags

We also use two secure variables:

HEROKU_STAGING_API_KEY: Heroku API key used to deploy staging app
HEROKU_PRODUCTION_API_KEY: Heroku API key used to deploy production app

Storing API keys

To store API keys as secure variables:

On the left sidebar, select Search or go to and find your project.
Select Settings > CI/CD.
Expand Variables.

The variables defined in the project settings are sent along with the build script to the runner. The secure variables are stored out of the repository. Never store secrets in your project's .gitlab-ci.yml file. It is also important that the secret's value is hidden in the job log.

You access added variable by prefixing it's name with $ (on non-Windows runners) or % (for Windows Batch runners):

$VARIABLE: Use for non-Windows runners
%VARIABLE%: Use for Windows Batch runners