Integrations development guidelines

This page provides development guidelines for implementing GitLab integrations, which are part of our main Rails project.

Also see our direction page for an overview of our strategy around integrations.

This guide is a work in progress. You're welcome to ping @gitlab-org/manage/integrations if you need clarification or spot any outdated information.

Add a new integration

Define the integration

1. Add a new model in app/models/integrations extending from Integration.

   • For example, Integrations::FooBar in app/models/integrations/foo_bar.rb.
   • For certain types of integrations, you can also build on these base classes:
     • Integrations::BaseChatNotification
     • Integrations::BaseCi
     • Integrations::BaseIssueTracker
     • Integrations::BaseMonitoring
     • Integrations::BaseSlashCommands
     • Integrations::BaseThirdPartyWiki
   • For integrations that primarily trigger HTTP calls to external services, you can also use the Integrations::HasWebHook concern. This reuses the webhook functionality in GitLab through an associated ServiceHook model, and automatically records request logs which can be viewed in the integration settings.

2. Add the integration's underscored name ('foo_bar') to Integration::INTEGRATION_NAMES.

3. Add the integration as an association on Project:

   has_one :foo_bar_integration, class_name: 'Integrations::FooBar'

Define properties

Integrations can define arbitrary properties to store their configuration with the class method Integration.prop_accessor. The values are stored as an encrypted JSON hash in the integrations.encrypted_properties column.

For example:

module Integrations
  class FooBar < Integration
    prop_accessor :url
    prop_accessor :tags
  end
end

Integration.prop_accessor installs accessor methods on the class. Here we would have #url, #url= and #url_changed?, to manage the url field. Fields stored in Integration#properties should be accessed by these accessors directly on the model, just like other ActiveRecord attributes.

You should always access the properties through their getters, and not interact with the properties hash directly. You must not write to the properties hash, you must use the generated setter method instead. Direct writes to this hash are not persisted.

You should also define validations for all your properties.

Also refer to the section Customize the frontend form below to see how these properties are exposed in the frontend form for the integration.

There is an alternative approach using Integration.data_field, which you may see in other integrations. With data fields the values are stored in a separate table per integration. At the moment we don't recommend using this for new integrations.

Define trigger events

Integrations are triggered by calling their #execute method in response to events in GitLab, which gets passed a payload hash with details about the event.

The supported events have some overlap with webhook events, and receive the same payload. You can specify the events you're interested in by overriding the class method Integration.supported_events in your model.

The following events are supported for integrations:

Event examples

This example defines an integration that responds to commit and merge_request events:

module Integrations
  class FooBar < Integration
    def self.supported_events
      %w[commit merge_request]
    end
  end
end

An integration can also not respond to events, and implement custom functionality some other way:

module Integrations
  class FooBar < Integration
    def self.supported_events
      []
    end
  end
end

Define configuration test

Optionally, you can define a configuration test of an integration's settings. The test is executed from the integration form's Test button, and results are returned to the user.

A good configuration test:

• Does not change data on the service. For example, it should not trigger a CI build. Sending a message is okay.
• Is meaningful and as thorough as possible.

If it's not possible to follow the above guidelines, consider not adding a configuration test.

To add a configuration test, define a #test method for the integration model.

The method receives data, which is a test push event payload. It should return a hash, containing the keys:

• success (required): a boolean to indicate if the configuration test has passed.
• result (optional): a message returned to the user if the configuration test has failed.

For example:

module Integrations
  class FooBar < Integration
    def test(data)
      success = test_api_key(data)

      { success: success, result: 'API key is invalid' }
    end
  end
end

Customize the frontend form

The frontend form is generated dynamically based on metadata defined in the model.

By default, the integration form provides:

• A checkbox to enable or disable the integration.
• Checkboxes for each of the trigger events returned from Integration#configurable_events.

You can also add help text at the top of the form by either overriding Integration#help, or providing a template in app/views/shared/integrations/$INTEGRATION_NAME/_help.html.haml.

To add your custom properties to the form, you can define the metadata for them in Integration#fields.

This method should return an array of hashes for each field, where the keys can be:

Additional keys for type: 'checkbox'

Additional keys for type: 'select'

Additional keys for type: 'password'

Frontend form examples

This example defines a required url field, and optional username and password fields:

module Integrations
  class FooBar < Integration
    prop_accessor :url, :username, :password

    def fields
      [
        {
          type: 'text',
          name: 'url',
          title: s_('FooBarIntegration|Server URL'),
          placeholder: 'https://example.com/',
          required: true
        },
        {
          type: 'text',
          name: 'username',
          title: s_('FooBarIntegration|Username'),
        },
        {
          type: 'password',
          name: 'password',
          title: s_('FoobarIntegration|Password'
          non_empty_password_title: s_('FooBarIntegration|Enter new password')
        }
      ]
    end
  end
end

Expose the integration in the REST API

To expose the integration in the REST API:

1. Add the integration's class (::Integrations::FooBar) to API::Helpers::IntegrationsHelpers.integration_classes.
2. Add all properties that should be exposed to API::Helpers::IntegrationsHelpers.integrations.
3. Update the reference documentation in doc/api/integrations.md, add a new section for your integration, and document all properties.

You can also refer to our REST API style guide.

Sensitive fields are not exposed over the API. Sensitive fields are those fields that contain any of the following in their name:

• key
• passphrase
• password
• secret
• token
• webhook

Availability of integrations

By default, integrations are available on the project, group, and instance level. Most integrations only act in a project context, but can be still configured from the group and instance levels.

For some integrations it can make sense to only make it available on the project level. To do that, the integration must be removed from Integration::INTEGRATION_NAMES and added to Integration::PROJECT_SPECIFIC_INTEGRATION_NAMES instead.

When developing a new integration, we also recommend you gate the availability behind a feature flag in Integration.available_integration_names.

Documentation

You can provide help text in the integration form, including links to off-site documentation, as described above in Customize the frontend form. Refer to our usability guidelines for help text.

For more detailed documentation, provide a page in doc/user/project/integrations, and link it from the Integrations overview.

You can also refer to our general documentation guidelines.

Testing

Testing should not be confused with defining configuration tests.

It is often sufficient to add tests for the integration model in spec/models/integrations, and a factory with example settings in spec/factories/integrations.rb.

Each integration is also tested as part of generalized tests. For example, there are feature specs that verify that the settings form is rendering correctly for all integrations.

If your integration implements any custom behavior, especially in the frontend, this should be covered by additional tests.

You can also refer to our general testing guidelines.

Internationalization

All UI strings should be prepared for translation by following our internationalization guidelines.

The strings should use the integration name as namespace, for example, s_('FooBarIntegration|My string').

Deprecate and remove an integration

To remove an integration, you must first deprecate the integration. For more information, see the feature deprecation guidelines.

Deprecate an integration

You must announce any deprecation no later than the third milestone preceding intended removal. To deprecate an integration:

• Add a deprecation entry.
• Mark the integration documentation as deprecated.
• Optional. To prevent any new project-level records from being created, add the integration to Project#disabled_integrations (see example merge request).

Remove an integration

To safely remove an integration, you must stage the removal across two milestones.

In the major milestone of intended removal (M.0), disable the integration and delete the records from the database:

• Remove the integration from Integration::INTEGRATION_NAMES.
• Delete the integration model's #execute and #test methods (if defined), but keep the model.
• Add a post-migration to delete the integration records from PostgreSQL (see example merge request).
• Add a removal entry.
• Mark the integration documentation as removed.
• Update the integration API documentation.

In the next minor release (M.1):

• Remove the integration's model and any remaining code.
• Close any issues, merge requests, and epics that have the integration's label (~Integration::<name>).
• Delete the integration's label (~Integration::<name>) from gitlab-org.

Ongoing migrations and refactorings

Developers should be aware that the Integrations team is in the process of unifying the way integration properties are defined.

Integration examples

You can refer to these issues for examples of adding new integrations:

• Datadog: Metrics collector, similar to the Prometheus integration.
• EWM/RTC: External issue tracker.
• Shimo: External wiki, similar to the Confluence and External Wiki integrations.
• Webex Teams: Chat notifications.
• ZenTao: External issue tracker with custom issue views, similar to the Jira integration.