gitlab-org--gitlab-foss/doc/development/snowplow/implementation.md

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Implement Snowplow tracking

This page describes how to:

• Implement Snowplow frontend and backend tracking
• Test Snowplow events

Snowplow JavaScript frontend tracking

GitLab provides a Tracking interface that wraps the Snowplow JavaScript tracker to track custom events.

For the recommended frontend tracking implementation, see Usage recommendations.

Tracking implementations must have an action and a category. You can provide additional categories from the structured event taxonomy with an extra object that accepts key-value pairs.

Field	Type	Default value	Description
category	string	document.body.dataset.page	Page or subsection of a page in which events are captured.
action	string	generic	Action the user is taking. Clicks must be click and activations must be activate. For example, focusing a form field is activate_form_input, and clicking a button is click_button.
data	object	{}	Additional data such as label, property, value, context as described in Structured event taxonomy, and extra (key-value pairs object).

Usage recommendations

• Use data attributes on HTML elements that emit click, show.bs.dropdown, or hide.bs.dropdown events.
• Use the Vue mixin for tracking custom events, or if the supported events for data attributes are not propagating.
• Use the tracking class when tracking raw JavaScript files.

Implement data attribute tracking

To implement tracking for HAML or Vue templates, add a data-track attribute to the element.

The following example shows data-track-* attributes assigned to a button:

%button.btn{ data: { track: { action: "click_button", label: "template_preview", property: "my-template" } } }

<button class="btn"
  data-track-action="click_button"
  data-track-label="template_preview"
  data-track-property="my-template"
  data-track-extra='{ "template_variant": "primary" }'
/>

data-track attributes

Attribute	Required	Description
data-track-action	true	Action the user is taking. Clicks must be prepended with click and activations must be prepended with activate. For example, focusing a form field is activate_form_input and clicking a button is click_button. Replaces data-track-event, which was deprecated in GitLab 13.11.
data-track-label	false	The specific element or object to act on. This can be: the label of the element, for example, a tab labeled 'Create from template' for create_from_template; a unique identifier if no text is available, for example, groups_dropdown_close for closing the Groups dropdown in the top bar; or the name or title attribute of a record being created.
data-track-property	false	Any additional property of the element, or object being acted on.
data-track-value	false	Describes a numeric value or something directly related to the event. This could be the value of an input. For example, 10 when clicking internal visibility. If omitted, this is the element's value property or undefined. For checkboxes, the default value is the element's checked attribute or 0 when unchecked.
data-track-extra	false	A key-value pair object passed as a valid JSON string. This attribute is added to the extra property in our gitlab_standard schema.
data-track-context	false	The context as described in our Structured event taxonomy.

Event listeners

Event listeners bind at the document level to handle click events in elements with data attributes. This allows them to be handled when the DOM re-renders or changes. Document-level binding reduces the likelihood that click events stop propagating up the DOM tree.

If click events stop propagating, you must implement listeners and Vue component tracking or raw JavaScript tracking.

Helper methods

Use the following Ruby helper:

tracking_attrs(label, action, property) # { data: { track_label... } }

%button{ **tracking_attrs('main_navigation', 'click_button', 'navigation') }

If you use the GitLab helper method nav_link, you must wrap html_options under the html_options keyword argument. If you use the ActionView helper method link_to, you don't need to wrap html_options.

# Bad
= nav_link(controller: ['dashboard/groups', 'explore/groups'], data: { track_label: "explore_groups",
track_action: "click_button" })

# Good
= nav_link(controller: ['dashboard/groups', 'explore/groups'], html_options: { data: { track_label: 
"explore_groups", track_action: "click_button" } })

# Good (other helpers)
= link_to explore_groups_path, title: _("Explore"), data: { track_label: "explore_groups", track_action:
"click_button" }

Implement Vue component tracking

For custom event tracking, use a Vue mixin in components. Vue mixin exposes the Tracking.event static method and the track method. You can specify tracking options in data or computed. These options override any defaults and allow the values to be dynamic from props or based on state.

Several default options are passed when an event is tracked from the component:

• category: If you don't specify, by default document.body.dataset.page is used.
• label
• property
• value

To implement Vue component tracking:

1. Import the Tracking library and request a mixin:

   import Tracking from '~/tracking';
   const trackingMixin = Tracking.mixin;
   

2. Provide categories to track the event from the component. For example, to track all events in a component with a label, use the label category:

   import Tracking from '~/tracking';
   const trackingMixin = Tracking.mixin({ label: 'right_sidebar' });
   

3. In the component, declare the Vue mixin:

   export default {
     mixins: [trackingMixin],
     // ...[component implementation]...
     data() {
       return {
         expanded: false,
         tracking: {
           label: 'left_sidebar',
         },
       };
     },
   };
   

4. To receive event data as a tracking object or computed property:

   • Declare it in the data function. Use a tracking object when default event properties are dynamic or provided at runtime:

     export default {
       name: 'RightSidebar',
       mixins: [Tracking.mixin()],
       data() {
         return {
           tracking: {
             label: 'right_sidebar',
             // category: '',
             // property: '',
             // value: '',
             // experiment: '',
             // extra: {},
           },
         };
       },
     };
     

   • Declare it in the event data in the track function. This object merges with any previously provided options:

     this.track('click_button', {
       label: 'right_sidebar',
     });
     

5. Optional. Use the track method in a template:

   <template>
     <div>
       <button data-testid="toggle" @click="toggle">Toggle</button>
   
       <div v-if="expanded">
         <p>Hello world!</p>
         <button @click="track('click_action')">Track another event</button>
       </div>
     </div>
   </template>
   

The following example shows an implementation of Vue component tracking:

export default {
  name: 'RightSidebar',
  mixins: [Tracking.mixin({ label: 'right_sidebar' })],
  data() {
    return {
      expanded: false,
    };
  },
  methods: {
    toggle() {
      this.expanded = !this.expanded;
      // Additional data will be merged, like `value` below
      this.track('click_toggle', { value: Number(this.expanded) });
    }
  }
};

Testing example

import { mockTracking } from 'helpers/tracking_helper';
// mockTracking(category, documentOverride, spyMethod)

describe('RightSidebar.vue', () => {
  let trackingSpy;
  let wrapper;

  beforeEach(() => {
    trackingSpy = mockTracking(undefined, wrapper.element, jest.spyOn);
  });

  const findToggle = () => wrapper.find('[data-testid="toggle"]');

  it('tracks turning off toggle', () => {
    findToggle().trigger('click');

    expect(trackingSpy).toHaveBeenCalledWith(undefined, 'click_toggle', {
      label: 'right_sidebar',
      value: 0,
    });
  });
});

Implement raw JavaScript tracking

To call custom event tracking and instrumentation directly from the JavaScript file, call the Tracking.event static function.

The following example demonstrates tracking a click on a button by manually calling Tracking.event.

import Tracking from '~/tracking';

const button = document.getElementById('create_from_template_button');

button.addEventListener('click', () => {
  Tracking.event('dashboard:projects:index', 'click_button', {
    label: 'create_from_template',
    property: 'template_preview',
    extra: {
      templateVariant: 'primary',
      valid: 1,
    },
  });
});

Testing example

import Tracking from '~/tracking';

describe('MyTracking', () => {
  let wrapper;

  beforeEach(() => {
    jest.spyOn(Tracking, 'event');
  });

  const findButton = () => wrapper.find('[data-testid="create_from_template"]');

  it('tracks event', () => {
    findButton().trigger('click');

    expect(Tracking.event).toHaveBeenCalledWith(undefined, 'click_button', {
      label: 'create_from_template',
      property: 'template_preview',
      extra: {
        templateVariant: 'primary',
        valid: true,
      },
    });
  });
});

Form tracking

To enable Snowplow automatic form tracking:

1. Call Tracking.enableFormTracking when the DOM is ready.
2. Provide a config object that includes at least one of the following elements:
   • forms determines the forms to track. Identified by the CSS class name.
   • fields determines the fields inside the tracked forms to track. Identified by the field name.
3. Optional. Provide a list of contexts as the second argument. The gitlab_standard schema is excluded from these events.

Tracking.enableFormTracking({
  forms: { allow: ['sign-in-form', 'password-recovery-form'] },
  fields: { allow: ['terms_and_conditions', 'newsletter_agreement'] },
});

Testing example

import Tracking from '~/tracking';

describe('MyFormTracking', () => {
  let formTrackingSpy;

  beforeEach(() => {
    formTrackingSpy = jest
      .spyOn(Tracking, 'enableFormTracking')
      .mockImplementation(() => null);
  });

  it('initialized with the correct configuration', () => {
    expect(formTrackingSpy).toHaveBeenCalledWith({
      forms: { allow: ['sign-in-form', 'password-recovery-form'] },
      fields: { allow: ['terms_and_conditions', 'newsletter_agreement'] },
    });
  });
});

Implement Ruby backend tracking

Gitlab::Tracking is an interface that wraps the Snowplow Ruby Tracker for tracking custom events. Backend tracking provides:

• User behavior tracking
• Instrumentation to monitor and visualize performance over time in a section or aspect of code.

To add custom event tracking and instrumentation, call the GitLab::Tracking.event class method. For example:

class Projects::CreateService < BaseService
  def execute
    project = Project.create(params)

    Gitlab::Tracking.event('Projects::CreateService', 'create_project', label: project.errors.full_messages.to_sentence,
                           property: project.valid?.to_s, project: project, user: current_user, namespace: namespace)
  end
end

Use the following arguments:

Argument	Type	Default value	Description
category	String		Area or aspect of the application. For example, HealthCheckController or Lfs::FileTransformer.
action	String		The action being taken. For example, a controller action such as create, or an Active Record callback.
label	String	nil	The specific element or object to act on. This can be one of the following: the label of the element, for example, a tab labeled 'Create from template' for create_from_template; a unique identifier if no text is available, for example, groups_dropdown_close for closing the Groups dropdown in the top bar; or the name or title attribute of a record being created.
property	String	nil	Any additional property of the element, or object being acted on.
value	Numeric	nil	Describes a numeric value or something directly related to the event. This could be the value of an input. For example, 10 when clicking internal visibility.
context	Array[SelfDescribingJSON]	nil	An array of custom contexts to send with this event. Most events should not have any custom contexts.
project	Project	nil	The project associated with the event.
user	User	nil	The user associated with the event.
namespace	Namespace	nil	The namespace associated with the event.
extra	Hash	{}	Additional keyword arguments are collected into a hash and sent with the event.

Unit testing

To test backend Snowplow events, use the expect_snowplow_event helper. For more information, see testing best practices.

Performance

We use the AsyncEmitter when tracking events, which allows for instrumentation calls to be run in a background thread. This is still an active area of development.

Develop and test Snowplow

To develop and test a Snowplow event, there are several tools to test frontend and backend events:

Testing Tool	Frontend Tracking	Backend Tracking	Local Development Environment	Production Environment	Production Environment
Snowplow Analytics Debugger Chrome Extension	Yes	No	Yes	Yes	Yes
Snowplow Inspector Chrome Extension	Yes	No	Yes	Yes	Yes
Snowplow Micro	Yes	Yes	Yes	No	No

Test frontend events

Before you test frontend events in development, you must:

1. Enable Snowplow tracking in the Admin Area.
2. Turn off ad blockers that could prevent Snowplow JavaScript from loading in your environment.
3. Turn off "Do Not Track" (DNT) in your browser.

All URLs are pseudonymized. The entity identifier replaces personally identifiable information (PII). PII includes usernames, group, and project names.

Snowplow Analytics Debugger Chrome Extension

Snowplow Analytics Debugger is a browser extension for testing frontend events. It works in production, staging, and local development environments.

1. Install the Snowplow Analytics Debugger Chrome browser extension.
2. Open Chrome DevTools to the Snowplow Analytics Debugger tab.

Snowplow Inspector Chrome Extension

Snowplow Inspector Chrome Extension is a browser extension for testing frontend events. This works in production, staging, and local development environments.

1. Install Snowplow Inspector.
2. To open the extension, select the Snowplow Inspector icon beside the address bar.
3. Click around on a webpage with Snowplow to see JavaScript events firing in the inspector window.

Test backend events

Snowplow Micro

Snowplow Micro is a Docker-based solution for testing backend and frontend in a local development environment. Snowplow Micro records the same events as the full Snowplow pipeline. To query events, use the Snowplow Micro API.

To install and run Snowplow Micro, complete these steps to modify the GitLab Development Kit (GDK):

1. Ensure Docker is installed and running.

2. To install Snowplow Micro, clone the settings in this project.

3. Navigate to the directory with the cloned project, and start the appropriate Docker container:

   ./snowplow-micro.sh
   

4. Set the environment variable to tell the GDK to use Snowplow Micro in development. This overrides two application_settings options:

   • snowplow_enabled setting will instead return true from Gitlab::Tracking.enabled?
   • snowplow_collector_hostname setting will instead always return localhost:9090 (or whatever is set for SNOWPLOW_MICRO_URI) from Gitlab::Tracking.collector_hostname.

   export SNOWPLOW_MICRO_ENABLE=1
   

   Optionally, you can set the URI for you Snowplow Micro instance as well (the default value is http://localhost:9090):

   export SNOWPLOW_MICRO_URI=https://127.0.0.1:8080
   

5. Restart GDK:

   gdk restart
   

6. Send a test Snowplow event from the Rails console:

   Gitlab::Tracking.event('category', 'action')
   

7. Navigate to localhost:9090/micro/good to see the event.

Useful links

• Snowplow Micro repository
• Installation guide recording

Troubleshoot

To control content security policy warnings when using an external host, modify config/gitlab.yml to allow or disallow them. To allow them, add the relevant host for connect_src. For example, for https://snowplow.trx.gitlab.net:

development:
  <<: *base
  gitlab:
    content_security_policy:
      enabled: true
      directives:
        connect_src: "'self' http://localhost:* http://127.0.0.1:* ws://localhost:* wss://localhost:* ws://127.0.0.1:* https://snowplow.trx.gitlab.net/"