Bug 1867126 - automatic page load instrumentation

[rosahbruno]

Description

Configure auto instrumentation for page_load events.

Built-in page_load events can now be recorded in 2 ways

1. Automatically via the enableAutoPageLoadEvents parameter in the Glean configuration object. Whenever this is set to true, page load events will be collected automatically whenever initialize is called.
2. Manually via the @mozilla/glean/metrics object. We now expose pageLoad which is a function that a user can call at any time to record the same page load event that would have been collected automatically.

Automatic instrumentation

Glean.initialize("app-name", true, { enableAutoPageLoadEvents: true });

Example: https://debug-ping-preview.firebaseapp.com/pings/glean-from-website/9f6996dc-a336-46eb-8c93-a1278046ae10#L10

Manually call page_load

import GleanMetrics from "@mozilla/glean/metrics";

// ...

GleanMetrics.pageLoad({
  // Any of the values can be overwritten. If they are not overwritten,
  // the values pulled from the browser will be used.
  //
  // If `enableAutoPageLoadEvents` is true, then this call is a no-op.
  title: "Title Override"
});

Example: https://debug-ping-preview.firebaseapp.com/pings/glean-from-website/81fd045b-c8da-4229-8464-2860b054ece7#L10

Pull Request checklist

• Quality: Make sure this PR builds and runs cleanly.
  • Inside the glean/ folder, run:
    • npm run test Runs all tests
    • npm run lint Runs all linters
• Tests: This PR includes thorough tests or an explanation of why it does not
• Changelog: This PR includes a changelog entry to CHANGELOG.md or an explanation of why it does not need one
• Documentation: This PR includes documentation changes, an explanation of why it does not need that or a follow-up bug has been filed to do that work
  • Documentation should be added to The Glean Book when making changes to Glean's user facing API
    • When changes to the Glean Book are necessary, link to the corresponding PR on the mozilla/glean repository
  • Documentation should be added to the Glean.js developer documentation when making internal code changes

[kirill-demtchouk]

Love this! ❤️