Host Google Fonts - Measure time

[jeawhanlee]

Context
The Host Google Fonts feature presents a risk to slow down the loading of the page, during preload for instance. We must have a way to measure the impact of the feature on processing time.

Expected behavior
We must be able to retrieve logs (typically when WPR DEBUG is enabled) about:

• Time it takes to run the Host Google Fonts feature when processing a new page
• Details about the time taken for main steps of the process. We expect the risk to come from downloading the fonts and CSS so those two steps should be measured. Other steps could be measured too if it seems relevant.

You can check this to see how to add logs.

Acceptance Criteria
I can retrieve logs about how long it takes to process the Host Google Fonts feature on a page:

• Activate the logs
• Browse a page that has not been preloaded yet, nor has Google Fonts optimization ready yet (no files downloaded, etc).
• Check the logs: the total execution time of Google Fonts, as well as time to download the CSS files and the time to download the fonts must be available.

When logs are deactivated, timing measurments must not happen.

[jeawhanlee]

Scope a solution ✅

• In

  wp-rocket/inc/Engine/Media/Fonts/Frontend/Controller.php

  Line 68 in 3ff897b

  public function rewrite_fonts( $html ): string {

  • Add a start time and end time, then log the difference to get the time taken for the Google Fonts Optimzation process to complete.
  • As for the download execution log, we already have this here:
    

    wp-rocket/inc/Engine/Media/Fonts/Filesystem.php

    Line 107 in 3201ce5

    Logger::debug( "Font download and optimization duration in seconds -- $duration", [ 'Host Fonts Locally' ] );

    
    However we'll need to output it in a readable format.

Estimate the effort ✅

[XS]

[Miraeld]

Looks good to me.

[DahmaniAdame]

It will be good to add the number of fonts processed to have a correlation between the two. This will help support anticipate the potential impact just by checking the number of fonts without activating the log.