A drop-in profiler for WordPress in the form of a MU (Must Use) plugin

Links

Instructions

Place 0_wordpress_profiler.php in the WordPress installation's mu-plugins folder
Access the troublesome parts of the site or just let it sit and collect reports. One of the project goals has been to make an unsupervised monitoring system/agent.
Go to the wp-content (or where ever you have set the content folder to be)/profiler and review the reports

Tip: It is named 0_wordpress_profiler.php so that the filesystem will ideally return it 1st in a list of files, so please avoid any other mu plugins starting with 0 :). OS configuration files in Linux use the same technique.

The following collectors are supported

Hooks

The following data for each hook are recorded:

The hook
The time started
The time stopped
The calculated time that was taken
The calculated time as a string without scientific notation taken
The memory usage when starting
The memory usage when stopping
The computed memory use that was taken
The functions called in the given instance of the hook run if the function collector is enabled
The caller function of the hook as provided by debug_backtrace if the function tracing collector is enabled
The children hooks (nested hook calls) in the same structure as above

Functions

Inside the hook data, a function key will exist with an array of functions. Each element has the following:

The time started
the time stopped
The calculated time that was taken
The calculated time as a string without scientific notation taken
The memory usage when starting
The memory usage when stopping
The calculated memory use that was taken

Function tracing

Function tracing will provide a caller key in a hook with the output of debug_backtrace. It is is off by default due to the possible performance hit of using debug_backtrace() on every hooked-in function. If you wish to use it, call wp_profiler()->enable_collector(\WPProfiler\Core\Collectors\FunctionTracer::NAME).

Query data

This will scan and output the results of all is_* functions in $the_wp_query, the key being the method name, and the value the result.

Request data

This makes a copy of $wp->query_vars.

Db

Even when this collector is enabled, it will only work when SAVEQUERIES WordPress constant is enabled. It relies on $wpdb->queries, and the output is a customized format mapped from the resulting arrays of wpdb::log_query. See example.json for reference to the format.

Example hook report

Here is a sample of a report generated from this plugin: example.json

Use a custom report handler

The profiler supports setting a custom handler for the report data via the set_report_handler method. This requires a class implement against the ReporterInterface interface.

Example custom report handler

use WPProfiler\Core\ReporterInterface;
class MyCustomReporter implements ReporterInterface {
   public function execute( $filename, array $data ) {
      wp_remote_post( 'https://myreport.server', [ 'body' => [ 'filename' => $filename, 'data' => $data ] ] );
   }
}
wp_profiler()->set_report_handler( new MyCustomReporter() );

Creating your own Collector

You can create a new collector at any time during the WordPress lifecycle, assuming it is after WPProfiler has loaded.

Implement the \WPProfiler\Core\CollectorInterface interface or extend the \WPProfiler\Core\CollectorAbstract class to use the base collector shared by all the core collectors.

Example:

use WPProfiler\Core\CollectorInterface;
use WPProfiler\Core\Profiler;
class MyCollector implements CollectorInterface {
   public function __construct( Profiler $profiler ) {
   }
   public function init() {
      // TODO: Implement init() method.
   }
   public function get( $data = null ) {
   }
   public function enable() {
      // TODO: Implement enable() method.
   }
   public function disable() {
      // TODO: Implement disable() method.
   }
}
wp_profiler()->register_collector('my_collector', new MyCollector(wp_profiler()));
wp_profiler()->enable_collector('my_collector');

Adding custom meta to the report

If you don't want to create a full-fleged collector and just want to send an extra piece of info with the report, the meta API (not post/user/term in WP core) will do the job. Example:

wp_profiler()->add_meta('operating_system','linux');

How to ignore a function from functional profiling

Use the ignore function API on the function collector. See example:

use WPProfiler\Core\Collectors\Function_;
function my_function() {
}
$my_function = function () {
};
class MyTest {
    public static function my_static_function() {
    }
    public function my_function() {
    }
}
$my_object = new MyTest();
wp_profiler()->call_collector( Function_::NAME, 'set_ignoring_enabled', true );
wp_profiler()->call_collector( Function_::NAME, 'ignore_function', 'my_function' );
wp_profiler()->call_collector( Function_::NAME, 'ignore_function', $my_function );
wp_profiler()->call_collector( Function_::NAME, 'ignore_function', [ 'MyTest', 'my_static_function' ] );
wp_profiler()->call_collector( Function_::NAME, 'ignore_function', [ $my_object, 'my_function' ] );

How to ignore a hook from profiling

use WPProfiler\Core\Collectors\Hook;
wp_profiler()->call_collector( Hook::NAME, 'ignore_hook', 'my_custom_hook' );

API Documentation

See generated docs at apidocs.wpprofiler.org