Hagakure – Yet Another Error Reporter

Have you ever seen an error log like the one below?

PHP Fatal error: Allowed memory size of xxxxxx bytes exhausted (tried to allocate xxx bytes) in /var/www/wordpress/wp-includes/wp-db.php on line 2007

This means that PHP memory limit is exhausted while retrieving data from a database. In any case, this happens when your site has big data and makes insane loops inside.

But we want to know that which plugin tried to retrieve data?

Hagakure adds extra information to error.log file when wp-db.php causes memory limit error:

[08-May-2019 10:28:37 UTC] wpdb Error Backtrace: #1 Kunoichi\Hagakure\DbLogger->filter_query() /app/public/wp-includes/class-wp-hook.php Line 286 #2 WP_Hook->apply_filters() /app/public/wp-includes/plugin.php Line 208 #3 apply_filters /app/public/wp-includes/wp-db.php Line 1871 #4 wpdb->query() /app/public/wp-includes/wp-db.php Line 2579 #5 wpdb->get_results() /app/public/wp-includes/class-wp-query.php Line 2979 #6 WP_Query->get_posts() /app/public/wp-includes/class-wp-query.php Line 3387 #7 WP_Query->query() /app/public/wp-includes/post.php Line 1961 #8 get_posts /app/public/wp-content/plugins/hagakure/hagakure.php Line 34 #9 {closure} /app/public/wp-includes/class-wp-hook.php Line 286 #10 WP_Hook->apply_filters() /app/public/wp-includes/class-wp-hook.php Line 310 #11 WP_Hook->do_action() /app/public/wp-includes/plugin.php Line 465 #12 do_action /app/public/wp-includes/template-loader.php Line 13 #13 require_once /app/public/wp-blog-header.php Line 19 #14 require /app/public/index.php Line 17 #15 URI: /?p=1

This log will always follow the memory limit Fatal Error by wp-db.php. Now you can find #8 calls get_posts repeatedly.

We recommend watching logs with notification services like CloudWatch Logs. This error occurs in the productional environment, and you may not have a chance to see it occurs. We use Hagakure with our hosting service, please look forward to seeing our blog published and describing the integration!

This plugin also adds debug backtrace to error logs. To modify the error level to a detailed backtrace, define the constant in wp-config.php or somewhere else:

define( 'HAGAKURE_ERROR_LEVEL', E_NOTICE | E_USER_WARNING | E_WARNING | E_USER_ERROR );

Besides that, if SAVEQUERIES is set true, the slow query log will be logged with PHP debug backtrace. This helps you to debug.

Acknowledgements

The base text for dummy content is “Three Ghost Story” by Charles Dickens. The text file is modified the one of Project Gutenberg.