WP Log Action

This plugin uses hooks in the opposite way most plugins do. You add do_action where you want to do some logging and this plugin will save it to the database only when active.

Log Activity

This plugin now logs plugin activity (when activated, deactivated, deleted, updated, installed), when wordpress is updated, and when functions are used wrong or deprecated.

Example:

do_action( 'wp_log_info', 'So far ok', 'Details of what is ok.' );
if ( $something_bad_happened ) {
    do_action( 'wp_log_error', 'This Happened!', 'Details of what happened.' );
    ...
}

See Tools->Logs to view, delete, and export the logs on the admin side. Only users with the manage_options capability will have access.

This plugin automatically logs deprecated and doing_it_wrong errors. The rest is what you add to your code.

You can log what functions will be run for a specific action or filter. For example if you want to see what runs in the ‘init’ hook:

function check_init_hook() {
    do_action( 'wp_log_debug_hook', 'init' );
}
add_filter( 'init', 'check_init_hook', 0 );

The following are the different levels of logging to add to your code. You can use any level how you see fit, the descriptions of each level are just guidelines.

Emergency

System is unusable
do_action( ‘wp_log_emergency’, $label, $message );

Alert

Action must be taken immediately.
do_action( ‘wp_log_alert’, $label, $message );

Critical

Critical conditions.
do_action( ‘wp_log_critical’, $label, $message );

Error

Runtime errors that do not require immediate action but should typically be logged and monitored.
do_action( ‘wp_log_error’, $label, $message );

Warning

Exceptional occurrences that are not errors.
do_action( ‘wp_log_warning’, $label, $message );

Notice

Normal but significant events.
do_action( ‘wp_log_notice’, $label, $message );

Info

Interesting events.
do_action( ‘wp_log_info’, $label, $message );

Debug

Detailed debug information.
do_action( ‘wp_log_debug’, $label, $message );