How to Implement Custom Error Logging in WordPress

Logging is a crucial aspect of WordPress development, especially when debugging and tracking issues. In this guide, we'll show you how to implement a custom write_log() function in WordPress using error_log(), which allows you to log different types of messages (information, warnings, errors, and more).

Creating the Custom write_log() Function

The custom write_log() function leverages the built-in error_log() function to log various messages during development. This helps you track and resolve issues efficiently.

function write_log($message) {
    if (true === WP_DEBUG) {
        if (is_array($message) || is_object($message)) {
            error_log(print_r($message, true));
        } else {
            error_log($message);
        }
    }
}

How It Works

Here's a breakdown of the function:

• WP_DEBUG Check: Ensures the log messages are only written when WordPress debugging is enabled (set to true) in wp-config.php.
• Array/Object Logging: If the message is an array or object, it converts it into a readable string format using print_r().
• Scalar Logging: If it's a simple data type (e.g., string, integer, etc.), it logs the message directly.

Usage Example

You can use the write_log() function anywhere in your WordPress code to log messages for debugging:

function my_custom_function() {
    $data = array('foo' => 'bar', 'hello' => 'world');
    write_log('My custom message.');
    write_log($data);
}

Viewing the Log Messages

Make sure to enable debugging by adding the following lines in your wp-config.php file:

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);

Once enabled, WordPress will log the messages into an error log file, which can typically be found in your server's error log directory. If you want to specify a custom log file, you can modify the error_log directive in php.ini.

Best Practices for Debugging in WordPress

When using logging in WordPress, follow these best practices:

• Always disable debugging on production sites by setting WP_DEBUG to false.
• Use logging only for non-sensitive data to avoid exposing any personal information.
• Regularly clear your log files to avoid storing unnecessary data.

Related Resources

For further reading, here are some useful external links:

• WordPress error_log() Function Documentation
• WP_DEBUG Codex
• PHP error_log() Function Documentation

By using this custom logging technique, you'll be able to easily monitor your WordPress site and troubleshoot issues effectively during development.