Add logic for log level filtering to `WC_Log_Handler`.

includes/abstracts/abstract-wc-log-handler.php

@@ -3,6 +3,10 @@ if ( ! defined( 'ABSPATH' ) ) {
 	exit; // Exit if accessed directly
 }
 
+if ( ! class_exists( 'WC_Logger' ) ) {
+	include_once( dirname( dirname( __FILE__ ) ) . '/class-wc-logger.php' );
+}
+
 /**
  * Abstract WC Log Handler Class
  *
@@ -13,6 +17,47 @@ if ( ! defined( 'ABSPATH' ) ) {
  */
 abstract class WC_Log_Handler {
 
+	/**
+	 * Minimum log level this handler will process.
+	 *
+	 * @var int 0-8 minimum level severity for handling log entry.
+	 * @access private
+	 */
+	protected $_threshold;
+
+	/**
+	 * Log levels by severity.
+	 *
+	 * @var array
+	 * @access private
+	 */
+	protected static $_log_levels = array(
+		WC_Logger::DEBUG     => 0,
+		WC_Logger::INFO      => 1,
+		WC_Logger::NOTICE    => 2,
+		WC_Logger::WARNING   => 3,
+		WC_Logger::ERROR     => 4,
+		WC_Logger::CRITICAL  => 6,
+		WC_Logger::ALERT     => 7,
+		WC_Logger::EMERGENCY => 8,
+	);
+
+	/**
+	 * Constructor for log handler.
+	 *
+	 * @param arr $args {
+	 *     @type string $threshold Optional. Sets the log severity threshold.
+	 *         emergency|alert|critical|error|warning|notice|info|debug
+	 * }
+	 */
+	public function __construct( $args = array() ) {
+		if ( isset( $args['threshold'] ) ) {
+			$this->set_threshold( $args['threshold'] );
+		} else {
+			$this->set_threshold( WC_Logger::EMERGENCY );
+		}
+	}
+
 	/**
 	 * Handle a log entry.
 	 *
@@ -27,6 +72,41 @@ abstract class WC_Log_Handler {
 	 */
 	public abstract function handle( $level, $timestamp, $message, $context );
 
+	/**
+	 * Set handler severity threshold.
+	 *
+	 * @param string $level emergency|alert|critical|error|warning|notice|info|debug
+	 */
+	public function set_threshold( $level ) {
+		$level = apply_filters( 'woocommerce_log_handler_set_threshold', $level, __CLASS__ );
+		$this->_threshold = $this->get_level_severity( $level );
+	}
+
+	/**
+	 * Decode level string into integer.
+	 *
+	 * @param string $level emergency|alert|critical|error|warning|notice|info|debug
+	 * @return int 0 (debug) - 8 (emergency) or -1 if level is not valid
+	 */
+	public static function get_level_severity( $level ) {
+		if ( array_key_exists( $level, self::$_log_levels ) ) {
+			$severity = self::$_log_levels[ $level ];
+		} else {
+			$severity = -1;
+		}
+		return $severity;
+	}
+
+	/**
+	 * Should this handler process this log?
+	 *
+	 * @param string $level emergency|alert|critical|error|warning|notice|info|debug
+	 * @return bool true if the log should be handled.
+	 */
+	public function should_handle( $level ) {
+		return $this->_threshold <= $this->get_level_severity( $level );
+	}
+
 	/**
 	 * Formats a timestamp for use in log messages.
 	 *

includes/class-wc-logger.php

@@ -20,14 +20,14 @@ class WC_Logger {
 	 *
 	 * @see @link {https://tools.ietf.org/html/rfc5424}
 	 */
-	const EMERGENCY = 'emergency';
-	const ALERT     = 'alert';
-	const CRITICAL  = 'critical';
-	const ERROR     = 'error';
-	const WARNING   = 'warning';
-	const NOTICE    = 'notice';
-	const INFO      = 'info';
 	const DEBUG     = 'debug';
+	const INFO      = 'info';
+	const NOTICE    = 'notice';
+	const WARNING   = 'warning';
+	const ERROR     = 'error';
+	const CRITICAL  = 'critical';
+	const ALERT     = 'alert';
+	const EMERGENCY = 'emergency';
 
 	/**
 	 * Stores registered log handlers.
@@ -37,6 +37,17 @@ class WC_Logger {
 	 */
 	private $_handlers;
 
+	private static $_valid_levels = array(
+		self::DEBUG,
+		self::INFO,
+		self::NOTICE,
+		self::WARNING,
+		self::ERROR,
+		self::CRITICAL,
+		self::ALERT,
+		self::EMERGENCY,
+	);
+
 	/**
 	 * Constructor for the logger.
 	 */
@@ -74,6 +85,9 @@ class WC_Logger {
 	 * }
 	 */
 	public function log( $level, $message, $context = array() ) {
+		if ( ! in_array( $level, self::$_valid_levels ) ) {
+			_doing_it_wrong( __FUNCTION__, sprintf( __( 'WC_Logger::log was called with an invalid level "%s"', 'woocommerce' ), $level ), '2.8' );
+		}
 
 		$timestamp = current_time( 'timestamp' );
 

includes/log-handlers/class-wc-log-handler-file.php

@@ -28,8 +28,11 @@ class WC_Log_Handler_File extends WC_Log_Handler {
 
 	/**
 	 * Constructor for the logger.
+	 *
+	 * @param $args additional args. @see WC_Log_Handler::__construct
 	 */
-	public function __construct() {
+	public function __construct( $args ) {
+		parent::__construct( $args );
 		$this->_handles = array();
 	}
 
@@ -60,6 +63,10 @@ class WC_Log_Handler_File extends WC_Log_Handler {
 	 */
 	public function handle( $level, $timestamp, $message, $context ) {
 
+		if ( ! $this->should_handle( $level ) ) {
+			return true;
+		}
+
 		if ( isset( $context['tag'] ) && $context['tag'] ) {
 			$handle = $context['tag'];
 		} else {
@@ -70,13 +77,12 @@ class WC_Log_Handler_File extends WC_Log_Handler {
 
 		// Bubble if add is NOT successful
 		return ! $this->add( $entry, $handle );
-
 	}
 
 	/**
 	 * Builds a log entry text from level, timestamp and message.
 	 *
-	 * Attempt to ensure backwords compatibility for legacy WC_Logger::add calls
+	 * Attempt to ensure backwards compatibility for legacy WC_Logger::add calls
 	 *
 	 * @param string $level emergency|alert|critical|error|warning|notice|info|debug
 	 * @param int $timestamp

includes/wc-core-functions.php

@@ -1428,14 +1428,15 @@ function wc_get_logger() {
  *
  * @since 2.8
  * @param array $handlers
+ * @param string $threshold Optional. Threshold for log handler. Defaults to 'info'.
  * @return array
  */
-function wc_register_file_log_handler( $handlers ) {
+function wc_register_file_log_handler( $handlers, $threshold = 'info' ) {
 	if ( ! class_exists( 'WC_Log_Handler_File' ) ) {
 		include_once( dirname( __FILE__ ) . '/log-handlers/class-wc-log-handler-file.php' );
 	}
 
-	array_push( $handlers, new WC_Log_Handler_File() );
+	array_push( $handlers, new WC_Log_Handler_File( array( 'threshold' => $threshold ) ) );
 
 	return $handlers;
 }