class Praxigento_Module_Logger
{
    private static $_isLog4phpUsed = null;
    private $_loggerLog4php;
    private $_name;

    function __construct($name)
    {
        /**
         * switch off/on error reporting to prevent messages like
         * "ERR (3): Warning: include(Praxigento\Log\Logger.php): failed to open stream: No such file or directory"
         * in case of Praxigento_Log module is not used.
         */
        $level = error_reporting(0);
        self::$_isLog4phpUsed = class_exists('Praxigento_Log_Logger', true);
        error_reporting($level);
        if (self::$_isLog4phpUsed) {
            $this->_loggerLog4php = Praxigento_Log_Logger::getLogger($name);
        } else {
            $this->_name = is_object($name) ? get_class($name) : (string)$name;
        }
    }

    /**
     * Override getter to use '$log = Praxigento_Log_Logger::getLogger($this)' form in Mage classes.
     */
    public static function getLogger($name)
    {
        $class = __CLASS__;
        return new $class($name);
    }

    public function debug($message, $throwable = null)
    {
        $this->doLog($message, $throwable, 'debug', Zend_Log::INFO);
    }

    /**
     * Internal dispatcher for the called log method.
     */
    private function doLog($message, $throwable, $log4phpMethod, $zendLevel)
    {
        if (self::$_isLog4phpUsed) {
            $this->_loggerLog4php->$log4phpMethod($message, $throwable);
        } else {
            Mage::log($this->_name . ': ' . $message, $zendLevel);
            if ($throwable instanceof Exception) {
                Mage::logException($throwable);
            }
        }
    }

    public function error($message, $throwable = null)
    {
        $this->doLog($message, $throwable, 'error', Zend_Log::ERR);
    }

    public function fatal($message, $throwable = null)
    {
        $this->doLog($message, $throwable, 'fatal', Zend_Log::CRIT);
    }

    public function info($message, $throwable = null)
    {
        $this->doLog($message, $throwable, 'info', Zend_Log::NOTICE);
    }

    public function trace($message, $throwable = null)
    {
        $this->doLog($message, $throwable, 'trace', Zend_Log::DEBUG);
    }

    public function warn($message, $throwable = null)
    {
        $this->doLog($message, $throwable, 'warn', Zend_Log::WARN);
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<configuration xmlns="http://logging.apache.org/log4php/">
    <!-- ***********************************************************************************************
        THIS IS SAMPLE CONFIGURATION THAT WILL BE REWRITTEN ON REINSTALL.
        DON'T USE THIS FILE IN YOUR CONFIGURATION. MAKE A COPY TO "app/etc/log4php.cfg.xml" AND CHANGE
        "SYSTEM / CONFIGURATION / DEVELOPER / LOG SETTINGS / LOG4PHP CONFIG FILE NAME" VALUE
    *********************************************************************************************** -->

    <!--
            Available log levels:
                ALL -> TRACE -> DEBUG -> INFO -> WARN -> ERROR -> FATAL -> OFF
            Available appenders:
                http://logging.apache.org/log4php/docs/appenders.html
                appenders/LoggerAppenderMemory
            Available layouts:
                http://logging.apache.org/log4php/docs/layouts.html
    -->

    <!-- default appender -->
    <appender name="fileDefault" class="LoggerAppenderFile">
        <layout class="LoggerLayoutPattern">
            <param name="conversionPattern" value="%d{Y/m/d H:i:s,u} %p %c{2}: %m%n"/>
        </layout>
        <param name="file" value="/absolute/path/to/file/log4php.log"/>
        <param name="append" value="true"/>
    </appender>

    <!-- In-memory log for Adminhtml (backend sync output) -->
    <appender name="memoryDefault" class="LoggerAppenderMemory" threshold="DEBUG">
        <layout class="LoggerLayoutPattern">
            <param name="conversionPattern" value="%date{H:i:s,u} %p %c{2}: %msg%n"/>
        </layout>
    </appender>

    <!-- ERROR mail appender -->
    <appender name="emailError" class="LoggerAppenderMail">
        <layout class="LoggerLayoutPattern">
            <param name="conversionPattern" value="%d{Y/m/d H:i:s,u} %p %c{2}: %m%n"/>
        </layout>
        <param name="to" value="comma-separeted@emails.com"/>
        <param name="from" value="project-name@praxigento.com"/>
        <filter class="LoggerFilterLevelRange">
            <param name="levelMin" value="ERROR"/>
            <param name="levelMax" value="FATAL"/>
        </filter>
    </appender>

    <!-- root logger -->
    <root>
        <appender_ref ref="fileDefault"/>
        <appender_ref ref="memoryDefault"/>
        <appender_ref ref="emailError"/>
        <level value="ALL"/>
    </root>

</configuration>