includes/debug/logger/Factory.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21
  22 /**
  23  * PSR-3 logger instance factory.
  24  *
  25  * Creation of \Psr\Log\LoggerInterface instances is managed via the
  26  * MWLoggerFactory::getInstance() static method which in turn delegates to the
  27  * currently registered service provider.
  28  *
  29  * A service provider is any class implementing the MWLoggerSpi interface.
  30  * There are two possible methods of registering a service provider. The
  31  * MWLoggerFactory::registerProvider() static method can be called at any time
  32  * to change the service provider. If MWLoggerFactory::getInstance() is called
  33  * before any service provider has been registered, it will attempt to use the
  34  * $wgMWLoggerDefaultSpi global to bootstrap MWLoggerSpi registration.
  35  * $wgMWLoggerDefaultSpi is expected to be an array usable by
  36  * ObjectFactory::getObjectFromSpec() to create a class.
  37  *
  38  * @see MWLoggerSpi
  39  * @since 1.25
  40  * @author Bryan Davis <bd808@wikimedia.org>
  41  * @copyright © 2014 Bryan Davis and Wikimedia Foundation.
  42  */
  43 class MWLoggerFactory {
  44
  45         /**
  46          * Service provider.
  47          * @var MWLoggerSpi $spi
  48          */
  49         private static $spi;
  50
  51
  52         /**
  53          * Register a service provider to create new \Psr\Log\LoggerInterface
  54          * instances.
  55          *
  56          * @param MWLoggerSpi $provider Provider to register
  57          */
  58         public static function registerProvider( MWLoggerSpi $provider ) {
  59                 self::$spi = $provider;
  60         }
  61
  62
  63         /**
  64          * Get the registered service provider.
  65          *
  66          * If called before any service provider has been registered, it will
  67          * attempt to use the $wgMWLoggerDefaultSpi global to bootstrap
  68          * MWLoggerSpi registration. $wgMWLoggerDefaultSpi is expected to be an
  69          * array usable by ObjectFactory::getObjectFromSpec() to create a class.
  70          *
  71          * @return MWLoggerSpi
  72          * @see registerProvider()
  73          * @see ObjectFactory::getObjectFromSpec()
  74          */
  75         public static function getProvider() {
  76                 if ( self::$spi === null ) {
  77                         global $wgMWLoggerDefaultSpi;
  78                         $provider = ObjectFactory::getObjectFromSpec(
  79                                 $wgMWLoggerDefaultSpi
  80                         );
  81                         self::registerProvider( $provider );
  82                 }
  83                 return self::$spi;
  84         }
  85
  86
  87         /**
  88          * Get a named logger instance from the currently configured logger factory.
  89          *
  90          * @param string $channel Logger channel (name)
  91          * @return \Psr\Log\LoggerInterface
  92          */
  93         public static function getInstance( $channel ) {
  94                 if ( !interface_exists( '\Psr\Log\LoggerInterface' ) ) {
  95                         $message = <<<TXT
  96 MediaWiki requires the <a href="https://github.com/php-fig/log">PSR-3 logging library</a> to be present. This library is not embedded directly in MediaWiki's git repository and must be installed separately by the end user.
  97
  98 Please see <a href="https://www.mediawiki.org/wiki/Download_from_Git#Fetch_external_libraries">mediawiki.org</a> for help on installing the required components.
  99 TXT;
 100                         echo $message;
 101                         trigger_error( $message, E_USER_ERROR );
 102                         die( 1 );
 103                 }
 104
 105                 return self::getProvider()->getLogger( $channel );
 106         }
 107
 108
 109         /**
 110          * Construction of utility class is not allowed.
 111          */
 112         private function __construct() {
 113                 // no-op
 114         }
 115 }