src/site/xdoc/quickstart.xml - logging-log4php - Git at Google

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 <document xmlns="http://maven.apache.org/XDOC/2.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://maven.apache.org/XDOC/2.0 http://maven.apache.org/xsd/xdoc-2.0.xsd">

 	<properties>
 		<title>Quick start</title>
 	</properties>

 	<body>
 		<section name="Quick start">

 	  		<p>First, <a href="install.html">install Apache log4php</a>.</p>

   			<p>You may also like to read the <a href="docs/introduction.html">introduction chapter</a> to familiarise
   			yoursef with the basic concepts used throughout the documentation and examples.</p>

 			<subsection name="A trivial example">
 				<p>Just want logging to stdout?</p>

 <pre class="prettyprint linenums">
 include('Logger.php');
 $logger = Logger::getLogger("main");
 $logger->info("This is an informational message.");
 $logger->warn("I'm not feeling so good...");
 </pre>

 				<p>This produces the following output:</p>

 <pre>
 INFO - This is an informational message.
 WARN - I'm not feeling so good...
 </pre>

 			</subsection>

 			<subsection name="A simple example">
 				<p>This example shows how to configure log4php using an XML configuration file. The framework will be
 				configured to log messages to a file, but only those with level greater or equal to <code>WARN</code>.
 				</p>

 				<p>First, create a configuration file named <code>config.xml</code> containing:</p>

 <pre class="prettyprint linenums"><![CDATA[
 <configuration xmlns="http://logging.apache.org/log4php/">
     <appender name="myAppender" class="LoggerAppenderFile">
         <param name="file" value="myLog.log" />
     </appender>
     <root>
         <level value="WARN" />
         <appender_ref ref="myAppender" />
     </root>
 </configuration>
 ]]></pre>

 				<p>This configuration file does the following:</p>

 				<ul>
 				    <li><em>line 2</em>: Creates an appender named <code>myAppender</code> using appender class <code>
 					<a href="docs/appenders/file.html">LoggerAppenderFile</a></code> which is used for
 					logging to a file.</li>

 					<li><em>line 3</em>: Sets the <code>file</code> parameter, which tells the appender to which file to
 					write.</li>

 					<li><em>line 6</em>: Sets the root logger level to <code>WARN</code>. This means that logging requests
 					with the level lower than <code>WARN</code> will not be logged by the root logger.</li>

 					<li><em>line 7</em>: Links <code>myAppender</code> to the root logger so that all events recieved by the root
 					logger will be forwarded to <code>myAppender</code> and written into the log file.</li>
 				</ul>

 				<p>To try it out, run the following code:</p>

 <pre class="prettyprint linenums"><![CDATA[
 // Insert the path where you unpacked log4php
 include('log4php/Logger.php');

 // Tell log4php to use our configuration file.
 Logger::configure('config.xml');

 // Fetch a logger, it will inherit settings from the root logger
 $log = Logger::getLogger('myLogger');

 // Start logging
 $log->trace("My first message.");   // Not logged because TRACE < WARN
 $log->debug("My second message.");  // Not logged because DEBUG < WARN
 $log->info("My third message.");    // Not logged because INFO < WARN
 $log->warn("My fourth message.");   // Logged because WARN >= WARN
 $log->error("My fifth message.");   // Logged because ERROR >= WARN
 $log->fatal("My sixth message.");   // Logged because FATAL >= WARN
 ]]></pre>

 				<p>This will create a file named <code>myLog.log</code> containing the following output:</p>

 <pre><![CDATA[
 WARN - My fourth message.
 ERROR - My fifth message.
 FATAL - My sixth message.
 ]]></pre>

 			</subsection>

 			<subsection name="An advanced example">

 				<p>This example covers named loggers, layouts and best practices in object-oriented programming.</p>

 				<p>Create a configuration file named <code>config.xml</code> with the following content:</p>

 <pre class="prettyprint linenums"><![CDATA[
 <configuration xmlns="http://logging.apache.org/log4php/">

     <appender name="myConsoleAppender" class="LoggerAppenderConsole" />

     <appender name="myFileAppender" class="LoggerAppenderFile">
         <layout class="LoggerLayoutPattern">
             <param name="conversionPattern" value="%date [%logger] %message%newline" />
         </layout>
         <param name="file" value="myLog.log" />
     </appender>

     <logger name="Foo">
         <appender_ref ref="myFileAppender" />
     </logger>

     <root>
         <level value="DEBUG" />
         <appender_ref ref="myConsoleAppender" />
     </root>
 </configuration>
 ]]></pre>

 				<p>The configuration defines two appenders: one writes to the console, and the other to a file.</p>

 				<p>The
 				console appender doesn't have a layout defined, so it will revert to default layout
 				(<code><a href="docs/layouts/simple.html">LoggerLayoutSimple</a></code>). The
 				file appender uses a different layout
 				(<code><a href="docs/layouts/pattern.html">LoggerLayoutPattern</a></code>)
 				which will result in different formatting of the logging
 				events.</p>

 				<p>The console appender is linked to the root logger. The file appender is linked to the logger named
 				<code>Foo</code>, however <code>Foo</code> also inherits appenders from the root logger (in this case
 				the console appender). This means that logging events sent to the <code>Foo</code> logger will be
 				logged both to the console and the file.</p>

 				<p>Consider the following code snippet:</p>

 <pre class="prettyprint linenums"><![CDATA[
 // Include and configure log4php
 include('log4php/Logger.php');
 Logger::configure('config.xml');

 /**
  * This is a classic usage pattern: one logger object per class.
  */
 class Foo
 {
     /** Holds the Logger. */
     private $log;

     /** Logger is instantiated in the constructor. */
     public function __construct()
     {
         // The __CLASS__ constant holds the class name, in our case "Foo".
         // Therefore this creates a logger named "Foo" (which we configured in the config file)
         $this->log = Logger::getLogger(__CLASS__);
     }

     /** Logger can be used from any member method. */
     public function go()
     {
         $this->log->info("We have liftoff.");
     }
 }

 $foo = new Foo();
 $foo->go();
 ]]></pre>

   					<p>This produces the following output in the console:</p>
 					<pre>INFO - We have liftoff.</pre>

 					<p>And the following in the log file:</p>
 					<pre>01/06/11 18:43:39,545 [5428] INFO Foo - We have liftoff.</pre>

 					<p>Note the different layout, this is because LoggerLayoutTTCC was used as layout for the file appender.</p>
 			</subsection>

 		</section>
 	</body>
 </document>
	<?xml version="1.0" encoding="UTF-8"?>
	<!--
	Licensed to the Apache Software Foundation (ASF) under one or more
	contributor license agreements. See the NOTICE file distributed with
	this work for additional information regarding copyright ownership.
	The ASF licenses this file to You under the Apache License, Version 2.0
	(the "License"); you may not use this file except in compliance with
	the License. You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.
	-->
	<document xmlns="http://maven.apache.org/XDOC/2.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/XDOC/2.0 http://maven.apache.org/xsd/xdoc-2.0.xsd">

	<properties>
	<title>Quick start</title>
	</properties>

	<body>
	<section name="Quick start">

	<p>First, <a href="install.html">install Apache log4php</a>.</p>

	<p>You may also like to read the <a href="docs/introduction.html">introduction chapter</a> to familiarise
	yoursef with the basic concepts used throughout the documentation and examples.</p>

	<subsection name="A trivial example">
	<p>Just want logging to stdout?</p>

	<pre class="prettyprint linenums">
	include('Logger.php');
	$logger = Logger::getLogger("main");
	$logger->info("This is an informational message.");
	$logger->warn("I'm not feeling so good...");
	</pre>

	<p>This produces the following output:</p>

	<pre>
	INFO - This is an informational message.
	WARN - I'm not feeling so good...
	</pre>

	</subsection>

	<subsection name="A simple example">
	<p>This example shows how to configure log4php using an XML configuration file. The framework will be
	configured to log messages to a file, but only those with level greater or equal to <code>WARN</code>.
	</p>

	<p>First, create a configuration file named <code>config.xml</code> containing:</p>

	<pre class="prettyprint linenums"><![CDATA[
	<configuration xmlns="http://logging.apache.org/log4php/">
	<appender name="myAppender" class="LoggerAppenderFile">
	<param name="file" value="myLog.log" />
	</appender>
	<root>
	<level value="WARN" />
	<appender_ref ref="myAppender" />
	</root>
	</configuration>
	]]></pre>

	<p>This configuration file does the following:</p>

	<ul>
	<li><em>line 2</em>: Creates an appender named <code>myAppender</code> using appender class <code>
	<a href="docs/appenders/file.html">LoggerAppenderFile</a></code> which is used for
	logging to a file.</li>

	<li><em>line 3</em>: Sets the <code>file</code> parameter, which tells the appender to which file to
	write.</li>

	<li><em>line 6</em>: Sets the root logger level to <code>WARN</code>. This means that logging requests
	with the level lower than <code>WARN</code> will not be logged by the root logger.</li>

	<li><em>line 7</em>: Links <code>myAppender</code> to the root logger so that all events recieved by the root
	logger will be forwarded to <code>myAppender</code> and written into the log file.</li>
	</ul>

	<p>To try it out, run the following code:</p>

	<pre class="prettyprint linenums"><![CDATA[
	// Insert the path where you unpacked log4php
	include('log4php/Logger.php');

	// Tell log4php to use our configuration file.
	Logger::configure('config.xml');

	// Fetch a logger, it will inherit settings from the root logger
	$log = Logger::getLogger('myLogger');

	// Start logging
	$log->trace("My first message."); // Not logged because TRACE < WARN
	$log->debug("My second message."); // Not logged because DEBUG < WARN
	$log->info("My third message."); // Not logged because INFO < WARN
	$log->warn("My fourth message."); // Logged because WARN >= WARN
	$log->error("My fifth message."); // Logged because ERROR >= WARN
	$log->fatal("My sixth message."); // Logged because FATAL >= WARN
	]]></pre>

	<p>This will create a file named <code>myLog.log</code> containing the following output:</p>

	<pre><![CDATA[
	WARN - My fourth message.
	ERROR - My fifth message.
	FATAL - My sixth message.
	]]></pre>

	</subsection>

	<subsection name="An advanced example">

	<p>This example covers named loggers, layouts and best practices in object-oriented programming.</p>

	<p>Create a configuration file named <code>config.xml</code> with the following content:</p>

	<pre class="prettyprint linenums"><![CDATA[
	<configuration xmlns="http://logging.apache.org/log4php/">

	<appender name="myConsoleAppender" class="LoggerAppenderConsole" />

	<appender name="myFileAppender" class="LoggerAppenderFile">
	<layout class="LoggerLayoutPattern">
	<param name="conversionPattern" value="%date [%logger] %message%newline" />
	</layout>
	<param name="file" value="myLog.log" />
	</appender>

	<logger name="Foo">
	<appender_ref ref="myFileAppender" />
	</logger>

	<root>
	<level value="DEBUG" />
	<appender_ref ref="myConsoleAppender" />
	</root>
	</configuration>
	]]></pre>

	<p>The configuration defines two appenders: one writes to the console, and the other to a file.</p>

	<p>The
	console appender doesn't have a layout defined, so it will revert to default layout
	(<code><a href="docs/layouts/simple.html">LoggerLayoutSimple</a></code>). The
	file appender uses a different layout
	(<code><a href="docs/layouts/pattern.html">LoggerLayoutPattern</a></code>)
	which will result in different formatting of the logging
	events.</p>

	<p>The console appender is linked to the root logger. The file appender is linked to the logger named
	<code>Foo</code>, however <code>Foo</code> also inherits appenders from the root logger (in this case
	the console appender). This means that logging events sent to the <code>Foo</code> logger will be
	logged both to the console and the file.</p>

	<p>Consider the following code snippet:</p>

	<pre class="prettyprint linenums"><![CDATA[
	// Include and configure log4php
	include('log4php/Logger.php');
	Logger::configure('config.xml');

	/**
	* This is a classic usage pattern: one logger object per class.
	*/
	class Foo
	{
	/** Holds the Logger. */
	private $log;

	/** Logger is instantiated in the constructor. */
	public function __construct()
	{
	// The __CLASS__ constant holds the class name, in our case "Foo".
	// Therefore this creates a logger named "Foo" (which we configured in the config file)
	$this->log = Logger::getLogger(__CLASS__);
	}

	/** Logger can be used from any member method. */
	public function go()
	{
	$this->log->info("We have liftoff.");
	}
	}

	$foo = new Foo();
	$foo->go();
	]]></pre>

	<p>This produces the following output in the console:</p>
	<pre>INFO - We have liftoff.</pre>

	<p>And the following in the log file:</p>
	<pre>01/06/11 18:43:39,545 [5428] INFO Foo - We have liftoff.</pre>

	<p>Note the different layout, this is because LoggerLayoutTTCC was used as layout for the file appender.</p>
	</subsection>

	</section>
	</body>
	</document>