Using Logs in PHP - Log4PHP

Hello

Logging is a must for development and production enviroments.
Log4PHP is a logger for php (log4net exist for .net , log4j for java , .....)

download the sources from https://logging.apache.org/log4php/download.html
install src/main/php into your project. 


Sample code 1

1. include('log4php/Logger.php');
2. $logger = Logger::getLogger("main");
3. $logger->info("This is an informational message.");
4. $logger->warn("I'm not feeling so good...");

remark : here i copy it to a folder name Log4php

this result in :

Sample code 2

First, create a configuration file named config.xml containing:

<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>

This configuration file does the following:

• line 2: Creates an appender named myAppender using appender class LoggerAppenderFile which is used for logging to a file.
• line 3: Sets the file parameter, which tells the appender to which file to write.
• line 6: Sets the root logger level to WARN. This means that logging requests with the level lower thanWARN will not be logged by the root logger.
• line 7: Links myAppender to the root logger so that all events recieved by the root logger will be forwarded to myAppender and written into the log file.
• 
  

Put this file at the same directory as your PHP project

To try it out, run the following code:

// 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

This result in myLog.log created as follows :

Sample code 3

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

Create a configuration file named config.xml with the following content:

<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>

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

The console appender doesn't have a layout defined, so it will revert to default layout (LoggerLayoutSimple). The file appender uses a different layout (LoggerLayoutPattern) which will result in different formatting of the logging events.

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

Consider the following code snippet:

// 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();

The output to file is as follows :

code for sample code 3 

Sample code 4

use rolling file with file name and line number
this appender fills the first file until maxFileSize [MB] then it copy the file to <file_name>1, after the second time it is to  <file_name>2 and this is maxBackupIndex times. after this the file is copy to  <file_name>1 and it start over again

Config.xml
<configuration xmlns="http://logging.apache.org/log4php/">
  <appender name="myAppenderRollingFile" class="LoggerAppenderRollingFile">
        <layout class="LoggerLayoutPattern">
            <param name="conversionPattern" value="%date %file : %line [%logger] %message%newline" />
        </layout>
        <param name="file" value="E:\wamp\www\TryLogger4PHP\file.log" />
        <param name="maxFileSize" value="1MB" />
        <param name="maxBackupIndex" value="5" />
    </appender>
 
<root>
        <level value="ERROR" />
        <appender_ref ref="myAppenderRollingFile" />
    </root>

  </configuration>

remarks

• one must use full path for file due to Log4PHP bug
• maxFileSize - max size of file
• maxBackupIndex - number of backup file

php file
<?php
// Include and configure 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

?>

output :

code for sample code 4




References :

• https://logging.apache.org/log4php/

Nathan