How to Log Messages to different Files

How to Log Messages to different Files

The Symfony Standard Edition contains a bunch of channels for logging: doctrine, event, security and request. Each channel corresponds to a logger service (monolog.logger.XXX) in the container and is injected to the concerned service. The purpose of channels is to be able to organize different types of log messages.

By default, Symfony logs every message into a single file (regardless of the channel).

Switching a Channel to a different Handler

Now, suppose you want to log the doctrine channel to a different file.

To do so, just create a new handler and configure it like this:

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    # app/config/config.yml
    monolog:
        handlers:
            main:
                type:     stream
                path:     /var/log/symfony.log
                channels: ["!doctrine"]
            doctrine:
                type:     stream
                path:     /var/log/doctrine.log
                channels: [doctrine]
    
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    <!-- app/config/config.xml -->
    <container xmlns="http://symfony.com/schema/dic/services"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:monolog="http://symfony.com/schema/dic/monolog"
        xsi:schemaLocation="http://symfony.com/schema/dic/services
            http://symfony.com/schema/dic/services/services-1.0.xsd
            http://symfony.com/schema/dic/monolog
            http://symfony.com/schema/dic/monolog/monolog-1.0.xsd"
    >
        <monolog:config>
            <monolog:handler name="main" type="stream" path="/var/log/symfony.log">
                <monolog:channels>
                    <monolog:channel>!doctrine</monolog:channel>
                </monolog:channels>
            </monolog:handler>
    
            <monolog:handler name="doctrine" type="stream" path="/var/log/doctrine.log">
                <monolog:channels>
                    <monolog:channel>doctrine</monolog:channel>
                </monolog:channels>
            </monolog:handler>
        </monolog:config>
    </container>
    
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    // app/config/config.php
    $container->loadFromExtension('monolog', array(
        'handlers' => array(
            'main'     => array(
                'type'     => 'stream',
                'path'     => '/var/log/symfony.log',
                'channels' => array(
                    '!doctrine',
                ),
            ),
            'doctrine' => array(
                'type'     => 'stream',
                'path'     => '/var/log/doctrine.log',
                'channels' => array(
                    'doctrine',
                ),
            ),
        ),
    ));
    

YAML Specification

You can specify the configuration by many forms:

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channels: ~    # Include all the channels

channels: foo  # Include only channel "foo"
channels: "!foo" # Include all channels, except "foo"

channels: [foo, bar]   # Include only channels "foo" and "bar"
channels: ["!foo", "!bar"] # Include all channels, except "foo" and "bar"

Creating your own Channel

You can change the channel monolog logs to one service at a time. This is done either via the configuration below or by tagging your service with monolog.logger and specifying which channel the service should log to. With the tag, the logger that is injected into that service is preconfigured to use the channel you've specified.

Configure Additional Channels without Tagged Services

2.4This feature was introduced to the MonologBundle 2.4, which was first packaged with Symfony 2.4.

With MonologBundle 2.4 you can configure additional channels without the need to tag your services:

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    # app/config/config.yml
    monolog:
        channels: ["foo", "bar"]
    
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    <!-- app/config/config.xml -->
    <container xmlns="http://symfony.com/schema/dic/services"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:monolog="http://symfony.com/schema/dic/monolog"
        xsi:schemaLocation="http://symfony.com/schema/dic/services
            http://symfony.com/schema/dic/services/services-1.0.xsd
            http://symfony.com/schema/dic/monolog
            http://symfony.com/schema/dic/monolog/monolog-1.0.xsd"
    >
        <monolog:config>
            <monolog:channel>foo</monolog:channel>
            <monolog:channel>bar</monolog:channel>
        </monolog:config>
    </container>
    
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    // app/config/config.php
    $container->loadFromExtension('monolog', array(
        'channels' => array(
            'foo',
            'bar',
        ),
    ));
    

With this, you can now send log messages to the foo channel by using the automatically registered logger service monolog.logger.foo.

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