How to Log Messages to different Files
The Symfony Framework organizes log messages into channels. By default, there
are several channels, including doctrine, event, security, request
and more. The channel is printed in the log message and can also be used
to direct different channels to different places/files.
By default, Symfony logs every message into a single file (regardless of the channel).
Note
Each channel corresponds to a different logger service (monolog.logger.XXX)
Use the php bin/console debug:container monolog command to see a full
list of services and learn how to autowire monolog channels.
Switching a Channel to a different Handler
Now, suppose you want to log the security channel to a different file.
To do this, create a new handler and configure it to log only messages
from the security channel. The following example does that only in the
prod configuration environment:
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# config/packages/monolog.yaml
when@prod:
monolog:
handlers:
security:
# log all messages (since debug is the lowest level)
level: debug
type: stream
path: '%kernel.logs_dir%/security.log'
channels: [security]
# an example of *not* logging security channel messages for this handler
main:
# ...
# channels: ['!security']Caution
The channels configuration only works for top-level handlers. Handlers
that are nested inside a group, buffer, filter, fingers crossed or other
such handler will ignore this configuration and will process every message
passed to them.
You can specify the configuration in different ways:
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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
You can also configure additional channels without the need to tag your services:
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# config/packages/monolog.yaml
monolog:
channels: ['foo', 'bar', 'foo_bar']Symfony automatically registers one service per channel (in this example, the
channel foo creates a service called monolog.logger.foo). In order to
inject this service into others, you must update the service configuration to
choose the specific service to inject.
How to Autowire Logger Channels
Starting from MonologBundle 3.5 you can autowire different Monolog channels
by type-hinting your service arguments with the following syntax:
Psr\Log\LoggerInterface $<camelCased channel name> + Logger. The <channel>
must have been predefined in your Monolog configuration.
For example to inject the service related to the foo_bar logger channel,
change your constructor like this:
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- public function __construct(LoggerInterface $logger)
+ public function __construct(LoggerInterface $fooBarLogger)
{
$this->logger = $fooBarLogger;
}Configure Logger Channels with Attributes
Starting from Monolog 3.5 you can also configure the logger channel
by using the #[WithMonologChannel] attribute directly on your service
class:
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// src/Service/MyFixtureService.php
namespace App\Service;
use Monolog\Attribute\WithMonologChannel;
use Psr\Log\LoggerInterface;
use Symfony\Bridge\Monolog\Logger;
#[WithMonologChannel('fixtures')]
class MyFixtureService
{
public function __construct(LoggerInterface $logger)
{
// ...
}
}This way you can avoid declaring your service manually to use a specific channel.
3.5
The #[WithMonologChannel] attribute was introduced in Monolog 3.5.0.
