How to Log Messages to different Files
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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 logger service (monolog.logger.XXX)
in the container (use the php bin/console debug:container monolog command
to see a full list) and those are injected into different services.
Switching a Channel to a different Handler
Now, suppose you want to log the security channel to a different file.
To do this, just create a new handler and configure it to log only messages
from the security channel. You might add this in config.yml to log
in all environments, or just config_prod.yml to happen only in prod:
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# app/config/config.yml
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.
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
You can also configure additional channels without the need to tag your services:
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# app/config/config.yml
monolog:
channels: ['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.