New in Symfony: Streamlined Log Files

Which Information is Missing?

Newer Symfony versions no longer log the information of the event channel, which produced messages like these:

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event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\DebugHandlersListener::configure". [] []
event.DEBUG: Notified event "kernel.request" to listener "Symfony\Component\HttpKernel\EventListener\ProfilerListener::onKernelRequest". [] []
...

We did this by changing the default configuration of the Symfony Standard edition:

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# app/config/config_dev.yml

# BEFORE
monolog:
    handlers:
        main:
            type: stream
            path: "%kernel.logs_dir%/%kernel.environment%.log"
            level: debug

# AFTER
monolog:
    handlers:
        main:
            type: stream
            path: "%kernel.logs_dir%/%kernel.environment%.log"
            level: debug
            channels: [!event]

The ! prefix tells Monolog to log all channels except event. You can exclude more channels (e.g. channels: [!event, !doctrine]) and you can leave it empty to start logging event messages again.

In addition, this change can be applied to all your existing Symfony applications, regardless of the Symfony version they use. Just add channels: [!event] to your Monolog configuration in config_dev.yml and say goodbye to those annoying log messages.

Improving Your Logs

Monolog, the library used by Symfony to log contents through the MonologBundle, is still heavily underused by most Symfony developers. As this article shows, even a minor configuration change can have a positive impact in your development experience. Don't forget to check out the documentation to learn:

• How to log messages to different files, which is useful to store the messages from some channels in log files different than `dev.log` and `prod.log`.
• How to easily create new log channels, so you can process those messages differently or store them in separate files.
• How to inject a preconfigured logger into services so the generated messages are logged in the given channel.