Symfony / Monolog

config/services.yaml

•   # Show request info in log (URL, IP, referer, etc)
    monolog.processor.web:
      class: Monolog\Processor\WebProcessor
      tags:
        - { name: monolog.processor }
  
    # Include stack traces
    monolog.formatter.line:
      class: Monolog\Formatter\LineFormatter
      calls:
        - [includeStacktraces]

config/packages/prod/monolog.yaml

• monolog:
    handlers:
      # log rotation: https://symfony.com/doc/current/logging.html#how-to-rotate-your-log-files
      # mailing:      https://symfony.com/doc/current/logging/monolog_email.html
      # levels:       https://stackify.com/php-monolog-tutorial/
      main:
        # if *one* log entry is error or higher, pass *all* to file_log
        type: fingers_crossed
        #action_level: warning
        action_level: error
        # practically silences the log
        #action_level: alert
        excluded_http_codes: [404, 405]
        buffer_size: 100 # How many messages should be saved? Prevent memory leaks
        handler: grouped
        # That does not eliminate deprecation warnings
        #channels: [ "!deprecation" ]
      grouped:
        type: group
        #            members: [file_log, deduplicated]
        members: [file_log]
      file_log:
        #type: stream
        type:  rotating_file
        # max number of log files to keep
        # defaults to zero, which means infinite files
        max_files: 14
        #path: php://stderr
        path: "%kernel.logs_dir%/%kernel.environment%.log"
        #level: debug
        #level: warning
        level: error
        # practically silences the log
        #level: alert
        #formatter: monolog.formatter.json
        formatter: monolog.formatter.line
      #        deduplicated:
      #            type: deduplication
      #            handler: symfony_mailer
      #        symfony_mailer:
      #            type:         symfony_mailer
      #            from_email:   'log-errors@example.com'
      #            to_email:     'me@example.com'
      #            subject:      'An Error Occurred! %%message%%'
      #            level:        debug
      #            formatter:    monolog.formatter.html
      #            content_type: text/html
  
      #        phperrorlog:
      #            type: stream
      #            path: php://stderr
      #            level: notice
      console:
        type: console
        process_psr_3_messages: false
        channels: ["!event", "!doctrine"]
  

Disable logging:

• /config/packages/dev/monolog.yaml

  • monolog:
        handlers:
            main:
                # Quotes are important, otherwise interpreted as null "empty"
                type: 'null'

Custom Log

E.g. "i18n"

• config/packages/dev/monolog.yaml

  • monolog:
        channels:
            - deprecation # Deprecations are logged in the dedicated "deprecation" channel when it exists
            - i18n # Internationalization logs are logged in the dedicated "internationalization" channel when it exists
        handlers:
          i18n:
            type: stream
            path: "%kernel.logs_dir%/i18n.log"
            level: debug
            channels: ["i18n"]
    

• src/Service/I18nLoggerService.php

  • <?php
    namespace App\Service;
    
    use Psr\Log\LoggerInterface;
    
    // tail -f var/log/i18n.log
    
    // Used to log internationalization events
    class I18nLoggerService
    {
        public function __construct(private LoggerInterface $logger)
        {
        }
    
        public function log(string $message)
        {
            $this->logger->info($message);
        }
    }
    

• config/services.yaml

  • services:
      # Custom internationalization logger service into var/log/i18n.log
      App\Service\I18nLoggerService:
        arguments:
          $logger: '@monolog.logger.i18n'

• Use it with dependency injection

  • public function __construct(private I18nLoggerService $logger){
        $logger->log('Foo');
    }

    •