```ruby
# frozen_string_literal: true

require "logger"
require "justimmo_client/core/config"

module JustimmoClient
  # Logging support
  module Logging
    class << self
      # Use the Rails or default logger if none is set.
      # @!attribute [rw] logger
      # @return [Logger]
      def logger
        @logger ||= rails_logger || default_logger
      end

      attr_writer :logger

      def default_logger
        logger = Logger.new($stdout)
        logger.level = JustimmoClient::Config.debug ? Logger::DEBUG : Logger::INFO
        logger
      end

      # The Ruby on Rails logger
      # @return [Logger, nil] The logger object
      def rails_logger
        if ("true" == ENV.fetch("JUSTIMMO_USE_RAILS_LOGGER", "true")) && defined?(::Rails)
          ::Rails&.logger
        end
      end
    end

    def logger
      Logging.logger
    end

    alias log logger
  end
end
```

Change log format for default logger
user
```ruby
# frozen_string_literal: true

require "logger"
require "justimmo_client/core/config"

module JustimmoClient
  # Logging support
  module Logging
    class << self
      # Use the Rails or default logger if none is set.
      # @!attribute [rw] logger
      # @return [Logger]
      def logger
        @logger ||= rails_logger || default_logger
      end

      attr_writer :logger

      def default_logger
        logger = Logger.new($stdout)
        logger.level = JustimmoClient::Config.debug ? Logger::DEBUG : Logger::INFO
        logger.datetime_format = "%Y-%m-%d %H:%M:%S"
        logger.progname = "JustimmoClient"
        logger.formatter = proc do |severity, datetime, progname, message|
          "[#{format("%-5s", severity)}]  #{datetime}  #{progname}  #{message}\n"
        end
        logger
      end

      # The Ruby on Rails logger
      # @return [Logger, nil] The logger object
      def rails_logger
        if ("true" == ENV.fetch("JUSTIMMO_USE_RAILS_LOGGER", "true")) && defined?(::Rails)
          ::Rails&.logger
        end
      end
    end

    def logger
      Logging.logger
    end

    alias log logger
  end
end
```
assistant