logger.rb

# frozen_string_literal: true

# Licensed to the Software Freedom Conservancy (SFC) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The SFC licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

require 'forwardable'
require 'logger'

module Selenium
  module WebDriver
    #
    # @example Enable full logging
    #   Selenium::WebDriver.logger.level = :debug
    #
    # @example Log to file
    #   Selenium::WebDriver.logger.output = 'selenium.log'
    #
    # @example Use logger manually
    #   Selenium::WebDriver.logger.info('This is info message')
    #   Selenium::WebDriver.logger.warn('This is warning message')
    #
    class Logger
      extend Forwardable

      def_delegators :@logger,
                     :close,
                     :debug?,
                     :info?,
                     :warn?,
                     :error?,
                     :fatal, :fatal?,
                     :level

      #
      # @param [String] progname Allow child projects to use Selenium's Logger pattern
      #
      def initialize(progname = 'Selenium', default_level: nil, ignored: nil, allowed: nil)
        default_level ||= $DEBUG || ENV.key?('DEBUG') ? :debug : :warn

        @logger = create_logger(progname, level: default_level)
        @ignored = Array(ignored)
        @allowed = Array(allowed)
        @first_warning = false
      end

      def level=(level)
        if level == :info && @logger.level == :info
          info(':info is now the default log level, to see additional logging, set log level to :debug')
        end

        @logger.level = level
      end

      #
      # Changes logger output to a new IO.
      #
      # @param [String] io
      #
      def output=(io)
        @logger.reopen(io)
      end

      #
      # Returns IO object used by logger internally.
      #
      # Normally, we would have never needed it, but we want to
      # use it as IO object for all child processes to ensure their
      # output is redirected there.
      #
      # It is only used in debug level, in other cases output is suppressed.
      #
      # @api private
      #
      def io
        @logger.instance_variable_get(:@logdev).dev
      end

      #
      # Will not log the provided ID.
      #
      # @param [Array, Symbol] ids
      #
      def ignore(*ids)
        @ignored += Array(ids).flatten
      end

      #
      # Will only log the provided ID.
      #
      # @param [Array, Symbol] ids
      #
      def allow(*ids)
        @allowed += Array(ids).flatten
      end

      #
      # Used to supply information of interest for debugging a problem
      # Overrides default #debug to skip ignored messages by provided id
      #
      # @param [String] message
      # @param [Symbol, Array<Symbol>] id
      # @yield see #deprecate
      #
      def debug(message, id: [], &block)
        discard_or_log(:debug, message, id, &block)
      end

      #
      # Used to supply information of general interest
      #
      # @param [String] message
      # @param [Symbol, Array<Symbol>] id
      # @yield see #deprecate
      #
      def info(message, id: [], &block)
        discard_or_log(:info, message, id, &block)
      end

      #
      # Used to supply information that suggests an error occurred
      #
      # @param [String] message
      # @param [Symbol, Array<Symbol>] id
      # @yield see #deprecate
      #
      def error(message, id: [], &block)
        discard_or_log(:error, message, id, &block)
      end

      #
      # Used to supply information that suggests action be taken by user
      #
      # @param [String] message
      # @param [Symbol, Array<Symbol>] id
      # @yield see #deprecate
      #
      def warn(message, id: [], &block)
        discard_or_log(:warn, message, id, &block)
      end

      #
      # Marks code as deprecated with/without replacement.
      #
      # @param [String] old
      # @param [String, nil] new
      # @param [Symbol, Array<Symbol>] id
      # @param [String] reference
      # @yield appends additional message to end of provided template
      #
      def deprecate(old, new = nil, id: [], reference: '', &block)
        id = Array(id)
        return if @ignored.include?(:deprecations)

        id << :deprecations if @allowed.include?(:deprecations)

        message = "[DEPRECATION] #{old} is deprecated"
        message << if new
                     ". Use #{new} instead."
                   else
                     ' and will be removed in a future release.'
                   end
        message << " See explanation for this deprecation: #{reference}." unless reference.empty?

        discard_or_log(:warn, message, id, &block)
      end

      private

      def create_logger(name, level:)
        logger = ::Logger.new($stderr)
        logger.progname = name
        logger.level = level
        logger.formatter = proc do |severity, time, progname, msg|
          "#{time.strftime('%F %T')} #{severity} #{progname} #{msg}\n".force_encoding('UTF-8')
        end

        logger
      end

      def discard_or_log(level, message, id)
        id = Array(id)
        return if @ignored.intersect?(id)
        return if @allowed.any? && !@allowed.intersect?(id)

        return if ::Logger::Severity.const_get(level.upcase) < @logger.level

        unless @first_warning
          @first_warning = true
          info("Details on how to use and modify Selenium logger:\n", id: [:logger_info]) do
            "https://selenium.dev/documentation/webdriver/troubleshooting/logging\n"
          end
        end

        msg = id.empty? ? message : "[#{id.map(&:inspect).join(', ')}] #{message} "
        msg += " #{yield}" if block_given?

        @logger.send(level) { msg }
      end
    end # Logger
  end # WebDriver
end # Selenium