easy-going-rails/lib/formatters/basic_formatter.rb

# Opinioned Rails custom formatter
class BasicFormatter < SemanticLogger::Formatters::Color
  NAME_MAX_SIZE = 25

  ANSI_DEBUG = "\e[90m".freeze
  ANSI_INFO = SemanticLogger::AnsiColors::GREEN
  ANSI_WARN = SemanticLogger::AnsiColors::YELLOW
  ANSI_ERROR = SemanticLogger::AnsiColors::RED
  ANSI_FATAL = SemanticLogger::AnsiColors::MAGENTA
  ANSI_NEUTRAL_INFO = SemanticLogger::AnsiColors::WHITE
  ANSI_REVERSED_WARNING = "\e[0;30;43m".freeze
  ANSI_REVERSED_ERROR = "\e[1;30;41m".freeze
  ANSI_REVERSED_FATAL = "\e[1;30;41m".freeze

  CONTENT_COLOR_MAP = ColorMap.new(
    debug: ANSI_DEBUG,
    info: ANSI_NEUTRAL_INFO,
    warn: ANSI_REVERSED_WARNING,
    error: ANSI_REVERSED_ERROR,
    fatal: ANSI_REVERSED_FATAL
  )

  def initialize
    super(color_map: ColorMap.new(
      debug: ANSI_DEBUG,
      info: ANSI_INFO,
      warn: ANSI_WARN,
      error: ANSI_ERROR,
      fatal: ANSI_ERROR
    ))
  end

  def message
    return unless log.message

    "  #{CONTENT_COLOR_MAP[log.level]}#{log.message}#{color_map.clear}"
  end

  def level
    level = log.level == :info ? ' ' : log.level.to_s.chr.upcase
    "#{color}╣#{level}╠#{color_map.clear}"
  end

  def name
    "#{ANSI_DEBUG}#{log.name.truncate(NAME_MAX_SIZE).center(NAME_MAX_SIZE)}#{color_map.clear}"
  end

  def exception
    return unless log.exception

    root_path = Rails.root.to_s
    backtrace = log.exception.backtrace.select { |line| line.starts_with?(root_path) }
    if backtrace.count.positive?
      "-- #{ANSI_REVERSED_ERROR}#{log.exception.class}#{color_map.clear} #{color}#{log.exception.message}\n#{color} ↳ #{backtrace.join("\n ↳ ")}#{color_map.clear}\n\n"
    else
      "-- #{ANSI_REVERSED_ERROR}#{log.exception.class}: #{log.exception.message}#{color_map.clear}\n\n"
    end
  end

  def call(log, logger)
    self.color = color_map[log.level]
    self.log = log
    self.logger = logger

    [name, level, tags, named_tags, duration, message, payload, exception].compact.join(' ')
  end
end