Nice colorized logs for Rails apps! With this initializer, you can instantly colorize your Rails development logs. Just copy and paste the code, and it’ll work. https://x.com/kyrylosilin/status/1852308566201237815

colorized_logger.rb

# frozen_string_literal: true
# config/initializers/colorized_logger.rb

# This initializer adds color to the Rails logger output. It's a nice way to
# visually distinguish log levels.
module ColorizedLogger
  COLOR_CODES = {
    debug:   "\e[36m",  # Cyan
    info:    "\e[32m",  # Green
    warn:    "\e[33m",  # Yellow
    error:   "\e[31m",  # Red
    fatal:   "\e[35m",  # Magenta
    unknown: "\e[37m"   # White (or terminal default)
  }.freeze

  RESET = "\e[0m"

  def debug(progname = nil, &block)
    super(colorize(:debug, progname, &block))
  end

  def info(progname = nil, &block)
    super(colorize(:info, progname, &block))
  end

  def warn(progname = nil, &block)
    super(colorize(:warn, progname, &block))
  end

  def error(progname = nil, &block)
    super(colorize(:error, progname, &block))
  end

  def fatal(progname = nil, &block)
    super(colorize(:fatal, progname, &block))
  end

  def unknown(progname = nil, &block)
    super(colorize(:unknown, progname, &block))
  end

  private

  def colorize(level, message, &block)
    "#{COLOR_CODES[level]}#{message || (block && block.call)}#{RESET}"
  end
end

Rails.logger.extend(ColorizedLogger)

Thanks for the tip, i changed it a bit, but remains the same in terms of features.

# frozen_string_literal: true
module ColorizedLogger
  RESET = "\e[0m"
  COLOR_CODES = {
    unknown: RESET, # Terminal default
    debug: "\e[0;36m", # Cyan text
    info: "\e[0;32m", # Green text
    warn: "\e[1;33m", # Yellow text
    error: "\e[1;31m", # Red text
    fatal: "\e[1;31m", # Bold Red text
  }.freeze
  %i[debug info warn error fatal unknown].each do |level|
    define_method(level) { |progname = nil, &block| super(colorize_message(level, progname || (block && block.call))) }
  end
  private
  def colorize_message(level, message)
    "#{COLOR_CODES[level]}#{message}#{RESET}"
  end
end
Rails.logger.extend(ColorizedLogger)

@navidemad If you like code golfing, here's an even shorter version:

# frozen_string_literal: true
module ColorizedLogger
  %i[debug info warn error fatal unknown].each do |level|
    color = case level
            when :debug then "\e[0;36m"  # Cyan text
            when :info  then "\e[0;32m"  # Green text
            when :warn  then "\e[1;33m"  # Yellow text
            when :error, :fatal then "\e[1;31m"  # Red text
            else "\e[0m"  # Terminal default
            end
    
    define_method(level) do |progname = nil, &block| 
      super(color + (progname || (block && block.call)).to_s + "\e[0m")
    end
  end
end
Rails.logger.extend(ColorizedLogger)