sinatra logger template.rb

require 'sinatra/base'
require 'logger'

module Sinatra

  class CustomFormatMiddleware

    FORMAT = %{%s - %s [%s] "%s %s%s %s" %d %s %0.4f\n}

    def initialize(app, logger)
      @app, @logger = app, logger
    end


    def call(env)
      began_at = Time.now

      status, header, body = @app.call(env)
      header = Rack::Utils::HeaderHash.new(header)
      body = Rack::BodyProxy.new(body) { log(env, status, header, began_at) }
      [status, header, body]
    end

    private

    def log(env, status, header, began_at)
      now = Time.now
      length = extract_content_length(header)

      msg = FORMAT % [
        now.strftime("%Y-%m-%d %H:%M:%S.%L") + " INFO:",
        env['HTTP_X_FORWARDED_FOR'] || env["REMOTE_ADDR"] || "-",
        env["REMOTE_USER"] || "-",
        env['REQUEST_METHOD'],
        env['PATH_INFO'],
        env['QUERY_STRING'].empty? ? "" : "?"+env['QUERY_STRING'],
        env["HTTP_VERSION"],
        status.to_s[0..3],
        length,
        now - began_at ]

      logger = @logger || env['rack.errors']
      # Standard library logger doesn't support write but it supports << which actually
      # calls to write on the log device without formatting
      if logger.respond_to?(:write)
        logger.write(msg)
      else
        logger << msg
      end
    end

    def extract_content_length(headers)
      value = headers['Content-Length'] or return '-'
      value.to_s == '0' ? '-' : value
    end
  end

  module CustomFormat

    def self.registered(app)

      app.use Sinatra::CustomFormatMiddleware, Logger.new(STDOUT)

      ::Sinatra::Base.class_eval do
        def dump_errors!(boom)
          msg = ["#{Time.now.strftime("%Y-%m-%d %H:%M:%S.%L")} FATAL: #{boom.class} - #{boom.message}:", *boom.backtrace].join("\n\t")
          @env['rack.errors'].puts(msg)
        end
      end

    end #/ self.registered
  end

  register(Sinatra::CustomFormat)

end