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Igor Kasyanchuk
Igor Kasyanchuk

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How to know always about how fast is your code in Rails console?

#rails #console #ror #performance

First, please check this demo of my gem below:

Alt Text

and the link to the gem: https://github.com/igorkasyanchuk/execution_time

It's basically checking total execution time, Active Record spent time and Allocations. Very similar to what you see in logs during regular RoR requests in the logs.

So, no more code like

t0 = Time.now # code puts Time.now - t0
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This gems works with both IRB and Pry consoles.

The 99% of code is located in one file, and you can see a good example of usage "prepend" method.

module ExecutionTime class AppMetrics @@counter = 0 cattr_reader :counter def self.reset @@counter = 0 end def call(event_name, started, finished, event_id, payload) @@counter += 1 end # def red; colorize(self, "\e[1m\e[31m"); end # def green; colorize(self, "\e[1m\e[32m"); end # def dark_green; colorize(self, "\e[32m"); end # def yellow; colorize(self, "\e[1m\e[33m"); end # def blue; colorize(self, "\e[1m\e[34m"); end # def dark_blue; colorize(self, "\e[34m"); end # def colorize(text, color_code) "#{color_code}#{text}\e[0m" end def AppMetrics.with_color(text) "\e[1m\e[32m[METRICS]\e[0m \e[32m#{text}\e[0m" end end ActiveSupport::Notifications.subscribe( "sql.active_record", ExecutionTime::AppMetrics.new ) class Measurer def Measurer.watch AppMetrics.reset start = Time.now before = GC.stat(:total_allocated_objects) ActiveRecord::LogSubscriber.reset_runtime result = yield after = GC.stat(:total_allocated_objects) duration = (Time.now - start) db_after = ActiveRecord::LogSubscriber.reset_runtime info = "Completed in #{(duration * 1000).round(1)}ms | Allocations: #{after - before}" if AppMetrics.counter > 0 info << " | ActiveRecord: #{db_after.round(1)}ms" info << " (queries: #{AppMetrics.counter})" end puts AppMetrics.with_color(info) result end end module IrbContextExt def evaluate(*args) Measurer.watch do super(*args) end end end module BindingExt def eval(*args) if args == ['self'] || args == [''] super(*args) else Measurer.watch do super(*args) end end end end module PryExt def evaluate_ruby(code) current_binding.class.send :prepend, BindingExt super(code) end end end
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Code above could also tell you more about:

  • blocks
  • "inheritence" using prepend and super
  • passing unknown arguments further using *args
  • Rails ActiveSupport::Notifications (internal) + subscription
  • simple usage of GC stats (code examples I took from Rails sources)
  • colorized string output :)

PS: Gem was created maybe in 1.5 hour, and most of the time I spent on inspecting source code of Rails and Pry gems. But it shows that even in a such short amount of time it's possible to create useful tools.

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