#54 Debugging Ruby (revised)

Apr 07, 2012 | 7 minutes | Debugging, Tools

This episode will show you how to debug a rails app using the "debugger" gem: set a breakpoint, inspect variables and change the executed code at runtime.

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Dominik Menke over 12 years ago

Nice-to-know episode! Any idea, why ruby-debug19 was abandoned?

—Dominik

Aditya Sanghi over 12 years ago

@dominik it's not really abandoned, it's just not being looked after as it should be. It's a huge pain to install on Ruby 1.9.3 due to gems not released to rubygems.org! Personally I think it was about time it was forked considering 1.8.7's death is preeminent and 1.9.3 has been GA for over 6 months.

Dominik Menke over 12 years ago

That qualifies for »abandoned«, in my opinion ;-)

I had have also trouble to install ruby-debug19 on some Debian machines with Ruby 1.9.2 using either RVM or rbenv. debugger works like a charm :-)

cmar over 12 years ago

Any tips for using debugger or pry with Pow?

Xavier Lozinguez over 12 years ago

you can use pry-remote: https://github.com/Mon-Ouie/pry-remote

Ali Anwar over 12 years ago

Hi, I'm using pry and pry_debug in my rails application, have no problem at all with "rails console",but I can't figure out how to step when I include binding.pry in my controller. any hints please.

Thanks!

Ali Anwar over 12 years ago

I found out about
pry-nav

adding this to Gemfile:
gem 'pry'
gem 'pry-rails'
gem 'pry-remote'
gem 'pry-nav'

Mike Goggin over 12 years ago

As always, good information. I use pry on a daily basis in both Rails and POR apps. Great tool for effective debugging.

WU Jun over 12 years ago

Timezone is not easy as it looks. Timezone-related code must be carefully written.

I tried to find an easy way to set Rails config.time_zone to local but failed.

Now I use an initializer:

          ruby
        
# from rake task time:zones:local
jan_offset = Time.now.beginning_of_year.utc_offset
jul_offset = Time.now.beginning_of_year.change(:month => 7).utc_offset
offset = jan_offset < jul_offset ? jan_offset : jul_offset

offset = if offset.to_s.match(/(\+|-)?(\d+):(\d+)/)
           sign = $1 == '-' ? -1 : 1
           hours, minutes = $2.to_f, $3.to_f
           ((hours * 3600) + (minutes.to_f * 60)) * sign
         elsif offset.to_f.abs <= 13
           offset.to_f * 3600
         else
           offset.to_f
         end

ActiveSupport::TimeZone.all.each do |zone|
  if offset.nil? || offset == zone.utc_offset
    # use that timezone
    Rails.application.config.time_zone = zone.name
    break
  end
end

Tyler Smart over 12 years ago

I switched to RubyMine from VIM a while ago b/c the remote degugger is such a pain to inject every time using VIM/TEXTMATE/WHATEVER. Visual debugging is REALLY nice :) I'm not sure what technique they use, but debugging has worked on Ruby 1.9.3 for a while with RubyMine.

Sam Granieri over 12 years ago

THere is a a way to get ruby-debug working on ruby 1.9.3
put this in your gemfile

          ruby
        
source 'http://rubydebug19.s3.amazonaws.com'
gem 'ruby-debug19', :group => :development

I found this at Stackoverflow

Sergey Kuleshov over 12 years ago

I know it is rather controversial but I found RubyMine IDE to be a great way to debug rails apps. It has very cool UI for debugger with breakpoints, visual stack and so forth.

Aditya Sanghi over 12 years ago

If I can get some attention or upvotes, you'll help stamp out ruby-debug19 from the Rails Gemfile template https://github.com/rails/rails/pull/5835

Marco Brinkmeier over 11 years ago

debugger don't work properly with ruby 2.0. Try this https://github.com/deivid-rodriguez/byebug. It's almost the same. But it don't work with ruby 1.9.x. For ruby 1.9.3 works debugger fine.