‘You Gotta Have a Fiddler in the Band’

12.21.2011 08:18 by kbeckman | Comments

Due to popular request, I wanted to add a quick post with instructions on using Fiddler as a web proxy allowing you to capture all your browser traffic from Firefox on OSX (or any other platform for that matter). I posted a while back on how to setup a Windows SQL Server virtual machine using VirtualBox as the DB server for our Rails project. Now I’m going to take that a step further and put the VM to more good use. Anyone who has tried to run Wireshark to filter HTTP traffic will appreciate this…


Fiddler Setup

Unfortunately, Fiddler is a Windows-only installation and won’t run natively on OSX... So after installing it on your Windows VM, configure the following to allow remote connections. This will expose a service on port 8888 on the VM allowing you to setup a Firefox proxy on your host OS.




Firefox Setup on OSX

I like using Firefox over Chrome on OSX for capturing HTTP traffic because Firefox allows you to configure a proxy for browser traffic only. The Chrome configuration forces you to proxy your system’s network connection. It’s not a big deal, but if you proxy traffic from your network connection rather than just your browser, you might catch a lot of unwanted traffic from other connected applications. I guess it just depends where you want to do your filtering…


It’s a simple configuration in Firefox. Just go to the Advanced tab of your Firefox preferences and click the Settings button under the Connection section. Edit the Manual proxy configuration to point at your Fiddler service running on the Windows VM. A quick note here if you didn’t read my VirtualBox setup post. I have two network connections configured on the VM – a NAT network adapter for regular Internet traffic and a Host-Only adapter for database traffic, etc. The IP configured below in the Manual proxy configuration is the Host-Only adapter’s IP address.


Firefox1   Firefox2


And that’s it! Happy Fiddling!

Just a quick reminder to un-proxy your Firefox traffic when you’re done because the active Fiddler service is required. Your Internet connection will be disabled as soon as you shut down Fiddler if you don’t.

Issue: RubyMine Debugging (Debugger.Start is not called yet.)

10.11.2011 08:39 by kbeckman | Comments

Every once in a while, a little bit of collective thought during the “impediments” portion of the daily scrum yields some immediate results…



A portion of our development team uses RubyMine as the primary source code editor / IDE for Ruby development. Our team lead (the other guy) is more of a purist and boasts a status of VIM Power User never leaving the Terminal window. Recently, RubyMine’s debugging capabilities just stopped working on both of our active Rails projects. More specifically, every time we attempted to use RubyMine’s debugger to launch a single spec or cuke with breakpoints set, the entire test file failed. Even tests that should have passed failed to execute while everything worked perfectly from the command line. The stack trace revealed nothing more than a cryptic error like the one below. I shortened it a bit to include only the important items. Pay special attention to “RuntimeError: Debugger.start is not yet called.”

/Users/kbeckman/.rvm/rubies/ruby-1.9.2-p180/bin/ruby -e at_exit{sleep(1)};$stdout.sync=true;$stderr.sync=true;load($0=ARGV.shift) /Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/ruby-debug-ide-0.4.17.beta5/bin/rdebug-ide --port 49226 -- /Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/bin/rspec /Users/kbeckman/Sites/Project/spec/models/post_spec.rb --require teamcity/spec/runner/formatter/teamcity/formatter --format Spec::Runner::Formatter::TeamcityFormatter
Testing started at 10:20 PM ...
Fast Debugger (ruby-debug-ide 0.4.17.beta5, ruby-debug-base 0.11.28) listens on
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/ruby-debug-base19-0.11.24/lib/ruby_debug.bundle: warning: already initialized constant VERSION

RuntimeError: Debugger.start is not called yet.
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/ruby-debug19-0.11.6/cli/ruby-debug/processor.rb:130:in `breakpoints'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/ruby-debug19-0.11.6/cli/ruby-debug/processor.rb:130:in `at_breakpoint'
(eval):5:in `block in at_breakpoint'
<internal:prelude>:10:in `synchronize'
(eval):3:in `at_breakpoint'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/ruby-debug-base19-0.11.24/lib/ruby-debug-base.rb:42:in `at_breakpoint'
/Users/kbeckman/Sites/Project/spec/models/post_spec.rb:6:in `block (2 levels) in <top (required)>'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/hooks.rb:29:in `instance_eval'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/hooks.rb:29:in `run_in'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/hooks.rb:64:in `run_all!'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/hooks.rb:112:in `run_hook!'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/example_group.rb:176:in `eval_before_alls'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/example_group.rb:230:in `run'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/command_line.rb:27:in `block (2 levels) in run'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/command_line.rb:27:in `map'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/command_line.rb:27:in `block in run'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/reporter.rb:12:in `report'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/command_line.rb:24:in `run'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/runner.rb:55:in `run_in_process'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/runner.rb:46:in `run'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/rspec-core-2.3.1/lib/rspec/core/runner.rb:10:in `block in autorun'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/ruby-debug-ide-0.4.17.beta5/lib/ruby-debug-ide.rb:112:in `debug_load'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/ruby-debug-ide-0.4.17.beta5/lib/ruby-debug-ide.rb:112:in `debug_program'
/Users/kbeckman/.rvm/gems/ruby-1.9.2-p180@Project/gems/ruby-debug-ide-0.4.17.beta5/bin/rdebug-ide:87:in `<top (required)>'
-e:1:in `load'
-e:1:in `<main>'

2 examples, 2 failures, 0 passed

Finished in 0.002311 seconds

Process finished with exit code 0



Back to the “impediments” portion of the daily scrum… This issue was brought to everyone’s attention and we chatted about it for a couple of minutes. Since he wasn’t using RubyMine, our team lead was the only developer not having any issues with debugging. We soon discovered a few days ago he added a require statement for the ruby-debug gem in our RSpec spec_helper.rb file. Bingo!



It turns out that RubyMine automatically adds its own reference to the ruby-debug gem during its debugging process. With the new reference in our spec_helper.rb file, all RubyMine users had a dual reference (RubyMine’s version and to our project version in the RVM gemset). The runtime was unable to determine which gem version to use for debugging. With the issue discovered, the solution is easy. Adding a conditional statement in spec_helper.rb to ignore the ruby-debug reference (for RubyMine users only) solves the problem.


Step 1 – Set a Mac Environment Variable Indicating RubyMine Usage

Here’s a link to a System Preferences plug-in allowing you edit system environment variables via a GUI dialog. Or you can follow the steps in this post to manually edit your environment variables file. For documentation’s sake, here’s what my .MacOSX/environment.plist file looks like.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">


Step 2 – Update spec_helper.rb to Conditionally Add the ruby-debug Gem

require 'rubygems'
require 'spork'
require 'webmock/rspec'
unless ENV["USE_RUBYMINE"] == "TRUE"
  require 'ruby-debug'