Pry

Pry tricks

binding.pry in external code

Simply monkey patch the method that you are interested in debugging:

def SomeGem::method
  require 'pry'
  binding.pry
  super
end

You can even do this automatically for a list of methods you are interested in:

[:foo, :bar, :baz].each do |cb|
  define_method cb do
    require 'pry'
    binding.pry
    super
  end
end

Get filtered stack trace

# at breakpoint
caller.select {|line| line.starts_with? '/your-app-dir' }