Creating a Ruby gem // 'require' error: cannot load such file (LoadError)

Question

I am trying to create my first Ruby gem and I get a LoadError on the first 'require' line.

Inside my gem folder I have 3 classes including 'version.rb' (where the LoadError is occurring)

version.rb

module OptimalBankroll
 VERSION = "0.0.1"
end

numeric.rb ( i modify the numeric class so that any integer/float used will be changed to a percentage:

module OptimalBankroll
 class Numeric
  def to_percentage
    self.to_f / 100
  end
 end
end

bet_size.rb ( Ex: BetSize.new.amount(1000,1), returns ==> 10

module OptimalBankroll
 class BetSize
  def amount(bankroll, unit)
   bankroll.round(2) * unit.round(2).to_percentage
  end
 end
end

optimal_bankroll.rb ( here is where I get the LoadError )

require "optimal_bankroll/version"
require "optimal_bankroll/numeric"
require "optimal_bankroll/bet_size"

module OptimalBankroll

end

p OptimalBankroll::BetSize.new.amount(1000, 0.5)

rubygems/core_ext/kernel_require.rb:53:in `require': cannotload such file --
optimal_bankroll/version (LoadError)

I am completely green with creating Ruby gems so any advice would be helpful, thanks!

Answer 1

If the string you pass into require is not an absolute path, it will only check for the file in directories specified in $LOAD_PATH . Normally, these files are placed in lib/ , which is added to $LOAD_PATH in your gemspec. Make sure you have these lines in your gemspec:

lib = File.expand_path('../lib', __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)

So then for your require to work you would need to use this folder structure:

/
└── lib/
   └── optimal_bankroll.rb
   └── optimal_bankroll/
      └── version.rb
      └── numeric.rb
      └── bet_size.rb

It is standard practice to use the directory scheme described above, and changing $LOAD_PATH to match where you've placed your files rather than vice versa should be avoided.

Here is a guide on how to create a gem with bundler. You may find it helpful if you're just getting started with gem development. http://bundler.io/v1.6/rubygems.html