I've got a wrapper for my Gem, socks, inside socks.rb. The entire file is made up of require statements, and a module declaration:
# lib/socks.rb
require 'socks/version'
require 'socks/base_controller'
require 'socks/templates'
require 'socks/tasks'
require 'socks/rake_tasks'
module Socks
end
However, require 'socks/tasks' and socks/rake_tasks is giving me a LoadError: no such file to load -- socks/tasks / rake_tasks error.
Is this a problem with the alignment of the require statements, or just the code?
Code is on Github: https://github.com/Beakr/socks
EDIT: require './socks/tasks' is now working, however require './socks/rake_tasks' is not.
Ruby load files using its $LOAD_PATH. This global array is changed by e.g. rubygems and bundler to allow to find libraries in various locations. In your sock.gemspec you have defined
gem.require_paths = ["lib"]
which means that rubygems will add the lib directory of your gem to ruby's $LOAD_PATH. But it odes so only if you have installed the gem and the gemspec is thus evaluated. If you don't want to install your gem, you can test your gem using
bundle exec irb
in your gem directory, or alternatively by first adapting your $LOAD_PATH in your irb session like so:
$LOAD_PATH.push "/path/to/your/gem/lib"
require 'socks'
Related
This is in my Gemfile:
gem "trinsic_service_clients", "~> 1.1"
This is at the top of my file named instantiate_clients.rb
require_relative 'trinsic_service_clients
However, when I run bundle exec ruby instantiate_clients.rb I still get this error:
Traceback (most recent call last):
1: from instantiate_clients.rb:1:in `<main>'
instantiate_clients.rb:1:in `require_relative': cannot load such file -- /home/runner/DefenselessGrowlingExtraction/trinsic_service_clients (LoadError)
When I type bundler exec gem which trinsic_service_clients I get the following:
/home/runner/DefenselessGrowlingExtraction/.bundle/ruby/2.5.0/gems/trinsic_service_clients-1.1.5018/lib/trinsic_service_clients.rb
require_relative is for code in your application. It is not for code stored in gems. For those you should use require as it will look through $LOAD_PATH for the required files.
The easy way to make use of Gemfile is to load everything in via one shot:
require 'bundler'
Bundler.require(:default)
This not only adds the gem declarations, but does default require calls as well, as in this should already require your declared gem.
There's also require 'bundler/setup' which only adds the load paths, you still need to require, but this can help minimize load times if you may not necessarily need all the gems.
require 'bundler/setup'
require 'trinsic_service_clients'
This can be useful if your Gemfile has a lot of dependencies, but the scripts you're running may only use a small subset of them.
I can't require third party code in my .gemspec file. I would like to require a semver library to manage my version number. Why can't I require gems inside my .gemspec?
I have a workaround for my particular problem. What I am interested in the specific reason I can't require code from inside a gemspec. I feel like I am missing something about how Rubygems work. Thanks!
lib = File.expand_path('../lib', __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
require 'semver'
Gem::Specification.new do |spec|
spec.add_dependency "semver2", "~> 3.4.2"
spec.version = SemVer.find.to_s[1..-1]
end
Running bundle install results in the following error:
$ bundle
[!] There was an error parsing `Gemfile`: There was a LoadError while loading example.gemspec:
cannot load such file -- semver from
/opt/pose/auto/stack-overflow/example/example.gemspec:3:in `<main>'
Obviously there is some point before which you cannot depend on 3rd party gems to be on your LOAD_PATH. I am asking for an explanation of where that point is. My guess is because my Gemfile references my gemspec and Bundler had not loaded all the dependencies yet, but that is a guess.
A .gemspec is just a Ruby script like any other Ruby script. Basically the only thing that is "special" is that it is run in an environment where certain libraries have already been required, such as rubygems/specification.
requireing libraries works just like in any other Ruby script.
I use:
rvm 1.25.19 (stable)
ruby 1.9.3p545
I install gem rake command
gem install rake
I understand that $LOAD_PATH should contain the paths:
~/.rvm/rubies/ruby1.9/gems/rake/lib
~/.rvm/rubies/ruby1.9/gems/rake/bin
I execute command:
ruby -e 'puts $LOAD_PATH'
output:
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/site_ruby/1.9.1
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/site_ruby/1.9.1/x86_64-linux
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/site_ruby
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/vendor_ruby/1.9.1
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/vendor_ruby/1.9.1/x86_64-linux
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/vendor_ruby
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/1.9.1
/home/slip/.rvm/rubies/ruby-1.9.3-p545/lib/ruby/1.9.1/x86_64-linux
why path to gem 'rake' don't add?
Installing a gem in Ruby doesn’t automatically add that gem’s files to the load path. When you require a file, first the existing load path is searched and if no matching file is found then Rubygems searches the installed gems for the file. If such a gem is found, then it is activated, which is when the gem’s lib directory is added to the load path.
Here’s an example using the Haml gem:
puts "Before:"
puts $LOAD_PATH
puts
require 'haml'
puts "After:"
puts $LOAD_PATH
This produces:
Before:
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby/1.9.1/x86_64-darwin10.8.0
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby/1.9.1/x86_64-darwin10.8.0
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/x86_64-darwin10.8.0
After:
/Users/matt/.rvm/gems/ruby-1.9.3-p448/gems/tilt-1.4.1/lib
/Users/matt/.rvm/gems/ruby-1.9.3-p448/gems/haml-4.0.5/lib
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby/1.9.1/x86_64-darwin10.8.0
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/site_ruby
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby/1.9.1/x86_64-darwin10.8.0
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/vendor_ruby
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1
/Users/matt/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/x86_64-darwin10.8.0
See how the lib directories for Tilt (which is a dependency of Haml) and Haml have been added to the start of the load path.
In the case of some gems, such as Rake, this is complicated by the fact they are part of the standard library and so are already on the load path. If you changed the example above to use require 'rake' then you wouldn’t see any change in the load path. In this situation you can specify you want to use the gem version with the gem method. This activates the gem in question, placing its lib directory at the start of the load path so when you later call require you will load the correct version.
For example, this script
require 'rake'
puts Rake::VERSION
produces 0.9.2.2 with Ruby 1.9.3, as that is the version of Rake included in the standard library. However this script:
gem 'rake'
require 'rake'
puts Rake::VERSION
produces 10.1.1, since that is the current highest version of the Rake gem installed on my system. You can also specify a particular gem version by providing a second argument to gem (this is the same syntax as used in Gemfiles). Note that the gem method doesn’t require any files, you have to do that as a separate step.
I'm trying to use rake in my ruby script...(Ruby 1.8.6, JRuby 1.6.5)
Downloaded rake using gem install --remote rake, looks ok on install...
Fetching: rake-0.9.2.2.gem (100%)
Successfully installed rake-0.9.2.2
1 gem installed
I've got a simple ruby script which works fine, but when I import rake to using any of the following requires, it starts complaining....
require 'rake'
LoadError: no such file to load -- rake
or
require '/lib/rake'
LoadError: no such file to load -- lib/rake
After some searching, I found that adding require 'rubygems' just before rakefixes the issue....
require 'rubygems'
require 'rake'
Even though it's working, I've got some questions...
The gem spec on rake shows the require_path as lib, so why
doesn't require '/lib/rake' work? Am I misunderstanding the significance of require_path?
Why is it necessary to place require 'rubygems' before require
'rake'
Yes, you are misunderstanding the significance. The require_paths in the specification is an array of subdirectories of that gem's installation directory that should be searched for files belonging to the gem.
To find out where rake really is, try this:
$ gem which rake
You'll see that it is actually installed somewhere completely unrelated to /lib; on my system, it's under /var/lib/gems. Ruby gems, in general, live in their own directory structure; the only file in the standard Ruby include path ($:) is rubygems itself, which you used to have to explicitly require in order to make any actual gems visible. (Since Ruby 1.9, that has not been necessary.)
Gems are more complex than just libraries to load; you can have multiple versions of the same gem installed, and specify which one you want at a time, and do other things that wouldn't work if the gems were just dumped into the standard Ruby include path.
The require_path in the gemspec tells ruby where the files of this gem are located within the gem. It makes you able to type require 'rake', and ruby then knows it needs to look for /lib/rake within the gem installation folder.
In Ruby 1.8, rubygems (the mechanism responsible for making gems available to your app) is not loaded by default, and the default ruby isn't aware of any gem on your system. You need to load rubygems before being able to require any other gem. This is not the case anymore with Ruby 1.9.
I'd like to use bundler/setup to include all of my listed gems but I'm not
succeeding. In go.rb I have
require 'rubygems'
ENV['BUNDLE_GEMFILE'] ||= File.expand_path('Gemfile', __FILE__)
require 'bundler/setup' if File.exists?(ENV['BUNDLE_GEMFILE'])
which fails to require httparty as I thought it would:
$ bundle exec ruby go.rb
go.rb:5:in `<main>': uninitialized constant HTTParty (NameError)
What am I doing incorrectly?
I've created a small project for this question, here.
As far as I understand 'bundler/setup' it only manages the require path (removes the default contents and adds paths for gems that are defined in Gemfile.lock). If you don't require the libraries in question, their contents won't be available.
I believe the problem in your particular case is the following snippet:
File.expand_path('Gemfile', __FILE__)
If I run this from a file called /foo/bin/somescript, what the above code expands to is /foo/bin/somescript/Gemfile. Presumably what you actually want is /foo/bin/Gemfile, which you can get with:
File.expand_path('../Gemfile', __FILE__)
So, repeating your original code with the correction:
require 'rubygems'
ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __FILE__)
require 'bundler/setup' if File.exists?(ENV['BUNDLE_GEMFILE'])
This seems to work for me, to have files in my ~/bin directory have access to libraries I've installed by running bundle install within that directory, as specified by the Gemfile therein.