I have a project using cucumber outside of rails. How can I load the gems with the versions specified in my gemfile?
Digging through the Bundler website:
Create Gemfile (run bundle init to create skeleton Gemfile)
bundle install
In your app:
# Only needed for ruby 1.8.x
require 'rubygems'
# The part that activates bundler in your app
require 'bundler/setup'
# require your gems as usual
require 'some_gem'
# ...or require all the gems in one statement
Bundler.require
Could be worth checking out:
Bundler.io - Using Bundler in Your Appplication
Bundler.io - Bundler.setup and Bundler.require
Are bundle exec and require 'bundler/setup' equivalent?
I just learned about a way to make Bundler automatically require dependencies from a Gemfile. Add this code at the beginning of a Ruby program that has a Gemfile:
require 'rubygems'
require 'bundler/setup'
Bundler.require
With Bundler.require there's no need to explicitly require the gems/libraries enumerated in the Gemfile.
This solution is from http://technotales.wordpress.com/2010/08/22/bundler-without-rails/
To be honest I'm not sure if the require rubygems part is needed either.
Here's the simplest and most straightforward approach:
bundler init will create the Gemfile for you
Specify gems in the Gemfile.
Add the following to your main Ruby file
require 'bundler/setup'
Bundler.require
Run bundler install to install the gems.
More information can (now) be found at http://bundler.io.
Casper has a pretty good answer (despite some passive aggressiveness) but I think the missing piece for you is bundle exec. When you run the $ rails ... commands on the command line, Rails uses bundler to load those dependencies/gems. Rake, for example, doesn't by default so in order to run rake test using an older version of cucumber than what is on your system, you have to use bundle exec rake test. It's a good habit to get into always using $ bundle exec ... when you're using Bundler — it's explicit, you're always sure you're using the right gems, and it ensures you don't forget to add a dependency to your Gemfile (i.e. you push to another server or another developer and they are having issues because you didn't note the need for something you use but they don't).
Related
I have a script that needs to require specific files out of gems defined in the project Gemfile.
#!/usr/bin/env ruby
require 'some_gem/helpers/some_helper'
... rest of script
When I run the script, I get an error about not being able to load some_helper.rb. If I run with bundle exec command... then everything works.
I understand that bundle exec exposes the Gems to the $LOAD_PATH which lets require work. Is there a way to move that capability into the script so users don't have to type bundle exec?
Do I just need to add require "bundler/setup" to the script before I require the gem files?
http://bundler.io/v1.12/#getting-started
:)
#!/usr/bin/env ruby
require 'rubygems' # because reasons.. most probably it is not needed unless you are using really old ruby where it is not loaded by default
# also at the moment rubygems and bundler are being merged :)
require 'bundler/setup' # for things installed with bundler
require 'some_gem/helpers/some_helper'
You can also check e.g. http://mislav.net/2013/01/understanding-binstubs/
I noticed for some gems you must include it in the file where you want to use it like this require 'a_gem', but this is not always the case.
I am going to compose a gem by myself. What should I do if I do not want to add the require 'my_gem' to the .rb file when using it?
Usually, an application that is using a gem needs to require the gem:
require "my_awesome_gem"
MyAwesomeGem.do_something_great
However, if an application is using bundler, which defines the application's gem in a file called "Gemfile":
source 'http://rubygems.org'
gem 'my_awesome_gem'
then the application may invoke bundler in a way that automatically requires all of the gems specified in the Gemfile:
require "bundler"
Bundler.require
MyAwesomeGem.do_something_great
Rails projects use Bundler.require, so a Rails application will not need to explicitly require a gem in order to use it: Just add the gem to the Gemfile and go.
For more about Bundler.require, see the bundler documentation
For more about how Rails uses Bundler, see How Does Rails Handle Gems? by Justin Weiss.
This doesn't make sense. If you want to write a Gem and use it, it needs to be required somewhere.
This "somewhere" could be explicit in one of your scripts, it could be written in a Gemfile or it could be required by another script/gem that is required by your script.
If you write a gem, Ruby will not include it automatically in all your scripts.
Finally, if you publish it, should every single Ruby script on earth magically require it and execute your code?
I suppose that the project you have seen which didn't use require 'a_gem' was using a Gemfile.
I'm writing a batch script as a setup for a ruby program I'm writing. It needs to be able to
a. Make sure Ruby is installed on the user's computer (and if not point them to the ruby download page)
b. make sure the ruby "yaml" gem is installed, which is a prerequisite for it. I've tried
gem install yaml
in the batch script to no avail. How can I write a batch script that will do these two things?
As far as I know, there is no yaml gem. Although it must be required in code that uses it, it is distributed as part of a Ruby installation. Try this:
ruby -ryaml -e"puts 'YAML found'"
It should work; and if you change the -r token to some nonexistent gem, you'll see an exception raised.
Instead of writing your own script, you could use bundler and create a gemfile. This way people can install all the gems on any operating system.
Example:
require 'rubygems'
require 'bundler/setup'
require 'nokogiri'
require 'rest-client'
#require all your gems like normal
def parse(site)
Nokogiri::HTML(RestClient.get(site))
end
And for the gem file:
source: "https://rubygems.org"
gem 'nokogiri', '~> 1.6.7.2' #<= you can specify which version
gem 'rest-client' #<= you don't have to specify a version though
After you've got everything set up, cd to the directory that has the gemfile and run bundle install this will install all the gems
So, I've created a GitHub to manage my latest Ruby project, and I want for it to utilize a couple of gems. On my PC, all I have to go is type
gem install "gemName"
and it loads it to my computer, and then all I have to do in my Ruby script is have
require "rubygems"
require "gemName"
How can I do this with GitHub? What I tried to do is create a subfolder from the main repository (called "RubyGems") and then in my main ruby script
require "/RubyGems/colorize"
require "/Rubygems/psych"
With the two gems (colorize and psych) in the "RubyGems" folder.
Is this the proper way to do this? Will this even work? What is the right way to do this? (Sorry, I'm kinda new to GitHub.)
A couple of things, unless you're using a really old version of Ruby (like 1.9) you don't need to require 'rubygems' because is already required by default, next I highly recommend you to get familiar with bundler.
Bundler is used for "bundling" the required gems you use, to so do you have to install the gem (gem install bundler) and then you create a Gemfile, like this:
source 'https://rubygems.org'
ruby '2.2.0'
gem 'colorize', git: 'https://github.com/fazibear/colorize.git'
gem 'psych'
Execute bundle install after, that will create Gemfile.lock file, make sure you push both files to your repository.
With that you would be able to bundle exec ./your-script.rb, assuming your script is something like this:
require 'psych'
require 'colorize'
# Here I do stuff with psych and colorize
I have a private gem (built with jeweler) hosted on Github. I run unit tests before I commit but I'd like to test everything works when I use bundler from the end-user side.
So far I've just been creating a test environment with two files:
Gemfile:
gem 'my_gem', :git => 'git#github.com:my_repo/my_gem.git'
main.rb:
require "rubygems"
require "bundler/setup"
require "my_gem"
# Some code calling arbitrary methods from my gem
It seems like there's probably a way for me to run the unit tests built in to the gem.
Bundler supports the use of gemspecs for development. You can change your gemfile to the following:
source "http://www.rubygems.org"
gemspec
This will allow you to access all the gems you would need as a client of the gem you're building. Then in your test file you can just:
require "my_gem"
You can find more information in Yehuda's post.