How to distribute a Ruby application with the required gems - ruby

I've developed a Ruby application (a small game), and I would like to 'distribute' it to other people.
However, I am not sure what to do about the required gems. If I just send my application to someone who have ruby installed, but not the required gems, I assume it will blow up. Can I package the gems locally? If so, would it conflict if the other person has a different version of the gem?
So, what is the smart/proper/good way of doing this?

The best way would probably be to just package your game as a gem as well, that way rubygems will take care of installing the dependencies. Here's the documentation explaining how to create your own gems.

If you'd rather not package your game as a gem, you could investigate the Bundler, which will be integrated into Rails 3.

In your environment.rb you can express your gem dependencies, eg.
config.gem "activemerchant", :lib => "active_merchant", :version => "1.4.1"
This isn't as automatic as gem dependencies, but it certainly usable. User must sudo rake gems:install to get your app to start.

If you're looking for a way to create OSX .dmg's and Windows Installers, there's a gem called releasy that will do all of that for you, and it is specifically tailored for releasing GUI apps written in Ruby. It bundles up Ruby and all your gem dependencies in to a single executable so that your end user doesn't have to install anything extra.
You will need access to a Windows/OSX environment to make the installers.

Related

Ruby beginner - using /modifying existing gems in single project

As the title states, I'm a beginner in Ruby.
My project uses 2 existing gems - which I want to modify.
I've forked the gems on GitHub and put them as modules in my repo and they show up as a subdirectory.
I've tried researching this, but I keep on getting lost - I'm thinking I'm missing some basic concepts/knowledge here.
My questions:
Am I going about this right/wrong?
Is it even possible to include the code of those (forked) gems in my actual project, or should I update them separately and just use them as actual gems with require (this seems very cumbersome)
If these gems are part of my project, how do I use them properly, I assume I don't need the require piece? If not, how do I access/use them?
Thanks!
BTW, using Ruby 1.9.2-p194 on Ubuntu with RubyMine as the IDE.
Probably wrong. Ruby is a very flexible language, and has what are called open classes. This means that you can open up and change classes at run-time. Doing this on an external library is called monkey patching. So instead of having to replicate all of the code you want to stay consistent, you can just modify the classes and override any methods you want.
A simple example:
class Fixnum
def is_multiple_of_three?
self % 3 == 0
end
end
However, if the changes you want are really significant, it could make sense to fork the gem.
I recommend the bundler gem. This will let you make a Gemfile which lists all of your dependencies. You can list a github repository as a source for the gem, like so:
gem 'gem_name_here', :git => 'git://github.com/username_here/gem_name_here.git'
and then run bundle install to install your dependencies.
If you install the gems with bundler, it acts just like any other gem you have installed.

How can I install a gem as if it was specified in a Gemfile?

I want to install a gem via gem install, but I need it to resolve with dependencies of the current project.
Basically I want the functionality that bundler gives me when I specify gem 'xyz' in a Gemfile, but I don't want to add that specific gem into the Gemfile.
I tried doing bundle exec gem install ... but it doesn't seem to work.
edit: The reason why I don't want to add it to the Gemfile is that it might be something like metric_fu, metrical, saikuro, rails_best_practices, etc. Simply gems that are kind of utility use and might only cluttler the project.
I might only want to use them temporarily, or install them, try out, if it doesn't work out the way I want do rvm gemset empty and bundle install again to clean up.
The point of Bundler is, in part, to prevent you from doing things like that (to prevent you from injecting gems from outside when your project doesn't declare them).
Looking for a way of doing that is looking for a bug in Bundler. If you did manage to find some way of skirting Bundler's enforcement mechanisms, you should probably not use it; instead, you may consider filing it as a bug with Bundler's issue tracker.
Now we come to the real questions: what can you do? and what should you do?
You should use either RVM gemsets or Bundler to isolate your application and its gem dependencies. You don't need both. I would recommend Bundler for this purpose over RVM gemsets.
You should add to your Gemfile any gems that you want to use and that integrate with your application (i.e., that either load your application or that are loaded as part of your application). This is not a requirement for any gems that refrain from integrating with your application.
You should refrain from committing a changed Gemfile or Gemfile.lock to version control until you are satisfied that your application continues to operate acceptably (tests pass, new gem does something useful, etc.).
Or you should stop using Bundler, because you want to do things it is explicitly designed to prevent you from doing (not recommended).
At the risk of sounding dumb, why not add it to the gemfile? You can always add it to its own group if you don't want to have to install it everywhere.
A slightly different approach is, if you're using version control, such as Git, to create a new branch and install the gems. If it doesn't work out, uninstall the gem (I'm not sure this will be done by bundle update on the old branch) and trash the branch. If it does, work, merge your stuff into the old the branch.
Though I do believe the other answers and comments have some very good points.

Can gems be assigned different interpreters?

I fee like I've seen that this was possible in some documentation before, but now I'm not able to find it. Is it possible to have a gemfile like:
gem "somegem", :interpreter => :MRI
gem "othergem", :interpreter => :macruby
etc, etc
I am needing this because in macruby some gems do not work, so it'd be great if you could get around that this way.
Are you looking for the platforms parameters? :platforms => mri_19 and so on. They only alow you to specify which gems to run under the current platform not how to run the gems.
EDIT: Anyways if you are not building any Cocoa applications use CRuby (MRI) by default, as it the most complete implementation of Ruby, or try RVM for handling multiple Ruby installations.

Easy way to distribute ruby script

I have a bunch of ruby scripts in a folder which is added to $PATH and I think that some of them might be usefult to others. So I want to distribute them and the only 'good' way I know is rubygems (gem containing only binary), it has a very useful advantage of versioning, but also a drawback of initialization time (sometimes it takes some seconds before script starts to run). Are there alternatives?
Gem is good enought for this. I use gem for this purposes as it is very convenient to intall and update.
Gems are built for this. I'm not sure what you think a gem is, but RubyGems is a repository like PEAR for PHP, aptitude for ubuntu, or CPAN for perl, except they contain ruby libraries.
There is no extra overhead or "initialization time" added to your ruby libraries by making them gems. RubyGems simply installs your library - it doesn't do anything else.
Gems are fine for this kind of Ruby script.
To quickly generate a new gem, try out bundle gem.
To quickly distribute gems without using rubygems.org, and in a way that could work for private deployment, check out the idea for microgems.
If you still don't think you need to wrap these in gems, you can simply add the executable bit to your scripts, add shebang lines for ruby, and remove the .rb extension. Then share your script files with whoever wants them.

Ruby: just-in-time gem installation?

Would it be possible to override the default "require" by adding automatic download-and-install code for any missing includes (provided that the missing include is published as a ruby gem).
Which would not work in situations where Ruby is not interfaced with a shell. But still I think it would be an interesting idea.
Is there such a mechanism in existence today?
Edit:Removed portion about password check. I just checked and gem install doesn't seem to require me to type my password.
You would be able to hijack require method so as gems are installed when an attempt is made to require them, but still you won't have access to newly installed gem in current process, because gem index has to be reloaded.
I understand the intentions but I think exercise might not be worth it.
When installing a fresh gem the gem will be installed in the GEM_HOME. If that is not writable then it will try in the user's home .gem directory (on *NIX at least).
You could certainly script this. In a way Rail's rake gems:build is just this. Just not on demand.
But, I would recommend against this. You could run into build, versioning, dependency and network issues. And probably security issues as well.
PS: Francis Hwang did something related a while ago, although only as a require, not a require gems.
http://fhwang.net/2005/11/01/urirequire-I-got-yer-Web-2-0-right-here
A better option would be to use bundler and distribute the required gems with the application.
It is also quite simple to write a script to bootstrap the installation of gems if you didn't
want to distribute them with your code (using the bundle install/check commands)

Resources