Rubygems, Bundler and Rvm Confusion

Rubygems, Bundler and RVM confusion

1. To find out where gems are being installed to, run echo $GEM_HOME in a terminal.
2. When using RVM, gems are installed into your RVM install as it changes $GEM_HOME. Running echo $GEM_HOME now would show a path into your RVM install.
3. When Bundler is added to the mix, gems will either be installed in $GEM_HOME, or, if you specify a path when running bundle install will be installed to that path. To find out where a gem is through Bundler you can use bundle show gemname to get its full path.

Relationships between Rubygems, Bundler, and RVM

From Bundler's website:

Bundler makes it easy to make sure that your application has the dependencies it needs to start up and run without errors.

This means that it's trivial for some other developer, or you on another machine, to get ready to develop further or use it, by running bundle install and you have everything you need to get up and running.

RVM is for managing multiple versions of Ruby on the same machine, and switching between them. Gemsets is a powerful feature RVM provides that isolates gems for one application/library from the rest of your system.

When using RVM and Bundler together, RVM tells Bundler where the gems should go, and Bundler installs them into the RVM-folder.

Both (with regards to gems in RVMs case) use and depend on Rubygems, so they're closest to wrappers.

I, personally, use Bundler and RVM for all my projects. No gemsets, just Bundler to resolve and fix things, which it does without fail. Installing gems is done without sudo, and ends up in the place RVM defines. The default Ruby install on my system is left alone, and nothing is installed to Rubygems system/user path

bundler vs RVM vs gems vs RubyGems vs gemsets vs system ruby

As per the previous answer, this is quite a lot to cover, so consider this a short introduction.

gems are the way Ruby libraries are packaged. They are to Ruby what jars are to Java. Inside a gem file, you find Ruby code (.rb files), but also tests, and a special file giving information on the gem itself, such as its name, dependencies and version (gemspec). Any Ruby project can define the gems it needs via a Gemfile that just need to declare dependencies. Rubygems is the name of the package manager - the tool used to install the packages (while the gems are the packages themselves). Rubygems is now part of Ruby.

Bundler is what makes managing gems bearable. Based on your Gemfile, a simple call to bundler using bundle install will download and install all the required gems. Using standard gem command, you would have to install each of them manually, using gem install <gem_name>. Bundler is not part of Ruby (it is itself packaged as a gem), but it a "de facto standard" for most applications (you will not find many people not using it, and no good reasons not to use it, actually).

RVM is a tool allowing you to install multiple versions of Ruby on a machine, switching between them when needed. This can be used to install both a Ruby 1.8 and 1.9, or even a "MRI" (Matz's Ruby, the default implementation) and alternatives (such as JRuby or Rubinius). Note that RVM is not alone in this field, see for instance rbenv.

A gemset in RVM is a set of gems specific to a given context, typically a project. This is useful if you are for example developing different applications, each with its own sets of gems, and want to keep them separate.

system Ruby is, when using RVM, the Ruby version installed on the machine (ie, not via RVM).

If you are just starting, gems and bundler are of interest to you. You can let RVM and gemsets aside for now.

I'm using RVM, what is the difference between using bundle install and rvm bundle install?

I think from this question, that you've not quite grasped the difference between rvm and bundler and what exactly each does. I'll try and explain the difference.

RVM is an acronym for Ruby enVironment (Version) Manager. It's a set of command-line scripts to help "sandbox" ruby binaries and gems for a project or set of projects. This way if you have one project that requires Ruby 1.8 and another that uses Ruby 1.9, you can switch easily between the two ruby installations and avoid nasty incompatibilities or cumbersome configuration.

You can also install different gemsets with each ruby version, so if you need to develop some applications with Ruby on Rails 2.3 and some with 3.0, or if you want to try the new 3.1 prelease, you can do so without breaking other applications' dependencies.

Bundler is a ruby gem which, as the website says, manages an application's dependencies through its entire life across many machines systematically and repeatably.

Bundler makes it easy to copy one application's source from one machine to another and install all the gems and dependencies needed by that particular application quickly and (relatively) painlessly.

So I understand the confusion as there is a bit of overlap. RVM gemsets are similar to gem bundles. The difference is that bundler manages the gems and dependencies for a single application and across multiple machines. An rvm gemset is a sandbox that keeps a group of gems in one place, tied to a particular ruby installation on a single machine, sometimes used for multiple applications.

So to close, when you say you "loaded up an rvm project" in your IDE, that's not particularly true. RVM is a sandbox, not a framework.

Bundler is being blocked by Rubygems website using RVM with Ruby 2.3.0

The solution to this problem was to edit the Gemfile file and change:

source "http://rubygems.org"

to:

source "https://rubygems.org"

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