How to Use Rvm and Create Globally Available Gems

How do I use RVM and create globally available gems?

There is something called the global gemset, and it is shared between all your gemsets of a certain ruby-version. But you can't share gems between ruby-versions.

However, what you can do is create a list of gems that will be installed automatically when adding a new ruby version. That is described here. In short: edit a file called ~/.rvm/gemsets/global.gems to contain the list of gems you want to be there for each ruby-version.

Hope it helps.

RVM | Obtrusive gems in the global gemset

this gems are part of ruby distribution:

bigdecimal (1.2.3)
io-console (0.4.2)
json (1.8.1)
minitest (4.7.5)
psych (2.0.2)
rake (10.1.0)
rdoc (4.1.0)
test-unit (2.1.0.0)

this gem is part of rvm and is required for rvm to function properly:

gem-wrappers (1.2.3)

RVM global gemset confusion

In common:

rvm <ruby version>@<gemset name> do gem list

For example:

rvm @test do gem list

show that you want: gems on test gemset environment

Another way:

rvm use @test
gem list

show the same

Gem installed in @global gemset is not available in other gemsets

looks like your GEM_PATH is broken, pleas run:

export GEM_PATH=/Users/andy/.rvm/gems/ruby-2.2.3:/Users/andy/.rvm/gems/ruby-2.2.3@global

and try again:

bro

RVM system-wide gemsets

Use mixed mode installation of RVM basically you get system installation and as every user that should have his own gemsets run:

rvm user gemsets

Whats the command to let rvm use default (like global) gemset for every new rails application I create?

You can specify a "default" gemset for a given ruby interpreter, by doing:

rvm use ruby-1.9.2-p0@gemsetname --default

See: http://beginrescueend.com/gemsets/using/ and http://beginrescueend.com/gemsets/basics/

it's probably a better idea to use a specific gemset for each of your projects, together with it's specific Gemfile. Problems could happen if you require '>= x.y.z' in your Gemfiles, and you do a bundle update in one project, but not in the other...

cd ProjectA
rvm gemset create projecta
rvm gemset use projecta

cd ProjectB
rvm gemset create projectb
rvm gemset use projectb

This way, although you update the gems in ProjectA via bundle update to the latest and greatest, they still don't get modified for ProjectB -- eliminating the possibility for interference between projects.

you can also add a .rvmrc file to a directory, e.g. your project directory. RVM will then use the ruby-version and gem set listed in the .rvmrc file as the default for all sub-directories.

e.g. assuming that you have ruby 1.9.3 installed, and a gem set "rails_3.2" for that ruby version:

# cat .rvmrc
rvm use ruby-1.9.3-p0@rails_3.2

How to reduce duplicate gems with RVM and Bundler?

If you wanna install a gem per ruby, you need to do a gem install pry for instance. That will install the gem on the ruby level. After that you can require that in your Rails app, for instance on the boot.rb file.
I am not sure how rvm deals with gemsets. If what they do is change the entire folder reference of the gem command, then you wont be able to do that. I would need to install those gems for every gemset, which is a PITA.

On my workflow, I dont need gemsets, as I have bundler. So I use rbenv to install and change ruby versions, and let bundler deals with gems for a project. Like so, I can install a gem, globally per ruby, and it works.

How do RVM rubies find gems?

Try adding a require 'rubygems' at the top of your source file. In 1.8 rubygems aren't required by default.

Thus said, regarding gem paths:

GEM_HOME indicates where gems are installed. To find out what it is for your case do:

$ echo $GEM_HOME

This should display an RVM-related path, since RVM changes this environment variable in order to make the $ gem install command install gems in its directories.

Globally available Gemfile

Make a Gemfile as usual, and place it in any folder. It does not need to be a project folder. Then you can just do:

bundle install --system

This will install the gems in the Gemfile system-wide, and will ask for the root password if you do not have access to the system folder.

--system:
Installs the gems in the bundle to the system location. This overrides any previous remembered use of --path.

You can also name your Gemfile(s), if you want to organize them in some way:

bundle install --system --gemfile=/path/to/my_special_gemfile