How does RVM work in production with no users logged in?

Question

Considering putting RVM into production (light duty) on a new machine. But I'm not visualizing how it will work if a user isn't logged in. RVM has been installed into /usr/local/rvm/bin/rvm so it is available to "everyone".

If server restarts and is at login screen and background daemons are serving apache/rails, etc. and no .bashrc, etc. have loaded...how/where do we specify which of RVM's Rubies to load?

Perhaps somewhere in Phusion's Passenger?

who manages these gemsets? are they shared?

Answer 1

You can use RVM's wrapper command to generate scripts that load up the correct RVM environment before executing the necessary binaries. The format is:

rvm wrapper [ruby_string] [wrapper_prefix] [binary[ binary[ ...]]]

For example, to create a binary named system_unicorn that loads ruby-1.9.2-p180 and then executes unicorn, use the following:

rvm wrapper ruby-1.9.2-p180 system unicorn

You can pass multiple binaries to create wrappers for. For example, to create wrappers for both unicorn and god, run

rvm wrapper ruby-1.9.2-p180 system unicorn god

ruby_string can be anything you can pass to rvm use, and thus can contain gemsets as well; for example, to create myapp_unicorn for the gemset my_app_gemset, use:

rvm wrapper ruby-1.9.2-p180@my_app_gemset myapp unicorn

When you install Passenger these days, it automatically creates a wrapper for it's ruby (pretty sure it calls it passenger_ruby) that loads up the correct version of Ruby (the one you're using when you install it). You can use config/setup_load_paths.rb to specify a gemset--see this Stack Overflow answer.