在来宾linux virtualbox上运行rails：一个database.yml问题

Question

a) I'm a ruby in rails beginner developer, and I use windows 7 machine as developement environment...

b) With VirtualBox I just installed, inside the Windows 7 "host", a Linux ubuntu sever "guest", just to run the rails DEVELOPMENT environment ALSO in the linux machine.

c) To do that I configured a virtualbox SHARED FOLDER: let say I have this shared folder on the host machine (window):

c:\\rails\\esamiAnatomia

and mounted it on the linux embedded server:

/home/solyaris/host/esamianatomia

d) In this exptended "developement environment" I would like to edit source files with my preferred visual editor on windows (sublime text) and run rails server on linux.

The problem concern database.yml configuration file:

/home/solyaris/host/esamianatomia/config/database.yml

because on Windows I have a database (postgresql) responding port 5433, with specific username/password

but in linux database respond to port 5432, etc.

Questions:

1) It's that "arcgitectural solution ok ? (I mean: developing/editing from a windows 7 host, but running rails server of the linux guest server);

2) There is a way to change/configure database.yml on the fly (I mean: using two different database.yml files: one for the linux machine and anotherone for the window machine) ?

thanks a lot giorgio

Answer 1

You can technically accomplish 2 if you're not afraid to play around with the guts of Rails. As with any solution that has you accessing internal rails components this may stop working at any time, but fortunately this part of the API is not likely to change often, if ever. Still, use this at your own risk.

Here's how I do it on my projects. First modify your application as follows:

# config/application.rb:

# After require 'rails/all'
require_relative 'db_override'

Then create this new file:

# config/db_override.rb:
case Socket.gethostname
when 'host1'
  $db_config = 'config/host1_database.yml'
when 'host2'
  $db_config = 'config/host2_database.yml'
else
  $db_config = nil # Use the default config/database.yml
end

if $db_config
  class DBConfigSelect < Rails::Railtie
    initializer "db_config_select", before: "active_record.initialize_database" do
      puts "Using custom DB configuration: #{$db_config}"

      # Get the existing path configuration
      cur_paths = Rails.application.config.paths['config/database'].instance_variable_get :@paths

      # Override the default config sources
      cur_paths.shift
      cur_paths.push $db_config
    end
  end
end

Answer 2

What you are describing is pretty much the setup that Vagrant is offering, so yeah, you are doing fine, everyone else is also doing it but they didn't set it up themselves (and by that probably get some really nice addons as well, you should take a look at Vagrant).

For your second question: no. Not on the fly. Rails loads the database.yml end then connects to the database with that. When you change it while your Rails server is running, the changes won't get noticed. What you can do however is setup a new environment for your two different machines. Then you can switch between the different environments and depending on the environment, one or the other database gets accessed.