Is it possible to execute ruby code inside a Vagrantfile?

[Luis Mayorga]

I need to detect which platform is running vagrant. (We have vagrant windows/mac users) and need to setup some initial variable values for some of the configuration parameters.

[Terrance Shepherd]

Yes, just put in the code.

On Thu, Mar 20, 2014 at 4:25 PM, Luis Mayorga <lmayor...@gmail.com> wrote:

I need to detect which platform is running vagrant. (We have vagrant windows/mac users) and need to setup some initial variable values for some of the configuration parameters.

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[Jeremy Voorhis]

The Vagrantfile is just a Ruby file that gets evaluated within a special context that implements the Vagrant DSL. You can definitely execute arbitrary Ruby code to specialize your VM.

On Thu, Mar 20, 2014 at 1:25 PM, Luis Mayorga <lmayor...@gmail.com> wrote:

I need to detect which platform is running vagrant. (We have vagrant windows/mac users) and need to setup some initial variable values for some of the configuration parameters.

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[Luis Mayorga]

This worked!!!

if Gem.win_platform?

Thanks

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[Alvaro Miranda Aguilera]

in one Vagrantfile I found on github,. they use this.

      if RUBY_PLATFORM.include? 'linux'
          b.vm.network :bridged, :bridge => "eth0"
      elseif RUBY_PLATFORM.include? 'darwin'
          b.vm.network :bridged, :bridge => "en1: Wi-Fi (AirPort)"
      end

I assume, you can check if there is a in/windows or something.

Alvaro.

[blong]

I'm new to Ruby, so pardon my ignorance, but is there a way to load rubygems and require additional libraries?  For example, let's say I wanted to assign %25 of the CPU cores to Vagrant.  I need something that's platform independent, I was thinking something like this:

    require 'rubygems'
    require 'facter'
    Facter.loadfacts
   
    config.vm.provider "virtualbox" do |v|
      # Give VM 25% of system cpu cores
      v.customize ["modifyvm", :id, "--cpus", [((Facter.processorcount) / 4).to_i, 1].max ]
    end

Any thoughts on how I can achieve this?

Thanks,

blong

[Alvaro Miranda Aguilera]

Hello,

Try the attached on top of your Vagrantfile.

Vagrant includes his own ruby and some gems, I did copy this from celluloid/cpucount, and tested on OSX.

then, on the config block you can do something like this:

config.vm.provider "virtualbox" do |v|
      # Give VM 25% of system cpu cores


      if @cores


        v.customize ["modifyvm", :id, "--cpus", @cores/4.to_i ]

      end


    end



[blong]

Hi Alvaro,

Thanks for your suggestion.  Is there a place where documentation for variables like @cores
is available?  I tried something similar, per your suggestion (below), however the output is always : "Unable to detect CPU cores, will assign 1 CPU to the VM".

    # Give VM 25% of system cpu cores, with a minimum of 1
    if @cores
      puts "Detected " + @cores + " CPU cores"
      v.customize ["modifyvm", :id, "--cpus", max([@cores/4.to_i, 1]) ]
    else
      puts "Unable to detect CPU cores, will assign 1 CPU to the VM"
    end

Thanks again,

blong

[Alvaro Miranda Aguilera]

did you put the code I sent attached to the email to the beggining to vagrantfile?

@code is defined/created in the ruby code i sent

# -*- mode: ruby -*-

# vi: set ft=ruby : 

require 'rbconfig'  

case RbConfig::CONFIG['host_os'][/^[A-Za-z]+/]  

when 'darwin'   

  @cores = Integer(`/usr/sbin/sysctl hw.ncpu`[/\d+/])   

when 'linux'

  @cores = if File.exists?("/sys/devices/system/cpu/present")   

File.read("/sys/devices/system/cpu/present").split('-').last.to_i+1 

  else  

Dir["/sys/devices/system/cpu/cpu*"].select { |n| n=~/cpu\d+/ }.count

  end   

when 'mingw', 'mswin'   

  @cores = Integer(ENV["NUMBER_OF_PROCESSORS"][/\d+/])  

else

  @cores = nil  

end 

puts @cores 

# Vagrantfile API/syntax version. Don't touch unless you know what you're doing!

VAGRANTFILE_API_VERSION = "2" 

[blong]

Ah, I did not (at first).  Thanks for pointing that out, I completely missed the attachment earlier.  This worked perfectly for me after declaring the "@cores" variable!

[Jamie Jackson]

FWIW, here's how I'm detecting OS and bitness: https://gist.github.com/jamiejackson/39787215b5fc6ed22e7e