Fabric provisioner for Vagrant 1.2

plugins provisioners fabric config.rb

module VagrantPlugins
  module Fabric
    class Config < Vagrant.plugin("2", :config)
      attr_accessor :fabfile_path
      attr_accessor :fabric_path
      attr_accessor :python_path
      attr_accessor :tasks

      def initialize
        @fabfile_path = UNSET_VALUE
        @fabric_path  = UNSET_VALUE
        @python_path  = UNSET_VALUE
        @tasks        = UNSET_VALUE
      end

      def finalize!
        @fabfile_path = "fabfile.py" if @fabfile_path == UNSET_VALUE
        @fabric_path = "fab" if @fabric_path == UNSET_VALUE
        @python_path = "python" if @python_path == UNSET_VALUE
        @tasks = [] if @tasks == UNSET_VALUE
      end

      def validate(env)
        errors = _detected_errors

        if not File.exist?(fabfile_path)
          errors << "No fabfile found."
        end

        which_fabric_path = `which #{fabric_path}`
        if not $?.success?
          errors << "fabric command does not exist."
        end
        
        which_python_path = `which #{python_path}`
        if not $?.success?
          errors << "python not found."
        end

        fabfile_package = fabfile_path.gsub(".py", "").gsub("/", ".")
        output = `#{python_path} -c "exec 'import #{fabfile_package}'" &> /dev/null`
        if not $?.success?
          errors << "#{fabfile_package} could not import."
        end

        for task in tasks
          task = task.split(":")[0]
          package_path = "#{fabfile_package}.#{task}".gsub(".__init__", "")
          packages = package_path.split(".")
          output = `#{python_path} -c "exec 'from #{packages[0..-2].join('.')} import #{packages[-1]}'" > /dev/null 2>&1`
          if not $?.success?
            errors << "#{task} task does not exist."
          end
        end
        { "fabric provisioner" => errors }
      end
    end
  end
end

plugins provisioners fabric plugin.rb

require "vagrant"

module VagrantPlugins
  module Fabric
    class Plugin < Vagrant.plugin("2")
      name "fabric"

      config(:fabric, :provisioner) do
        require File.expand_path("../config", __FILE__)
        Config
      end

      provisioner(:fabric) do
        require File.expand_path("../provisioner", __FILE__)
        Provisioner
      end
    end
  end
end

plugins provisioners fabric provisioner.rb

module VagrantPlugins
  module Fabric
    class Provisioner < Vagrant.plugin("2", :provisioner)
      def provision
        ssh_info = machine.ssh_info
        user = ssh_info[:username]
        host = ssh_info[:host]
        port = ssh_info[:port]
        private_key = ssh_info[:private_key_path]
        system "#{config.fabric_path} -i #{private_key} --config=#{config.fabfile_path} --user=#{user} --hosts=#{host} --port=#{port} #{config.tasks.join(' ')}"
      end
    end
  end
end

Vagrantfile

require_relative "plugins/provisioners/fabric/plugin.rb"

Vagrant.configure("2") do |config|
  *snip*
  config.vm.provision :fabric do |fab|
    fab.tasks = ["setup_salt:kwarg=value"]
  end
end

I have published the new version of vagrant-fabric plugin here (https://rubygems.org/gems/vagrant-fabric).
You can install it with just typing "vagrant plugin install vagrant-fabric".

And I changed my source code using your forked version.
Thank you for your contribution :)