extracted rsync class, only using ssh keys that exist

Rakefile

@@ -1,3 +1,11 @@
+require 'rake/testtask'
+
+Rake::TestTask.new do |t|
+  t.test_files = FileList['test/*_test.rb']
+end
+
+task :default => :test
+
 desc "clean"
 task :clean do
   rm_f Dir.glob("*.gem")

lib/supply_drop.rb

@@ -1,3 +1,5 @@
+require 'supply_drop/rsync'
+
 Capistrano::Configuration.instance.load do
   namespace :puppet do
     set :puppet_target, '/home/vagrant/supply_drop'
@@ -14,7 +16,13 @@
     desc "pushes the current puppet configuration to the server"
     task :update_code, :except => { :nopuppet => true } do
       find_servers_for_task(current_task).each do |server|
-        rsync_cmd = "rsync -az --delete --exclude=.git -e 'ssh -i #{ssh_options[:keys]}' . #{server.user || user}@#{server.host}:#{puppet_target}/"
+        rsync_cmd = Rsync.command(
+          ".",
+          "#{server.user || user}@#{server.host}:#{puppet_target}/",
+          :delete => true,
+          :excludes => ['.git'],
+          :ssh => { :keys => ssh_options[:keys] }
+        )
         logger.debug rsync_cmd
         system rsync_cmd
       end

lib/supply_drop/rsync.rb

@@ -0,0 +1,26 @@
+class Rsync
+  class << self
+    def command(from, to, options={})
+      flags = ['-az']
+      flags << '--delete' if options[:delete]
+      flags << excludes(options[:excludes]) if options.has_key?(:excludes)
+      flags << ssh_options(options[:ssh]) if options.has_key?(:ssh)
+
+      "rsync #{flags.compact.join(' ')} #{from} #{to}"
+    end
+
+    def excludes(patterns)
+      [patterns].flatten.map { |p| "--exclude=#{p}" }
+    end
+
+    def ssh_options(options)
+      mapped_options = options.map do |key, value|
+        if key == :keys
+          [value].flatten.select { |k| File.exist?(k) }.map { |k| "-i #{k}" }
+        end
+      end
+
+      %[-e "ssh #{mapped_options.join(' ')}"]
+    end
+  end
+end

test/rsync_test.rb

@@ -0,0 +1,26 @@
+require 'test/unit'
+require File.expand_path('../../lib/supply_drop/rsync', __FILE__)
+
+class RsyncTest < Test::Unit::TestCase
+
+  def test_build_simple_command
+    command = Rsync.command('bar', 'foo')
+    assert_equal 'rsync -az bar foo', command
+  end
+
+  def test_allows_passing_delete
+    command = Rsync.command('bar', 'foo', :delete => true)
+    assert_equal 'rsync -az --delete bar foo', command
+  end
+
+  def test_allows_specifying_an_exclude
+    command = Rsync.command('bar', 'foo', :excludes => '.git')
+    assert_equal 'rsync -az --exclude=.git bar foo', command
+  end
+
+  def test_ssh_options_keys_only_lists_existing_files
+    command = Rsync.command('.', 'foo', :ssh => { :keys => [__FILE__, "#{__FILE__}dadijofs"] })
+    assert_match /-i #{__FILE__}/, command
+  end
+
+end