feat(global): support per-application deploy directory

Some Opsworks users deploy their apps on custom AMIs with strict
partitioning schemes and disk space limitations. For these users
the default deploy directory /srv/www is not always a good choice.

This patch allows users to override the deploy directory at the
application level by specifying the attribute

`node['deploy'][shortname]['global']['deploy_dir']`

The default value for the app-specific deploy directory continues to be
/srv/www/shortname.

Fixes #95

docs/source/attributes.rst

@@ -58,6 +58,15 @@ Global parameters apply to the whole application, and can be used by any section
   -  Sets the “deploy environment” for all the app-related (for example ``RAILS_ENV``
      in Rails) actions in the project (server, worker, etc.)
 
+-  ``app['global']['deploy_dir']``
+
+  -  **Type:** string
+  -  **Default:** ``/srv/www/app_name``
+  -  Determines where the application will be deployed.
+  -  Note that if you override this setting, you'll typically want to include the short_name
+     in the setting. In other words, this setting doesn't override the ``/srv/www`` base
+     directory defafult; it overrides the application-specific ``/srv/www/app_name`` default.
+
 - ``app['global']['symlinks']``
 
   -  **Type:** key-value

libraries/helpers.rb

@@ -61,7 +61,7 @@ def create_deploy_dir(application, subdir = '/')
 end
 
 def deploy_dir(application)
-  File.join('/', 'srv', 'www', application['shortname'])
+  globals('deploy_dir', application['shortname']) || ::File.join('/', 'srv', 'www', application['shortname'])
 end
 
 def every_enabled_application

spec/unit/recipes/deploy_spec.rb

@@ -228,4 +228,56 @@
     expect(chef_run).to deploy_deploy('a1')
     expect(chef_run).not_to deploy_deploy('a2')
   end
+
+  describe 'per-application deploy_dir' do
+    before do
+      stub_search(:aws_opsworks_app, '*:*').and_return([
+                                                         aws_opsworks_app.merge(shortname: 'a1', deploy: true)
+                                                       ])
+    end
+
+    let(:chef_run) do
+      ChefSpec::SoloRunner.new(platform: 'ubuntu', version: '14.04') do |solo_node|
+        solo_node.set['lsb'] = node['lsb']
+        solo_node.set['deploy'] = { 'a1' => {} }
+        if deploy_dir
+          solo_node.set['deploy']['a1']['global']['deploy_dir'] = deploy_dir
+        end
+      end.converge(described_recipe)
+    end
+
+    context 'when deploy_dir is not specified' do
+      let(:deploy_dir) { nil }
+
+      it 'deploys a1 using the default deploy directory of /srv/www' do
+        expect(chef_run).to create_directory('/srv/www/a1/shared')
+        expect(chef_run).to create_directory('/srv/www/a1/shared/config')
+        expect(chef_run).to create_directory('/srv/www/a1/shared/log')
+        expect(chef_run).to create_directory('/srv/www/a1/shared/pids')
+        expect(chef_run).to create_directory('/srv/www/a1/shared/scripts')
+        expect(chef_run).to create_directory('/srv/www/a1/shared/sockets')
+        expect(chef_run).to create_directory('/srv/www/a1/shared/vendor/bundle')
+        expect(chef_run).to create_template('/srv/www/a1/shared/config/database.yml')
+        expect(chef_run).to create_template('/srv/www/a1/shared/config/puma.rb')
+        expect(chef_run).to create_template('/srv/www/a1/shared/scripts/puma.service')
+      end
+    end
+
+    context 'when a deploy_dir is specified' do
+      let(:deploy_dir) { '/some/other/path/to/a1' }
+
+      it 'deploys a1 using the provided deploy directory instead' do
+        expect(chef_run).to create_directory('/some/other/path/to/a1/shared')
+        expect(chef_run).to create_directory('/some/other/path/to/a1/shared/config')
+        expect(chef_run).to create_directory('/some/other/path/to/a1/shared/log')
+        expect(chef_run).to create_directory('/some/other/path/to/a1/shared/pids')
+        expect(chef_run).to create_directory('/some/other/path/to/a1/shared/scripts')
+        expect(chef_run).to create_directory('/some/other/path/to/a1/shared/sockets')
+        expect(chef_run).to create_directory('/some/other/path/to/a1/shared/vendor/bundle')
+        expect(chef_run).to create_template('/some/other/path/to/a1/shared/config/database.yml')
+        expect(chef_run).to create_template('/some/other/path/to/a1/shared/config/puma.rb')
+        expect(chef_run).to create_template('/some/other/path/to/a1/shared/scripts/puma.service')
+      end
+    end
+  end
 end