Add support for Cloud Foundry

Signed-off-by: Gamaliel Amaudruz <gamaudruz@pivotal.io>

Author: Alan Yeo

README.md

@@ -333,6 +333,16 @@ filesystem gets recreated from the git sources on each instance refresh. To use
 
 To upload your local values to Heroku you could ran `bundle exec rake config:heroku`.
 
+### Working with Cloud Foundry
+
+Cloud Foundry integration will generate a manifest adding to your CF manifest.yml the defined ENV variables under the `env` section of specified app in the yaml file.
+You must specify the app name and optionally the name of your CF manifest file:
+
+    bundle exec rake config:cf[app_name, cf_manifest.yml]
+    
+The result of this command will have the manifest file name suffixed with the environment you ran the task in. You can then push your app with the generated manifest.    
+
+
 ### Fine-tuning
 
 You can customize how environment variables are processed:

lib/config/integrations/cloud_foundry.rb

@@ -0,0 +1,27 @@
+require 'bundler'
+require 'yaml'
+require_relative '../../../lib/config/integrations/helpers/cf_manifest_merger'
+
+module Config
+  module Integrations
+    class CloudFoundry < Struct.new(:app_name, :file_path)
+
+      def invoke
+        manifest_path = file_path || 'manifest.yml'
+        file_name, _ext = manifest_path.split('.yml')
+
+        manifest_hash = YAML.load(IO.read(File.join(::Rails.root, manifest_path)))
+
+        puts "Generating manifest... (base cf manifest: #{manifest_path})"
+
+        merged_hash = Config::CFManifestMerger.new(app_name, manifest_hash).add_to_env
+
+        target_manifest_path = File.join(::Rails.root, "#{file_name}-#{::Rails.env}.yml")
+        IO.write(target_manifest_path, merged_hash.to_yaml)
+
+        puts "File #{target_manifest_path} generated."
+      end
+
+    end
+  end
+end

lib/config/integrations/helpers/cf_manifest_merger.rb

@@ -0,0 +1,38 @@
+require_relative 'helpers'
+
+module Config
+  class CFManifestMerger
+    include Integrations::Helpers
+
+    def initialize(app_name, manifest_hash)
+      @app_name = app_name
+      @manifest_hash = manifest_hash
+      raise ArgumentError.new("Manifest path & app name must be specified") unless @app_name && @manifest_hash
+    end
+
+    def add_to_env
+
+      settings_hash = Config.const_get(Config.const_name).to_hash.stringify_keys
+
+      prefix_keys_with_const_name_hash = to_dotted_hash(settings_hash, namespace: Config.const_name)
+
+      app_hash = @manifest_hash['applications'].detect { |hash| hash['name'] == @app_name }
+
+      raise ArgumentError, "Application '#{@app_name}' is not specified in your manifest" if app_hash.nil?
+
+      check_conflicting_keys(app_hash['env'], settings_hash)
+
+      app_hash['env'].merge!(prefix_keys_with_const_name_hash)
+
+      @manifest_hash
+    end
+
+    private
+
+    def check_conflicting_keys(env_hash, settings_hash)
+      conflicting_keys = env_hash.keys & settings_hash.keys
+      raise ArgumentError.new("Conflicting keys: #{conflicting_keys.join(', ')}") if conflicting_keys.any?
+    end
+
+  end
+end

lib/config/integrations/helpers/helpers.rb

@@ -0,0 +1,21 @@
+module Config::Integrations::Helpers
+
+  def to_dotted_hash(source, target: {}, namespace: nil)
+    raise ArgumentError, "target must be a hash (given: #{target.class.name})" unless target.kind_of? Hash
+    prefix = "#{namespace}." if namespace
+    case source
+      when Hash
+        source.each do |key, value|
+          to_dotted_hash(value, target: target, namespace: "#{prefix}#{key}")
+        end
+      when Array
+        source.each_with_index do |value, index|
+          to_dotted_hash(value, target: target, namespace: "#{prefix}#{index}")
+        end
+      else
+        target[namespace] = source
+    end
+    target
+  end
+
+end

lib/config/integrations/heroku.rb

@@ -1,8 +1,11 @@
 require 'bundler'
+require_relative 'helpers/helpers'
 
 module Config
   module Integrations
     class Heroku < Struct.new(:app)
+      include Integrations::Helpers
+
       def invoke
         puts 'Setting vars...'
         heroku_command = "config:set #{vars}"
@@ -14,13 +17,13 @@ def invoke
       def vars
         # Load only local options to Heroku
         Config.load_and_set_settings(
-            Rails.root.join("config", "settings.local.yml").to_s,
-            Rails.root.join("config", "settings", "#{environment}.local.yml").to_s,
-            Rails.root.join("config", "environments", "#{environment}.local.yml").to_s
+            ::Rails.root.join("config", "settings.local.yml").to_s,
+            ::Rails.root.join("config", "settings", "#{environment}.local.yml").to_s,
+            ::Rails.root.join("config", "environments", "#{environment}.local.yml").to_s
         )
 
         out = ''
-        dotted_hash = to_dotted_hash Kernel.const_get(Config.const_name).to_hash, {}, Config.const_name
+        dotted_hash = to_dotted_hash Kernel.const_get(Config.const_name).to_hash, namespace: Config.const_name
         dotted_hash.each {|key, value| out += " #{key}=#{value} "}
         out
       end
@@ -38,22 +41,6 @@ def `(command)
         Bundler.with_clean_env { super }
       end
 
-      def to_dotted_hash(source, target = {}, namespace = nil)
-        prefix = "#{namespace}." if namespace
-        case source
-          when Hash
-            source.each do |key, value|
-              to_dotted_hash(value, target, "#{prefix}#{key}")
-            end
-          when Array
-            source.each_with_index do |value, index|
-              to_dotted_hash(value, target, "#{prefix}#{index}")
-            end
-          else
-            target[namespace] = source
-        end
-        target
-      end
     end
   end
 end

lib/config/integrations/rails/railtie.rb

@@ -15,7 +15,7 @@ def preload
 
         # Load rake tasks (eg. Heroku)
         rake_tasks do
-          Dir[File.join(File.dirname(__FILE__), '../tasks/*.rake')].each { |f| load f }
+          Dir[File.join(File.dirname(__FILE__), '../../tasks/*.rake')].each { |f| load f }
         end
 
         config.before_configuration { preload }

lib/config/tasks/cloud_foundry.rake

@@ -0,0 +1,10 @@
+require 'config/integrations/cloud_foundry'
+
+namespace 'config' do
+
+  desc 'Create a cf manifest with the env variables defined by config under current environment'
+  task :'cf', [:app_name, :file_path] => :environment do |_, args|
+    Config::Integrations::CloudFoundry.new(args[:app_name], args[:file_path]).invoke
+  end
+
+end

lib/config/tasks/heroku.rake

@@ -1,7 +1,10 @@
 require 'config/integrations/heroku'
 
 namespace 'config' do
+
+  desc 'Upload to Heroku all env variables defined by config under current environment'
   task :heroku, [:app] => :environment do |_, args|
     Config::Integrations::Heroku.new(args[:app]).invoke
   end
+
 end

spec/fixtures/cf/cf_conflict.yml

@@ -0,0 +1,2 @@
+DEFAULT_HOST: host
+DEFAULT_PORT: port

spec/fixtures/cf/cf_manifest.yml

@@ -0,0 +1,11 @@
+applications:
+- name: some-cf-app
+  instances: 1
+  env:
+    DEFAULT_HOST: host
+    DEFAULT_PORT: port
+    FOO: BAR
+
+- name: app_name
+  env:
+    DEFAULT_HOST: host