Parse ERB code in configuration file

lib/gemnasium/configuration.rb

@@ -1,4 +1,5 @@
 require 'yaml'
+require 'erb'
 
 module Gemnasium
   class Configuration
@@ -23,7 +24,7 @@ def initialize config_file
       end
       @path = config_file
 
-      config_hash = DEFAULT_CONFIG.merge(YAML.load_file(config_file))
+      config_hash = DEFAULT_CONFIG.merge(YAML.load(ERB.new(File.read(config_file)).result))
       config_hash.each do |k, v|
         writer_method = "#{k}="
         if respond_to?(writer_method)

spec/gemnasium/configuration_spec.rb

@@ -69,6 +69,32 @@ def write_config_file
         it { expect(config.ignored_paths).to include Regexp.new("^[^\/]+\\.gemspec") }
       end
     end
+
+    context 'for a config file with parsable ERB code' do
+      before { write_config_file }
+      before { ENV['GEMNASIUM_API_KEY'] = 'api_key_from_env' }
+
+      let(:config_options) do
+        {
+          api_key: "<%= ENV['GEMNASIUM_API_KEY'] %>",
+          project_name: 'gemnasium-gem',
+          project_branch: 'master',
+          ignored_paths: ['spec/','tmp/*.lock', '*.gemspec']
+        }
+      end
+
+      it 'parses ERB code' do
+        expect(config.api_key).to eql 'api_key_from_env'
+      end
+
+      it 'keeps values unchanged if not ERB code' do
+        expect(config.project_name).to eql config_options[:project_name]
+        expect(config.project_branch).to eql config_options[:project_branch]
+        expect(config.ignored_paths).to include Regexp.new("^spec/")
+        expect(config.ignored_paths).to include Regexp.new("^tmp/[^/]+\\.lock")
+        expect(config.ignored_paths).to include Regexp.new("^[^\/]+\\.gemspec")
+      end
+    end
   end
 
   pending "writable?"