Extract CI config YAML parser to a separate class

With this approach it would be easier to add different sources of
configuration, that we do not necessairly have to be in YAML format.

2 files changed, 29 insertions, 4 deletions

diff --git a/lib/gitlab/ci/config.rb b/lib/gitlab/ci/config.rb
index 8f88ccf5bf4..0baefa70f61 100644
--- a/lib/gitlab/ci/config.rb
+++ b/lib/gitlab/ci/config.rb
@@ -4,13 +4,13 @@ module Gitlab
       class ParserError < StandardError; end
 
       def initialize(config)
-        @config = YAML.safe_load(config, [Symbol], [], true)
+        parser = Parser.new(config)
 
-        unless @config.is_a?(Hash)
-          raise ParserError, 'YAML should be a hash'
+        unless parser.valid?
+          raise ParserError, 'Invalid configuration format!'
         end
 
-        @config = @config.deep_symbolize_keys
+        @config = parser.parse
       end
 
       def to_hash
diff --git a/lib/gitlab/ci/config/parser.rb b/lib/gitlab/ci/config/parser.rb
new file mode 100644
index 00000000000..6e1b7ec8267
--- /dev/null
+++ b/lib/gitlab/ci/config/parser.rb
@@ -0,0 +1,25 @@
+module Gitlab
+  module Ci
+    class Config
+      class Parser
+        class FormatError < StandardError; end
+
+        def initialize(config)
+          @config = YAML.safe_load(config, [Symbol], [], true)
+        end
+
+        def valid?
+          @config.is_a?(Hash)
+        end
+
+        def parse
+          unless valid?
+            raise FormatError, 'Invalid configuration format'
+          end
+
+          @config.deep_symbolize_keys
+        end
+      end
+    end
+  end
+end