Support the yaml extension for parameter files

README.md

@@ -143,10 +143,13 @@ template_compilers:
 
 ## Parameters
 
-Parameters are loaded from multiple YAML files, merged from the following lookup paths:
+Parameters are loaded from multiple YAML files, merged from the following lookup paths from bottom to top:
 
+- parameters/[stack_name].yaml
 - parameters/[stack_name].yml
+- parameters/[region]/[underscored_stack_name].yaml
 - parameters/[region]/[underscored_stack_name].yml
+- parameters/[region_alias]/[underscored_stack_name].yaml
 - parameters/[region_alias]/[underscored_stack_name].yml
 
 A simple parameter file could look like this:

lib/stack_master/stack_definition.rb

@@ -84,16 +84,16 @@ def s3_configured?
     def additional_parameter_lookup_file_paths
       return unless additional_parameter_lookup_dirs
       additional_parameter_lookup_dirs.map do |a|
-        File.join(base_dir, 'parameters', a, "#{underscored_stack_name}.yml")
+        Dir.glob(File.join(base_dir, 'parameters', a, "#{underscored_stack_name}.y*ml"))
       end
     end
 
     def region_parameter_file_path
-      File.join(base_dir, 'parameters', "#{region}", "#{underscored_stack_name}.yml")
+      Dir.glob(File.join(base_dir, 'parameters', "#{region}", "#{underscored_stack_name}.y*ml"))
     end
 
     def default_parameter_file_path
-      File.join(base_dir, 'parameters', "#{underscored_stack_name}.yml")
+      Dir.glob(File.join(base_dir, 'parameters', "#{underscored_stack_name}.y*ml"))
     end
 
     def underscored_stack_name

spec/stack_master/parameter_loader_spec.rb

@@ -54,6 +54,23 @@
     end
   end
 
+  context 'yml and yaml region parameter files' do
+    let(:stack_file_returns) { {exists: false} }
+    let(:region_file_returns) { {exists: true, read: "Param2: value2"} }
+    let(:region_yaml_file_returns) { {exists: true, read: "Param1: value1\nParam2: valueX"} }
+    let(:region_yaml_file_name) { "/base_dir/parameters/us-east-1/stack_name.yaml" }
+
+    subject(:parameters) { StackMaster::ParameterLoader.load([stack_file_name, region_yaml_file_name, region_file_name]) }
+
+    before do
+      file_mock(region_yaml_file_name, region_yaml_file_returns)
+    end
+
+    it 'returns params from the region base stack_name.yml' do
+      expect(parameters).to eq(template_parameters: {'Param1' => 'value1', 'Param2' => 'value2'}, compile_time_parameters: {})
+    end
+  end
+
   context 'compile time parameters' do
 
     context 'stack parameter file' do

spec/stack_master/stack_definition_spec.rb

@@ -14,23 +14,56 @@
   let(:tags) { {'environment' => 'production'} }
   let(:base_dir) { '/base_dir' }
 
+  before do
+    allow(Dir).to receive(:glob).with(
+      File.join(base_dir, 'parameters', "#{stack_name}.y*ml")
+    ).and_return(
+      [
+        "/base_dir/parameters/#{stack_name}.yaml",
+        "/base_dir/parameters/#{stack_name}.yml",
+      ]
+    )
+
+    allow(Dir).to receive(:glob).with(
+      File.join(base_dir, 'parameters', "#{region}", "#{stack_name}.y*ml")
+    ).and_return(
+      [
+        "/base_dir/parameters/#{region}/#{stack_name}.yaml",
+        "/base_dir/parameters/#{region}/#{stack_name}.yml",
+      ]
+    )
+  end
+
   it 'has default and region specific parameter file locations' do
     expect(stack_definition.parameter_files).to eq([
+      "/base_dir/parameters/#{stack_name}.yaml",
       "/base_dir/parameters/#{stack_name}.yml",
-      "/base_dir/parameters/#{region}/#{stack_name}.yml"
+      "/base_dir/parameters/#{region}/#{stack_name}.yaml",
+      "/base_dir/parameters/#{region}/#{stack_name}.yml",
     ])
   end
 
   context 'with additional parameter lookup dirs' do
     before do
       stack_definition.send(:additional_parameter_lookup_dirs=, ['production'])
+      allow(Dir).to receive(:glob).with(
+        File.join(base_dir, 'parameters', "production", "#{stack_name}.y*ml")
+      ).and_return(
+        [
+          "/base_dir/parameters/production/#{stack_name}.yaml",
+          "/base_dir/parameters/production/#{stack_name}.yml",
+        ]
+      )
     end
 
     it 'includes a parameter lookup dir for it' do
       expect(stack_definition.parameter_files).to eq([
+        "/base_dir/parameters/#{stack_name}.yaml",
         "/base_dir/parameters/#{stack_name}.yml",
+        "/base_dir/parameters/#{region}/#{stack_name}.yaml",
         "/base_dir/parameters/#{region}/#{stack_name}.yml",
-        "/base_dir/parameters/production/#{stack_name}.yml"
+        "/base_dir/parameters/production/#{stack_name}.yaml",
+        "/base_dir/parameters/production/#{stack_name}.yml",
       ])
     end
   end