Add code and spec for overriding elements within a hash

Author: Kevin Paulisse

lib/octocatalog-diff/catalog-util/enc.rb

@@ -5,6 +5,7 @@
 require_relative 'enc/script'
 
 require 'stringio'
+require 'yaml'
 
 module OctocatalogDiff
   module CatalogUtil
@@ -46,6 +47,36 @@ def error_message
 
       private
 
+      # Override of ENC parameters with parameters specified on the command line.
+      # Modifies structures in @enc_obj.
+      # @param logger [Logger] Logger object
+      def override_enc_parameters(_logger)
+        return unless @options[:enc_override].is_a?(Array) && @options[:enc_override].any?
+        content_structure = YAML.load(@content)
+        @options[:enc_override].each { |x| merge_enc_param(x.key, x.value) }
+        @content = content_structure.to_yaml
+      end
+
+      # Merging behavior for ENC overrides
+      # @param pointer [Hash] Portion of the content structure to modify
+      # @param key [String] String representing structure, delimited by '::'
+      # @param value [?] Value to insert at structure point
+      def merge_enc_param(pointer, key, value)
+        if key =~ /::/
+          first_key, the_rest = key.split(/::/, 2)
+          if pointer[first_key].nil?
+            pointer[first_key] = {}
+          elsif !pointer[first_key].is_a?(Hash)
+            raise ArgumentError, "Attempt to override #{pointer[first_key].class} with hash for #{key}"
+          end
+          merge_enc_param(pointer[first_key], the_rest, value)
+        elsif value.nil?
+          pointer.delete(key)
+        else
+          pointer[key] = value
+        end
+      end
+
       # Backend - given options, choose an appropriate backend and construct the corresponding object.
       # @return [?] Backend object
       def backend
@@ -72,6 +103,7 @@ def execute(logger = nil)
         logger ||= @options[:logger]
         logger ||= Logger.new(StringIO.new)
         @enc_obj.execute(logger) if @enc_obj.respond_to?(:execute)
+        override_enc_parameters(logger)
         @executed = true
       end
     end

spec/octocatalog-diff/tests/catalog-util/enc_spec.rb

@@ -126,4 +126,100 @@
       end
     end
   end
+
+  describe '#merge_enc_param' do
+    before(:each) do
+      @logger, @logger_str = OctocatalogDiff::Spec.setup_logger
+      @subject = described_class.allocate
+    end
+
+    it 'should replace a parameter at the top level' do
+      struct = {
+        'parameters' => {
+          'foo' => 'bar',
+          'baz' => 'fuzz'
+        }
+      }
+      @subject.send(:merge_enc_param, struct, 'parameters', 'baz4')
+      expect(struct['parameters']).to eq('baz4')
+    end
+
+    it 'should add a parameter at the top level' do
+      struct = {
+        'parameters' => {
+          'foo' => 'bar',
+          'baz' => 'fuzz'
+        }
+      }
+      @subject.send(:merge_enc_param, struct, 'stuffs', 'baz4')
+      expect(struct['stuffs']).to eq('baz4')
+    end
+
+    it 'should remove a parameter at the top level' do
+      struct = {
+        'parameters' => {
+          'foo' => 'bar',
+          'baz' => 'fuzz'
+        }
+      }
+      @subject.send(:merge_enc_param, struct, 'parameters', nil)
+      expect(struct).to eq({})
+    end
+
+    it 'should error if breaking the structure' do
+      struct = {
+        'parameters' => {
+          'foo' => 'bar',
+          'baz' => 'fuzz'
+        }
+      }
+      expect do
+        @subject.send(:merge_enc_param, struct, 'parameters::foo::baz3', 'baz4')
+      end.to raise_error(ArgumentError, /Attempt to override String with hash for foo::baz3/)
+    end
+
+    it 'should overwrite a key nested in a hash with same datatype' do
+      struct = {
+        'parameters' => {
+          'foo' => 'bar',
+          'baz' => 'fuzz'
+        }
+      }
+      @subject.send(:merge_enc_param, struct, 'parameters::foo', 'baz4')
+      expect(struct['parameters']['foo']).to eq('baz4')
+    end
+
+    it 'should overwrite a key nested in a hash with different datatype' do
+      struct = {
+        'parameters' => {
+          'foo' => 'bar',
+          'baz' => 'fuzz'
+        }
+      }
+      @subject.send(:merge_enc_param, struct, 'parameters::foo', %w(kittens puppies))
+      expect(struct['parameters']['foo']).to eq(%w(kittens puppies))
+    end
+
+    it 'should delete a key nested in a hash' do
+      struct = {
+        'parameters' => {
+          'foo' => 'bar',
+          'baz' => 'fuzz'
+        }
+      }
+      @subject.send(:merge_enc_param, struct, 'parameters::foo', nil)
+      expect(struct['parameters'].key?('foo')).to eq(false)
+    end
+
+    it 'should overwrite a key nested deeply in a hash with same datatype' do
+      struct = {
+        'parameters' => {
+          'foo' => { 'bar' => { 'baz' => 'chicken' } },
+          'baz' => 'fuzz'
+        }
+      }
+      @subject.send(:merge_enc_param, struct, 'parameters::foo::bar::baz', 'turkey')
+      expect(struct['parameters']['foo']['bar']['baz']).to eq('turkey')
+    end
+  end
 end