[aws|elasticache] implement modify_cache_parameter_group request

lib/fog/aws/elasticache.rb

@@ -19,7 +19,7 @@ module Fog
       request :create_cache_parameter_group
       request :delete_cache_parameter_group
       request :describe_cache_parameter_groups
-      #request :modify_cache_parameter_group
+      request :modify_cache_parameter_group
       #request :reset_cache_parameter_group
       request :describe_engine_default_parameters
       #request :describe_cache_parameters

lib/fog/aws/parsers/elasticache/modify_parameter_group.rb

@@ -0,0 +1,27 @@
+module Fog
+  module Parsers
+    module AWS
+      module Elasticache
+        require 'fog/aws/parsers/elasticache/parameter_group_parser'
+
+        class ModifyParameterGroup < ParameterGroupParser
+
+          def reset
+            super
+            @response['ModifyCacheParameterGroupResult'] = []
+          end
+
+          def end_element(name)
+            case name
+            when 'ModifyCacheParameterGroupResult'
+              @response[name] = @parameter_group
+              reset_parameter_group
+            else
+              super
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/fog/aws/requests/elasticache/modify_cache_parameter_group.rb

@@ -0,0 +1,45 @@
+module Fog
+  module AWS
+    class Elasticache
+      class Real
+
+        require 'fog/aws/parsers/elasticache/modify_parameter_group'
+
+        # Modifies an existing cache parameter group
+        # Returns a the name of the modified parameter group
+        #
+        # === Required Parameters
+        # * id <~String> - The ID of the parameter group to be modified
+        # * new_parameters <~Hash> - The parameters to modify, and their values
+        # === Returns
+        # * response <~Excon::Response>:
+        #   * body <~Hash>
+        def modify_cache_parameter_group(id, new_parameters)
+          # Construct Parameter Modifications in the format:
+          #   ParameterNameValues.member.N.ParameterName => "param_name"
+          #   ParameterNameValues.member.N.ParameterValue => "param_value"
+          n = 0   # n is the parameter index
+          parameter_changes = new_parameters.inject({}) do |new_args,pair|
+            n += 1
+            new_args["ParameterNameValues.member.#{n}.ParameterName"] = pair[0]
+            new_args["ParameterNameValues.member.#{n}.ParameterValue"] = pair[1]
+            new_args
+          end
+          # Merge the Cache Security Group parameters with the normal options
+          request(parameter_changes.merge(
+            'Action'                      => 'ModifyCacheParameterGroup',
+            'CacheParameterGroupName'     => id,
+            :parser => Fog::Parsers::AWS::Elasticache::ModifyParameterGroup.new
+          ))
+        end
+
+      end
+
+      class Mock
+        def modify_cache_parameter_group(id, new_parameters)
+          Fog::Mock.not_implemented
+        end
+      end
+    end
+  end
+end

tests/aws/requests/elasticache/helper.rb

@@ -24,7 +24,7 @@ class AWS
       }
       SINGLE_PARAMETER_GROUP = BASIC.merge('CacheParameterGroup' => PARAMETER_GROUP)
       DESCRIBE_PARAMETER_GROUPS = BASIC.merge('CacheParameterGroups' => [PARAMETER_GROUP])
-
+      MODIFY_PARAMETER_GROUP = {'CacheParameterGroupName' => String }
       ENGINE_DEFAULTS = {
         'CacheParameterGroupFamily'       => String,
         'Parameters'                      => Array,

tests/aws/requests/elasticache/parameter_group_tests.rb

@@ -49,6 +49,16 @@ Shindo.tests('AWS::Elasticache | parameter group requests', ['aws', 'elasticache
       body
     end
 
+    tests(
+    '#modify_cache_parameter_group'
+    ).formats('CacheParameterGroupName' => String) do
+      result = AWS[:elasticache].modify_cache_parameter_group(
+        name, {"chunk_size" => 32}
+      ).body['ModifyCacheParameterGroupResult']
+      returns(name) {result['CacheParameterGroupName']}
+      result
+    end
+
     tests(
     '#delete_cache_parameter_group'
     ).formats(AWS::Elasticache::Formats::BASIC) do