[aws|elasticache] implement describe_engine_default_parameters request

lib/fog/aws/elasticache.rb

@@ -21,7 +21,7 @@ module Fog
       request :describe_cache_parameter_groups
       #request :modify_cache_parameter_group
       #request :reset_cache_parameter_group
-      #request :describe_engine_default_parameters
+      request :describe_engine_default_parameters
       #request :describe_cache_parameters
 
       request :create_cache_security_group

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

@@ -0,0 +1,22 @@
+module Fog
+  module Parsers
+    module AWS
+      module Elasticache
+        require 'fog/aws/parsers/elasticache/engine_defaults_parser'
+
+        class DescribeEngineDefaultParameters < EngineDefaultsParser
+
+          def end_element(name)
+            case name
+            when 'EngineDefaults'
+              @response[name] = @engine_defaults
+              reset_engine_defaults
+            else
+              super
+            end
+          end
+        end
+      end
+    end
+  end
+end

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

@@ -0,0 +1,59 @@
+module Fog
+  module Parsers
+    module AWS
+      module Elasticache
+        require 'fog/aws/parsers/elasticache/base'
+
+        class EngineDefaultsParser < Base
+
+          def reset
+            super
+            reset_engine_defaults
+          end
+
+          def reset_engine_defaults
+            @engine_defaults = {
+              'CacheNodeTypeSpecificParameters' => [],
+              'Parameters'                      => [],
+            }
+          end
+
+          def start_element(name, attrs = [])
+            case name
+            when 'CacheNodeTypeSpecificParameter', 'Parameter'
+              @parameter = {}
+            when 'CacheNodeTypeSpecificValues'
+              @parameter[name] = []
+            when 'CacheNodeTypeSpecificValue'
+              @node_specific_value = {}
+            else
+              super
+            end
+          end
+
+          def end_element(name)
+            case name
+            when 'CacheParameterGroupFamily'
+              @engine_defaults[name] = value
+            when 'CacheNodeTypeSpecificParameter', 'Parameter'
+              if not @parameter.empty?
+                @engine_defaults["#{name}s"] << @parameter
+              end
+            when 'AllowedValues', 'DataType', 'Description', 'IsModifiable',
+              'MinimumEngineVersion', 'ParameterName', 'Source'
+              @parameter[name] = value
+            when 'CacheNodeType', 'Value'
+              @node_specific_value[name] = value
+            when 'CacheNodeTypeSpecificValue'
+              if not @node_specific_value.empty?
+                @parameter["#{name}s"] << @node_specific_value
+              end
+            else
+              super
+            end
+          end
+        end
+      end
+    end
+  end
+end

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

@@ -0,0 +1,35 @@
+module Fog
+  module AWS
+    class Elasticache
+      class Real
+
+        require 'fog/aws/parsers/elasticache/describe_engine_default_parameters'
+
+        # Returns the default engine and system parameter information
+        # for the specified cache engine.
+        #
+        # === Parameters (optional)
+        # * options <~Hash>:
+        # *  :engine <~String> - the engine whose parameters are requested
+        # *  :marker <~String> - marker provided in the previous request
+        # *  :max_records <~Integer> - the maximum number of records to include
+        def describe_engine_default_parameters(options = {})
+          request({
+            'Action'                    => 'DescribeEngineDefaultParameters',
+            'CacheParameterGroupFamily' => options[:engine] || 'memcached1.4',
+            'Marker'                    => options[:marker],
+            'MaxRecords'                => options[:max_records],
+            :parser => Fog::Parsers::AWS::Elasticache::DescribeEngineDefaultParameters.new
+          })
+        end
+
+      end
+
+      class Mock
+        def describe_engine_defalut_parameters(options = {})
+          Fog::Mock.not_implemented
+        end
+      end
+    end
+  end
+end

tests/aws/requests/elasticache/helper.rb

@@ -25,6 +25,12 @@ class AWS
       SINGLE_PARAMETER_GROUP = BASIC.merge('CacheParameterGroup' => PARAMETER_GROUP)
       DESCRIBE_PARAMETER_GROUPS = BASIC.merge('CacheParameterGroups' => [PARAMETER_GROUP])
 
+      ENGINE_DEFAULTS = {
+        'CacheParameterGroupFamily'       => String,
+        'Parameters'                      => Array,
+        'CacheNodeTypeSpecificParameters' => Array,
+      }
+
       # Cache Clusters - more parameters get added as the lifecycle progresses
       CACHE_CLUSTER = {
         'AutoMinorVersionUpgrade'     => String,  # actually TrueClass or FalseClass

tests/aws/requests/elasticache/parameter_group_tests.rb

@@ -6,6 +6,15 @@ Shindo.tests('AWS::Elasticache | parameter group requests', ['aws', 'elasticache
     name = 'fog-test'
     description = 'Fog Test Parameter Group'
 
+    tests(
+    '#describe_engine_default_parameters'
+    ).formats(AWS::Elasticache::Formats::ENGINE_DEFAULTS) do
+      response = AWS[:elasticache].describe_engine_default_parameters
+      engine_defaults = response.body['EngineDefaults']
+      returns('memcached1.4') { engine_defaults['CacheParameterGroupFamily'] }
+      engine_defaults
+    end
+
     tests(
     '#create_cache_parameter_group'
     ).formats(AWS::Elasticache::Formats::SINGLE_PARAMETER_GROUP) do