feature/EYPP-1211: simple, target and step policies support for asg

Author: starbeast

lib/fog/aws.rb

@@ -87,6 +87,113 @@ module AWS
     service(:sts,             'STS')
     service(:support,         'Support')
 
+    # Transforms hash keys according to the passed mapping or given block
+    #
+    # ==== Parameters
+    # * object<~Hash> - A hash to apply transformation to
+    # * mappings<~Hash> - A hash of mappings for keys. Keys of the mappings object should match desired keys of the
+    #   object which will be transformed. If object contains values that are hashes or arrays of hashes which should
+    #   be transformed as well mappings object's value should be configured with a specific form, for example:
+    #   {
+    #     :key => {
+    #       'Key' => {
+    #         :nested_key => 'NestedKey'
+    #       }
+    #     }
+    #   }
+    #   This form will transform object's key :key to 'Key'
+    #   and transform corresponding value: if it's a hash then its key :nested_key will be transformed into 'NestedKey'
+    #   if it's an array of hashes, each hash element of the array will have it's key :nested_key transformed into 'NestedKey'
+    # * block<~Proc> - block which is applied if mappings object does not contain key. Block receives key as it's argument
+    #   and should return new key as the one that will be used to replace the original one
+    # ==== Returns
+    # * object<~Hash> - hash containing transformed keys
+    #
+    def self.map_keys(object, mappings = nil, &block)
+      case object
+      when ::Hash
+        object.reduce({}) do |acc, (key, val)|
+          mapping = mappings[key] if mappings
+          new_key, new_value = begin
+            if mapping
+              case mapping
+              when ::Hash
+                mapped_key = mapping.keys[0]
+                [mapped_key, map_keys(val, mapping[mapped_key], &block)]
+              else
+                [mapping, map_keys(val, &block)]
+              end
+            else
+              mapped_value = map_keys(val, &block)
+              if block_given?
+                [block.call(key), mapped_value]
+              else
+                [key, mapped_value]
+              end
+            end
+          end
+          acc[new_key] = new_value
+          acc
+        end
+      when ::Array
+        object.map { |item| map_keys(item, mappings, &block) }
+      else
+        object
+      end
+    end
+
+    # Maps object keys to aws compatible: underscore keys are transformed in camel case strings
+    # with capitalized first word (aka :ab_cd transforms into AbCd). Already compatible keys remain the same
+    #
+    # ==== Parameters
+    # * object<~Hash> - A hash to apply transformation to
+    # * mappings<~Hash> - An optional hash of mappings for keys
+    # ==== Returns
+    # * object<~Hash> - hash containing transformed keys
+    #
+    def self.map_to_aws(object, mappings = nil)
+      map_keys(object, mappings) do |key|
+        words = key.to_s.split('_')
+        if words.length > 1
+          words.collect(&:capitalize).join
+        else
+          words[0].split(/(?=[A-Z])/).collect(&:capitalize).join
+        end
+      end
+    end
+
+    # Maps object keys from aws to ruby compatible form aka snake case symbols
+    #
+    # ==== Parameters
+    # * object<~Hash> - A hash to apply transformation to
+    # * mappings<~Hash> - An optional hash of mappings for keys
+    # ==== Returns
+    # * object<~Hash> - hash containing transformed keys
+    #
+    def self.map_from_aws(object, mappings = nil)
+      map_keys(object, mappings) { |key| key.to_s.split(/(?=[A-Z])/).join('_').downcase.to_sym }
+    end
+
+    # Helper function to invert mappings: recursively replaces mapping keys and values.
+    #
+    # ==== Parameters
+    # * mappings<~Hash> - mappings hash
+    # ==== Returns
+    # * object<~Hash> - inverted mappings
+    #
+    def self.invert_mappings(mappings)
+      mappings.reduce({}) do |acc, (key, val)|
+        mapped_key, mapped_value = case val
+                                   when ::Hash
+                                     [val.keys[0], val.values[0]]
+                                   else
+                                     [val, nil]
+                                   end
+        acc[mapped_key] = mapped_value ? { key => invert_mappings(mapped_value) } : key
+        acc
+      end
+    end
+
     def self.indexed_param(key, values)
       params = {}
       unless key.include?('%d')

lib/fog/aws/models/auto_scaling/group.rb

@@ -99,6 +99,10 @@ def enable_metrics_collection(granularity = '1Minute', metrics = {})
           reload
         end
 
+        def policies
+          service.policies.all('AutoScalingGroupName' => id)
+        end
+
         def instances
           Fog::AWS::AutoScaling::Instances.new(:service => service).load(attributes[:instances])
         end

lib/fog/aws/models/auto_scaling/policy.rb

@@ -2,34 +2,103 @@ module Fog
   module AWS
     class AutoScaling
       class Policy < Fog::Model
-        identity :id,                       :aliases => 'PolicyName'
-        attribute :arn,                     :aliases => 'PolicyARN'
-        attribute :adjustment_type,         :aliases => 'AdjustmentType'
-        attribute :alarms,                  :aliases => 'Alarms'
-        attribute :auto_scaling_group_name, :aliases => 'AutoScalingGroupName'
-        attribute :cooldown,                :aliases => 'Cooldown'
-        attribute :min_adjustment_step,     :aliases => 'MinAdjustmentStep'
-        attribute :scaling_adjustment,      :aliases => 'ScalingAdjustment'
+        identity :id,                             :aliases => 'PolicyName'
+        attribute :arn,                           :aliases => 'PolicyARN'
+        attribute :type,                          :aliases => 'PolicyType'
+        attribute :adjustment_type,               :aliases => 'AdjustmentType'
+        attribute :scaling_adjustment,            :aliases => 'ScalingAdjustment'
+        attribute :step_adjustments,              :aliases => 'StepAdjustments'
+        attribute :target_tracking_configuration, :aliases => 'TargetTrackingConfiguration'
+        attribute :alarms,                        :aliases => 'Alarms'
+        attribute :auto_scaling_group_name,       :aliases => 'AutoScalingGroupName'
+        attribute :cooldown,                      :aliases => 'Cooldown'
+        attribute :estimated_instance_warmup,     :aliases => 'EstimatedInstanceWarmup'
+        attribute :metric_aggregation_type,       :aliases => 'MetricAggregationType'
+        attribute :min_adjustment_magnitude,      :aliases => 'MinAdjustmentMagnitude'
+        attribute :min_adjustment_step,           :aliases => 'MinAdjustmentStep'
+
+        STEP_ADJUSTMENTS_MAPPING = {
+          :metric_interval_lower_bound => 'MetricIntervalLowerBound',
+          :metric_interval_upper_bound => 'MetricIntervalUpperBound',
+          :scaling_adjustment          => 'ScalingAdjustment'
+        }.freeze
+
+        TARGET_TRACKING_MAPPING = {
+          :customized_metric_specification => {
+            'CustomizedMetricSpecification' => {
+              :metric_name => 'MetricName',
+              :namespace   => 'Namespace',
+              :statistics  => 'Statistics',
+              :unit        => 'Unit',
+              :dimensions  => {
+                'Dimensions' => {
+                  :name  => 'Name',
+                  :value => 'Value'
+                }
+              }
+            }
+          },
+          :disable_scale_in                => 'DisableScaleIn',
+          :target_value                    => 'TargetValue',
+          :predefined_metric_specification => {
+            'PredefinedMetricSpecification' => {
+              :predefined_metric_type => 'PredefinedMetricType',
+              :resource_label         => 'ResourceLabel'
+            }
+          }
+        }.freeze
+
+        # Returns attribute names specific for different policy types
+        #
+        # ==== Parameters
+        # * policy_type<~String> - type of the auto scaling policy
+        #
+        # ==== Returns
+        # * options<~Array> Array of string containing policy specific options
+        #
+        def self.preserve_options(policy_type)
+          case policy_type
+          when 'StepScaling'
+            %w(EstimatedInstanceWarmup PolicyType MinAdjustmentMagnitude MetricAggregationType AdjustmentType StepAdjustments)
+          when 'TargetTrackingScaling'
+            %w(EstimatedInstanceWarmup PolicyType TargetTrackingConfiguration)
+          else
+            %w(AdjustmentType ScalingAdjustment PolicyType Cooldown MinAdjustmentMagnitude MinAdjustmentStep)
+          end
+        end
 
         def initialize(attributes)
-          attributes['AdjustmentType']    ||= 'ChangeInCapacity'
-          attributes['ScalingAdjustment'] ||= 1
           super
+          case self.type
+          when 'StepScaling'
+            prepare_step_policy
+          when 'TargetTrackingScaling'
+            prepare_target_policy
+          else
+            prepare_simple_policy
+          end
         end
 
         # TODO: implement #alarms
-        # TODO: implement #auto_scaling_group
+
+        def auto_scaling_group
+          service.groups.get(self.auto_scaling_group_name)
+        end
 
         def save
-          requires :id
-          requires :adjustment_type
-          requires :auto_scaling_group_name
-          requires :scaling_adjustment
+          type_requirements
 
           options = Hash[self.class.aliases.map { |key, value| [key, send(value)] }]
-          options.delete_if { |key, value| value.nil? }
+          if options['TargetTrackingConfiguration']
+            options['TargetTrackingConfiguration'] = Fog::AWS.map_to_aws(options['TargetTrackingConfiguration'], TARGET_TRACKING_MAPPING)
+          end
+          if options['StepAdjustments']
+            options['StepAdjustments'] = Fog::AWS.map_to_aws(options['StepAdjustments'], STEP_ADJUSTMENTS_MAPPING)
+          end
+          options_keys = self.class.preserve_options(self.type)
+          options.delete_if { |key, value| value.nil? || !options_keys.include?(key) }
 
-          service.put_scaling_policy(adjustment_type, auto_scaling_group_name, id, scaling_adjustment, options)
+          service.put_scaling_policy(auto_scaling_group_name, id, options)
           reload
         end
 
@@ -38,6 +107,41 @@ def destroy
           requires :auto_scaling_group_name
           service.delete_policy(auto_scaling_group_name, id)
         end
+
+        private
+
+        def prepare_simple_policy
+          self.adjustment_type    ||= 'ChangeInCapacity'
+          self.scaling_adjustment ||= 1
+        end
+
+        def prepare_target_policy
+          # do we need default tracking configuration or should we just allow it to fail?
+          if target_tracking_configuration
+            self.target_tracking_configuration = Fog::AWS.map_from_aws(target_tracking_configuration, TARGET_TRACKING_MAPPING)
+          end
+        end
+
+        def prepare_step_policy
+          # do we need any default scaling steps or should we just allow it to fail?
+          self.adjustment_type ||= 'ChangeInCapacity'
+          if step_adjustments
+            self.step_adjustments = Fog::AWS.map_from_aws(step_adjustments, STEP_ADJUSTMENTS_MAPPING)
+          end
+        end
+
+        def type_requirements
+          requires :id
+          requires :auto_scaling_group_name
+          case self.type
+          when 'StepScaling'
+            requires :step_adjustments
+          when 'TargetTrackingScaling'
+            requires :target_tracking_configuration
+          else
+            requires :scaling_adjustment
+          end
+        end
       end
     end
   end