[PATCH conductor 01/15] Add base classes and modules to support provider selection algorithms

ifarkas at redhat.com ifarkas at redhat.com
Sun Jul 22 10:16:21 UTC 2012


From: Imre Farkas <ifarkas at redhat.com>

---
 src/lib/provider_selection.rb                    |    4 +
 src/lib/provider_selection/base.rb               |   92 ++++++++++++++++++++++
 src/lib/provider_selection/chainable_strategy.rb |   16 ++++
 src/lib/provider_selection/match.rb              |   15 ++++
 src/lib/provider_selection/priority_group.rb     |   57 ++++++++++++++
 src/lib/provider_selection/rank.rb               |   19 +++++
 src/lib/provider_selection/strategy.rb           |   25 ++++++
 7 files changed, 228 insertions(+)
 create mode 100644 src/lib/provider_selection.rb
 create mode 100644 src/lib/provider_selection/base.rb
 create mode 100644 src/lib/provider_selection/chainable_strategy.rb
 create mode 100644 src/lib/provider_selection/match.rb
 create mode 100644 src/lib/provider_selection/priority_group.rb
 create mode 100644 src/lib/provider_selection/rank.rb
 create mode 100644 src/lib/provider_selection/strategy.rb

diff --git a/src/lib/provider_selection.rb b/src/lib/provider_selection.rb
new file mode 100644
index 0000000..eff3c25
--- /dev/null
+++ b/src/lib/provider_selection.rb
@@ -0,0 +1,4 @@
+# Require files in lib dir
+['match', 'priority_group', 'rank', 'strategy', 'base'].each do |file_name|
+  require File.join(File.dirname(__FILE__), 'provider_selection', file_name)
+end
diff --git a/src/lib/provider_selection/base.rb b/src/lib/provider_selection/base.rb
new file mode 100644
index 0000000..d2525fb
--- /dev/null
+++ b/src/lib/provider_selection/base.rb
@@ -0,0 +1,92 @@
+module ProviderSelection
+
+  class Base
+
+    @strategies = []
+    @view_paths = []
+
+    class << self
+      attr_reader :strategies
+      attr_reader :view_paths
+
+      def register_strategy(name, lib_path, options = {})
+        require lib_path
+        new_klass = "provider_selection/strategies/#{name.to_s}".classify.constantize
+        @strategies << Strategy.new(name, new_klass)
+      end
+
+      def find_strategy_by_name(name)
+        @strategies.detect{ |strategy| strategy.name == name }
+      end
+
+      def add_view_path(view_path)
+        @view_paths << view_path
+      end
+    end
+
+    attr_reader :instances
+
+    def initialize(instances)
+      @instances = instances
+      @strategy_chain = self
+    end
+
+    def calculate
+      rank = Rank.new(@instances)
+
+      provider_accounts = find_common_provider_accounts.map do |provider_account|
+        provider_account if provider_account.quota.can_start?(@instances)
+      end.uniq.compact
+
+      default_priority_group = PriorityGroup.new
+      rank.priority_groups << default_priority_group
+
+      provider_accounts.uniq.each do |provider_account|
+        default_priority_group.matches << Match.new(provider_account)
+      end
+
+      rank
+    end
+
+    def next_match
+      rank = @strategy_chain.calculate
+
+      rank.ordered_priority_groups.each do |priority_group|
+        random_match = priority_group.get_random_match
+        return random_match if random_match.present?
+      end
+
+      nil
+    end
+
+    def chain_strategy(name, options = {})
+      @strategy_chain = "provider_selection/strategies/#{name.to_s}".classify.constantize.new(@strategy_chain, options)
+    end
+
+    private
+
+    def find_common_provider_accounts
+      instance_matches_grouped_by_instances = @instances.map do |instance|
+        matches, errors = instance.matches
+        matches
+      end
+
+      result = []
+      if instance_matches_grouped_by_instances.any?
+          result += instance_matches_grouped_by_instances.first.map(&:provider_account)
+      end
+
+      instance_matches_grouped_by_instances.each_with_index do |instance_matches, index|
+        if index == 0
+          result += instance_matches.map(&:provider_account)
+        else
+          result &= instance_matches.map(&:provider_account)
+        end
+      end
+
+      result
+    end
+
+  end
+
+end
diff --git a/src/lib/provider_selection/chainable_strategy.rb b/src/lib/provider_selection/chainable_strategy.rb
new file mode 100644
index 0000000..12377de
--- /dev/null
+++ b/src/lib/provider_selection/chainable_strategy.rb
@@ -0,0 +1,16 @@
+module ProviderSelection
+
+  module ChainableStrategy
+
+    def initialize(strategies, options)
+      @strategies = strategies
+      @options = options
+    end
+
+    def method_missing(method, *args)
+      args.empty? ? @strategies.send(method) : @strategies.send(method, args)
+    end
+
+  end
+
+end
diff --git a/src/lib/provider_selection/match.rb b/src/lib/provider_selection/match.rb
new file mode 100644
index 0000000..5b4c5ed
--- /dev/null
+++ b/src/lib/provider_selection/match.rb
@@ -0,0 +1,15 @@
+module ProviderSelection
+
+  class Match
+
+    attr_accessor :score
+    attr_accessor :provider_account
+
+    def initialize(provider_account, score = nil)
+      @provider_account = provider_account
+      @score = score
+    end
+
+  end
+
+end
\ No newline at end of file
diff --git a/src/lib/provider_selection/priority_group.rb b/src/lib/provider_selection/priority_group.rb
new file mode 100644
index 0000000..c884ca2
--- /dev/null
+++ b/src/lib/provider_selection/priority_group.rb
@@ -0,0 +1,57 @@
+module ProviderSelection
+
+  class PriorityGroup
+
+    attr_accessor :matches
+    attr_accessor :score
+
+    def initialize(score = nil)
+      @matches = []
+      @score = score
+    end
+
+    def self.create_from_active_record(obj, allowed_provider_accounts)
+      return nil if allowed_provider_accounts.nil? || allowed_provider_accounts.empty?
+
+      priority_group = PriorityGroup.new(obj.score)
+
+      possible_provider_accounts = []
+      obj.provider_priority_group_elements.each do |element|
+        if element.value.is_a?(Provider)
+          possible_provider_accounts += element.value.provider_accounts
+        elsif element.value.is_a?(ProviderAccount)
+          possible_provider_accounts << element.value
+        end
+      end
+
+      possible_provider_accounts &= allowed_provider_accounts
+
+      return nil if possible_provider_accounts.empty?
+
+      possible_provider_accounts.each do |provider_account|
+        priority_group.matches << Match.new(provider_account)
+      end
+
+      priority_group
+    end
+
+    # TODO: extend the implementation to be able to work with negative scores
+    def get_random_match
+      # In order to work with 0 scores adding the size of the @matches array
+      match_sum_score = @matches.sum{ |match| match.score.to_i } + @matches.length
+      random_value = rand(match_sum_score)
+
+      sum = 0
+      matches.each_with_index do |match, index|
+        sum += match.score.to_i
+        if random_value < sum + index + 1
+          return match
+        end
+      end
+
+      nil
+    end
+
+  end
+
+end
diff --git a/src/lib/provider_selection/rank.rb b/src/lib/provider_selection/rank.rb
new file mode 100644
index 0000000..643dd71
--- /dev/null
+++ b/src/lib/provider_selection/rank.rb
@@ -0,0 +1,19 @@
+module ProviderSelection
+
+  class Rank
+
+    attr_accessor :priority_groups
+    attr_reader :instances
+
+    def initialize(instances)
+      @priority_groups = []
+      @instances = instances
+    end
+
+    def ordered_priority_groups
+      @priority_groups.sort_by{ |priority_group| priority_group.score.to_i }.reverse
+    end
+
+  end
+
+end
\ No newline at end of file
diff --git a/src/lib/provider_selection/strategy.rb b/src/lib/provider_selection/strategy.rb
new file mode 100644
index 0000000..4e0fa6a
--- /dev/null
+++ b/src/lib/provider_selection/strategy.rb
@@ -0,0 +1,25 @@
+module ProviderSelection
+
+  class Strategy
+
+    attr_reader :name
+    attr_reader :klass
+    attr_reader :include_in_listings
+
+    def initialize(name, klass)
+      @name = name
+      @klass = klass
+      @include_in_listing = if klass.respond_to?('include_in_listings?')
+        klass.include_in_listings?
+      else
+        true
+      end
+    end
+
+    def translated_name
+      I18n.t("strategies.#{@name}.name")
+    end
+
+  end
+
+end
\ No newline at end of file
-- 
1.7.10.4




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