[PATCH conductor 01/15] Add base classes and modules to support provider selection algorithms
Jozef Zigmund
jzigmund at redhat.com
Thu Aug 2 02:17:21 UTC 2012
On Sun, 2012-07-22 at 12:16 +0200, ifarkas at redhat.com wrote:
> 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
^ this can be potentially security hole, where the loaded lib can get
access to the whole environment. For now, put here TODO with notice of security issue
> + 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
Please consider using 'require' in a method. Also I'm
not sure, but I think that RH Copyright's text should be applied on
those lib files.
--
Jozef Zigmund
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