Added matcher

lib/splitclient-rb.rb

@@ -99,6 +99,7 @@
 require 'splitclient-rb/engine/matchers/between_semver_matcher'
 require 'splitclient-rb/engine/matchers/in_list_semver_matcher'
 require 'splitclient-rb/engine/matchers/rule_based_segment_matcher'
+require 'splitclient-rb/engine/matchers/prerequisites_matcher'
 require 'splitclient-rb/engine/evaluator/splitter'
 require 'splitclient-rb/engine/impressions/noop_unique_keys_tracker'
 require 'splitclient-rb/engine/impressions/unique_keys_tracker'

lib/splitclient-rb/engine/matchers/prerequisites_matcher.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module SplitIoClient
+  class PrerequisitesMatcher
+    def initialize(prerequisites, logger)
+      @prerequisites = prerequisites
+      @logger = logger
+    end
+
+    def match?(args)
+      keys = { matching_key: args[:matching_key], bucketing_key: args[:bucketing_key] }
+
+      match = true
+      @prerequisites.each do |prerequisite|
+        evaluate = args[:evaluator].evaluate_feature_flag(keys, prerequisite[:n], args[:attributes])
+        next if prerequisite[:ts].include?(evaluate[:treatment])
+
+        @logger.log_if_debug("[PrerequisitesMatcher] feature flag #{prerequisite[:n]} evaluated to #{evaluate[:treatment]} \
+          that does not exist in prerequisited treatments.")
+        match = false
+        break
+      end
+
+      match
+    end
+
+    def string_type?
+      false
+    end
+  end
+end

lib/splitclient-rb/helpers/repository_helper.rb

@@ -13,7 +13,7 @@ def self.update_feature_flag_repository(feature_flag_repository, feature_flags,
             next
           end
 
-          feature_flag = check_impressions_disabled(feature_flag, config)
+          feature_flag = check_missing_elements(feature_flag, config)
 
           config.logger.debug("storing feature flag (#{feature_flag[:name]})") if config.debug_enabled
           to_add.push(feature_flag)
@@ -22,13 +22,21 @@ def self.update_feature_flag_repository(feature_flag_repository, feature_flags,
         feature_flag_repository.update(to_add, to_delete, change_number)
       end
 
-      def self.check_impressions_disabled(feature_flag, config)
+      def self.check_missing_elements(feature_flag, config)
         unless feature_flag.key?(:impressionsDisabled)
           feature_flag[:impressionsDisabled] = false
           if config.debug_enabled
             config.logger.debug("feature flag (#{feature_flag[:name]}) does not have impressionsDisabled field, setting it to false")
           end
         end
+
+        unless feature_flag.key?(:prerequisites)
+          feature_flag[:prerequisites] = []
+          if config.debug_enabled
+            config.logger.debug("feature flag (#{feature_flag[:name]}) does not have prerequisites field, setting it to empty array")
+          end
+        end
+
         feature_flag
       end
 

spec/engine/matchers/prerequisites_matcher_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe SplitIoClient::PrerequisitesMatcher do
+  let(:evaluator) { double }
+
+  it 'matches with empty prerequisites' do
+    expect(described_class.new([], @split_logger)
+          .match?(matching_key: 'foo', bucketing_key: 'bar', evaluator: evaluator)).to eq(true)
+  end
+
+  it 'matches with prerequisite treatments' do
+    allow(evaluator).to receive(:evaluate_feature_flag).with({ matching_key: 'foo', bucketing_key: 'bar' }, 'flag1', nil)
+                                      .and_return(treatment: 'on')
+
+    expect(described_class.new([:n => 'flag1', :ts => ['on']], @split_logger)
+          .match?(matching_key: 'foo', bucketing_key: 'bar', evaluator: evaluator)).to eq(true)
+    expect(described_class.new([:n => 'flag1', :ts => ['off']], @split_logger)
+          .match?(matching_key: 'foo', bucketing_key: 'bar', evaluator: evaluator)).to eq(false)
+  end
+
+  it 'is not string type matcher' do
+    expect(described_class.new([], @split_logger).string_type?).to be false
+  end
+end

spec/repository_helper.rb

@@ -83,5 +83,21 @@
       expect(feature_flag_repository.get_split('split2').nil?).to eq(false)
       expect(feature_flag_repository.get_split('split1').nil?).to eq(true)
     end
+
+    it 'test prerequisites element' do
+      config = SplitIoClient::SplitConfig.new(cache_adapter: :memory)
+      flag_set_filter = SplitIoClient::Cache::Filter::FlagSetsFilter.new([])
+      flag_sets_repository = SplitIoClient::Cache::Repositories::MemoryFlagSetsRepository.new([])
+      feature_flag_repository = SplitIoClient::Cache::Repositories::SplitsRepository.new(
+        config,
+        flag_sets_repository,
+        flag_set_filter)
+
+      SplitIoClient::Helpers::RepositoryHelper.update_feature_flag_repository(feature_flag_repository, [{:name => 'split1', :status =>  'ACTIVE', conditions: [], :sets =>  []}], -1, config, false)
+      expect(feature_flag_repository.get_split('split1')[:prerequisites]).to eq([])
+
+      SplitIoClient::Helpers::RepositoryHelper.update_feature_flag_repository(feature_flag_repository, [{:name => 'split2', :status =>  'ACTIVE', conditions: [], :prerequisites => [{:n => 'flag', :ts => ['on']}], :sets =>  []}], -1, config, false)
+      expect(feature_flag_repository.get_split('split2')[:prerequisites]).to eq([{:n => 'flag', :ts => ['on']}])
+    end
   end
 end