feat: get evaluation get result (#88)

* feat: added-engine-function-signatures

* feat: moved-engine-to-core

* feat: implemented-process-segment-overrides

* feat: implemented-evalute-segments-partially

* feat: implemented-should-apply-override

* feat: implemented-get-identity-segments

* feat: implemented-new-in-and-fixed-remaining-tests

* feat: run-lint

* feat: misc

* feat: json-path-lib-implementation

* remove dup

* feat: made-legacy-functions-public

* feat: updated-tests-to-match-engine-in-operator-accepting-numbers

* feat: engine-agnostic-to-empty-identity-in-segment-evaluation

* feat: renamed-to-is-higher-priority

* feat: renamed-get-identity-segments-func

* feat: reverted-to-is-primitive

* feat: use-weakest-priority-constant

* feat: upgraded-engine-test-data-and-fixed-mv-evaluation-bug

* feat: removed-targeting-reason-func

* feat: linter-rubocop-autocorrect

* feat: linter

* feat: linter

* feat: moved-mappers-to-engine-namespace

* feat: enrich-context-with-identity-key

* feat: run-ci-on-all-branches

* feat: removed-comments

* feat!: sdk consumes context engine (#89)

* fix: sdk-uses-new-engine-methods

* feat: introduced-jsonpath-library

* feat: fixed-conflict

* Update lib/flagsmith/engine/segments/models.rb

Co-authored-by: Kim Gustyr <[email protected]>

* Update lib/flagsmith/engine/segments/models.rb

* feat: removed-normalize

* feat: linter

* feat: replaced-flagsmith-id-with-id

* feat: removed-comments

---------

Co-authored-by: Kim Gustyr <[email protected]>

---------

Co-authored-by: Gagan Trivedi <[email protected]>
Co-authored-by: Kim Gustyr <[email protected]>

Author: 3 people

.github/workflows/pull_request.yaml

@@ -14,9 +14,6 @@ on:
       - synchronize
       - reopened
       - ready_for_review
-    branches:
-      - main
-      - release/**
 
   push:
     branches:

Gemfile.lock

@@ -4,6 +4,7 @@ PATH
     flagsmith (4.3.0)
       faraday (>= 2.0.1)
       faraday-retry
+      jsonpath (~> 1.1)
       semantic
 
 GEM
@@ -21,8 +22,11 @@ GEM
       faraday (~> 2.0)
     gem-release (2.2.2)
     json (2.7.1)
+    jsonpath (1.1.5)
+      multi_json
     language_server-protocol (3.17.0.3)
     method_source (1.0.0)
+    multi_json (1.17.0)
     net-http (0.4.1)
       uri
     parallel (1.24.0)

flagsmith.gemspec

@@ -34,6 +34,7 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency 'faraday', '>= 2.0.1'
   spec.add_dependency 'faraday-retry'
+  spec.add_dependency 'jsonpath', '~> 1.1'
   spec.add_dependency 'semantic'
   spec.metadata['rubygems_mfa_required'] = 'true'
 end

lib/flagsmith.rb

@@ -69,7 +69,6 @@ def initialize(config)
       api_client
       analytics_processor
       environment_data_polling_manager
-      engine
       load_offline_handler
     end
 
@@ -99,10 +98,6 @@ def realtime_client
       @realtime_client ||= Flagsmith::RealtimeClient.new(@config)
     end
 
-    def engine
-      @engine ||= Flagsmith::Engine::Engine.new
-    end
-
     def analytics_processor
       return nil unless @config.enable_analytics?
 
@@ -211,21 +206,33 @@ def get_value_for_identity(feature_name, user_id = nil, default: nil)
     end
 
     def get_identity_segments(identifier, traits = {})
-      unless environment
-        raise Flagsmith::ClientError,
-              'Local evaluation or offline handler is required to obtain identity segments.'
-      end
+      raise Flagsmith::ClientError, 'Local evaluation or offline handler is required to obtain identity segments.' unless environment
 
       identity_model = get_identity_model(identifier, traits)
-      segment_models = engine.get_identity_segments(environment, identity_model)
-      segment_models.map { |sm| Flagsmith::Segments::Segment.new(id: sm.id, name: sm.name) }.compact
+      context = Flagsmith::Engine::Mappers.get_evaluation_context(environment, identity_model)
+      raise Flagsmith::ClientError, 'Local evaluation required to obtain identity segments' unless context
+
+      evaluation_result = Flagsmith::Engine.get_evaluation_result(context)
+      evaluation_result[:segments].filter_map do |segment_result|
+        id = segment_result.dig(:metadata, :id)
+        Flagsmith::Segments::Segment.new(id: id, name: segment_result[:name]) if id
+      end
     end
 
     private
 
-    def environment_flags_from_document
-      Flagsmith::Flags::Collection.from_feature_state_models(
-        engine.get_environment_feature_states(environment),
+    def environment_flags_from_document # rubocop:disable Metrics/MethodLength
+      context = Flagsmith::Engine::Mappers.get_evaluation_context(environment)
+
+      unless context
+        raise Flagsmith::ClientError,
+              'Unable to get flags. No environment present.'
+      end
+
+      evaluation_result = Flagsmith::Engine.get_evaluation_result(context)
+
+      Flagsmith::Flags::Collection.from_evaluation_result(
+        evaluation_result,
         analytics_processor: analytics_processor,
         default_flag_handler: default_flag_handler,
         offline_handler: offline_handler
@@ -234,12 +241,13 @@ def environment_flags_from_document
 
     def get_identity_flags_from_document(identifier, traits = {})
       identity_model = get_identity_model(identifier, traits)
+      context = Flagsmith::Engine::Mappers.get_evaluation_context(environment, identity_model)
+      raise Flagsmith::ClientError, 'Unable to get flags. No environment present.' unless context
 
-      Flagsmith::Flags::Collection.from_feature_state_models(
-        engine.get_identity_feature_states(environment, identity_model),
-        identity_id: identity_model.composite_key,
-        analytics_processor: analytics_processor,
-        default_flag_handler: default_flag_handler,
+      evaluation_result = Flagsmith::Engine.get_evaluation_result(context)
+      Flagsmith::Flags::Collection.from_evaluation_result(
+        evaluation_result,
+        analytics_processor: analytics_processor, default_flag_handler: default_flag_handler,
         offline_handler: offline_handler
       )
     end

lib/flagsmith/engine/core.rb

@@ -5,86 +5,143 @@
 
 require_relative 'environments/models'
 require_relative 'features/models'
+require_relative 'features/constants'
 require_relative 'identities/models'
 require_relative 'organisations/models'
 require_relative 'projects/models'
 require_relative 'segments/evaluator'
 require_relative 'segments/models'
 require_relative 'utils/hash_func'
 require_relative 'mappers'
-require_relative 'evaluation/core'
 
 module Flagsmith
+  # Core evaluation logic for feature flags
   module Engine
-    # Flags engine methods
-    class Engine
-      include Flagsmith::Engine::Segments::Evaluator
-
-      def get_identity_feature_state(environment, identity, feature_name, override_traits = nil)
-        feature_states = get_identity_feature_states_dict(environment, identity, override_traits).values
+    extend self
+    include Flagsmith::Engine::Utils::HashFunc
+    include Flagsmith::Engine::Features::TargetingReasons
+    include Flagsmith::Engine::Segments::Evaluator
+
+    # Get evaluation result from evaluation context
+    #
+    # @param evaluation_context [Hash] The evaluation context
+    # @return [Hash] Evaluation result with flags and segments
+    def get_evaluation_result(evaluation_context)
+      evaluation_context = get_enriched_context(evaluation_context)
+      segments, segment_overrides = evaluate_segments(evaluation_context)
+      flags = evaluate_features(evaluation_context, segment_overrides)
+      {
+        flags: flags,
+        segments: segments
+      }
+    end
 
-        feature_state = feature_states.find { |f| f.feature.name == feature_name }
+    # Returns { segments: EvaluationResultSegments; segmentOverrides: Record<string, SegmentOverride>; }
+    def evaluate_segments(evaluation_context)
+      return [], {} if evaluation_context[:segments].nil?
 
-        raise Flagsmith::FeatureStateNotFound, 'Feature State Not Found' if feature_state.nil?
+      identity_segments = get_segments_from_context(evaluation_context)
 
-        feature_state
+      segments = identity_segments.map do |segment|
+        { name: segment[:name], metadata: segment[:metadata] }.compact
       end
 
-      def get_identity_feature_states(environment, identity, override_traits = nil)
-        feature_states = get_identity_feature_states_dict(environment, identity, override_traits).values
+      segment_overrides = process_segment_overrides(identity_segments)
+
+      [segments, segment_overrides]
+    end
 
-        return feature_states.select(&:enabled?) if environment.project.hide_disabled_flags
+    # Returns Record<string: override.name, SegmentOverride>
+    def process_segment_overrides(identity_segments) # rubocop:disable Metrics/MethodLength
+      segment_overrides = {}
 
-        feature_states
+      identity_segments.each do |segment|
+        Array(segment[:overrides]).each do |override|
+          next unless should_apply_override(override, segment_overrides)
+
+          segment_overrides[override[:name]] = {
+            feature: override,
+            segment_name: segment[:name]
+          }
+        end
       end
 
-      def get_environment_feature_state(environment, feature_name)
-        features_state = environment.feature_states.find { |f| f.feature.name == feature_name }
+      segment_overrides
+    end
 
-        raise Flagsmith::FeatureStateNotFound, 'Feature State Not Found' if features_state.nil?
+    def evaluate_features(evaluation_context, segment_overrides)
+      identity_key = get_identity_key(evaluation_context)
 
-        features_state
+      (evaluation_context[:features] || {}).each_with_object({}) do |(_, feature), flags|
+        segment_override = segment_overrides[feature[:name]]
+        final_feature = segment_override ? segment_override[:feature] : feature
+
+        flag_result = build_flag_result(final_feature, identity_key, segment_override)
+        flags[final_feature[:name].to_sym] = flag_result
       end
+    end
 
-      def get_environment_feature_states(environment)
-        return environment.feature_states.select(&:enabled?) if environment.project.hide_disabled_flags
+    # Returns {value: any; reason?: string}
+    def evaluate_feature_value(feature, identity_key = nil)
+      return get_multivariate_feature_value(feature, identity_key) if feature[:variants]&.any? && identity_key
 
-        environment.feature_states
-      end
+      { value: feature[:value], reason: nil }
+    end
 
-      private
+    # Returns {value: any; reason?: string}
+    def get_multivariate_feature_value(feature, identity_key)
+      percentage_value = hashed_percentage_for_object_ids([feature[:key], identity_key])
+      sorted_variants = (feature[:variants] || []).sort_by { |v| v[:priority] || WEAKEST_PRIORITY }
 
-      def get_identity_feature_states_dict(environment, identity, override_traits = nil)
-        # Get feature states from the environment
-        feature_states = {}
-        override = ->(fs) { feature_states[fs.feature.id] = fs }
-        environment.feature_states.each(&override)
+      variant = find_matching_variant(sorted_variants, percentage_value)
+      variant || { value: feature[:value], reason: nil }
+    end
 
-        override_by_matching_segments(environment, identity, override_traits) do |fs|
-          override.call(fs) unless higher_segment_priority?(feature_states, fs)
-        end
+    def find_matching_variant(sorted_variants, percentage_value)
+      start_percentage = 0
+      sorted_variants.each do |variant|
+        limit = start_percentage + variant[:weight]
+        return { value: variant[:value], reason: "#{TARGETING_REASON_SPLIT}; weight=#{variant[:weight]}" } if start_percentage <= percentage_value && percentage_value < limit
 
-        # Override with any feature states defined directly the identity
-        identity.identity_features.each(&override)
-        feature_states
+        start_percentage = limit
       end
+      nil
+    end
 
-      # Override with any feature states defined by matching segments
-      def override_by_matching_segments(environment, identity, override_traits)
-        identity_segments = get_identity_segments(environment, identity, override_traits)
-        identity_segments.each do |matching_segment|
-          matching_segment.feature_states.each do |feature_state|
-            yield feature_state if block_given?
-          end
-        end
-      end
+    # returns boolean
+    def should_apply_override(override, existing_overrides)
+      current_override = existing_overrides[override[:name]]
+      !current_override || stronger_priority?(override[:priority], current_override[:feature][:priority])
+    end
 
-      def higher_segment_priority?(collection, feature_state)
-        collection.key?(feature_state.feature.id) &&
-          collection[feature_state.feature.id].higher_segment_priority?(
-            feature_state
-          )
-      end
+    private
+
+    def build_flag_result(feature, identity_key, segment_override)
+      evaluated = evaluate_feature_value(feature, identity_key)
+
+      flag_result = {
+        name: feature[:name],
+        enabled: feature[:enabled],
+        value: evaluated[:value],
+        reason: evaluated[:reason] || (segment_override ? "#{TARGETING_REASON_TARGETING_MATCH}; segment=#{segment_override[:segment_name]}" : TARGETING_REASON_DEFAULT)
+      }
+
+      flag_result[:metadata] = feature[:metadata] if feature[:metadata]
+      flag_result
+    end
+
+    # Extract identity key from evaluation context
+    #
+    # @param evaluation_context [Hash] The evaluation context
+    # @return [String, nil] The identity key or nil if no identity
+    def get_identity_key(evaluation_context)
+      return nil unless evaluation_context[:identity]
+
+      evaluation_context[:identity][:key]
+    end
+
+    def stronger_priority?(priority_a, priority_b)
+      (priority_a || WEAKEST_PRIORITY) < (priority_b || WEAKEST_PRIORITY)
     end
   end
 end