feat: add source_conditions method

Adds ability to specify WHERE-clause for select query from source tmp-table

Author: ZhidkovDenis

lib/redis_counters/dumpers/destination.rb

@@ -58,10 +58,18 @@ class Destination
       # Условия соеденяются через AND.
       attr_accessor :conditions
 
+      # Список дополнительных условий, которые применяются для выборки из source-таблицы для обновления
+      # target, Array of String.
+      # Каждое условие представляет собой строку - часть SQL выражения, которое может включать именованные
+      # параметры из числа доступных в хеше общих параметров дампера: engine.common_params.
+      # Условия соединяются через AND.
+      attr_accessor :source_conditions
+
       def initialize(engine)
         @engine = engine
         @fields_map = HashWithIndifferentAccess.new
         @conditions = []
+        @source_conditions = []
       end
 
       def merge
@@ -73,6 +81,7 @@ def merge
             (
               SELECT #{selected_fields_expression}
               FROM #{source_table}
+              #{source_conditions_expression}
               #{group_by_expression}
             ),
             updated AS
@@ -133,6 +142,12 @@ def extra_conditions
         result = conditions.map { |condition| "(#{condition})" }.join(' AND ')
         result.present? ? "AND #{result}" : result
       end
+
+      def source_conditions_expression
+        return if source_conditions.blank?
+
+        "WHERE #{source_conditions.map { |source_condition| "(#{source_condition})" }.join(' AND ')}"
+      end
     end
   end
 end

lib/redis_counters/dumpers/dsl/destination.rb

@@ -28,6 +28,10 @@ def map(field, target_field)
           def condition(value)
             destination.conditions << value
           end
+
+          def source_condition(value)
+            destination.source_conditions << value
+          end
         end
 
         module ClassMethods

spec/lib/redis_counters/dumpers/engine_spec.rb

@@ -93,5 +93,64 @@
     And { expect(StatsAggTotal.count).to eq 2 }
     And { expect(StatsAggTotal.where(record_id: 1).first.hits).to eq 6 }
     And { expect(StatsAggTotal.where(record_id: 2).first.hits).to eq 2 }
+
+    context 'with source conditions' do
+      let(:dumper) do
+        RedisCounters::Dumpers::Engine.build do
+          name :stats_totals
+          fields record_id: :integer,
+                 column_id: :integer,
+                 value: :integer,
+                 date: :date
+
+          destination do
+            model StatsByDay
+            take :record_id, :column_id, :hits, :date
+            key_fields :record_id, :column_id, :date
+            increment_fields :hits
+            map :hits, to: :value
+            condition 'target.date = :date'
+            source_condition 'column_id = 100'
+          end
+
+          destination do
+            model StatsTotal
+            take :record_id, :column_id, :hits
+            key_fields :record_id, :column_id
+            increment_fields :hits
+            map :hits, to: :value
+            source_condition 'column_id = 100'
+          end
+
+          destination do
+            model StatsAggTotal
+            take :record_id, :hits
+            key_fields :record_id
+            increment_fields :hits
+            map :hits, to: 'sum(value)'
+            group_by :record_id
+            source_condition 'column_id = 100'
+          end
+
+          on_before_merge do |dumper, _connection|
+            dumper.common_params = {date: dumper.date.strftime('%Y-%m-%d')}
+          end
+        end
+      end
+
+      Then { expect(StatsByDay.count).to eq 4 }
+      And { expect(StatsByDay.where(record_id: 1, column_id: 100, date: prev_date).first.hits).to eq 1 }
+      And { expect(StatsByDay.where(record_id: 2, column_id: 100, date: prev_date).first.hits).to eq 1 }
+      And { expect(StatsByDay.where(record_id: 1, column_id: 100, date: date).first.hits).to eq 1 }
+      And { expect(StatsByDay.where(record_id: 2, column_id: 100, date: date).first.hits).to eq 1 }
+
+      And { expect(StatsTotal.count).to eq 2 }
+      And { expect(StatsTotal.where(record_id: 1, column_id: 100).first.hits).to eq 2 }
+      And { expect(StatsTotal.where(record_id: 2, column_id: 100).first.hits).to eq 2 }
+
+      And { expect(StatsAggTotal.count).to eq 2 }
+      And { expect(StatsAggTotal.where(record_id: 1).first.hits).to eq 2 }
+      And { expect(StatsAggTotal.where(record_id: 2).first.hits).to eq 2 }
+    end
   end
 end