Calculate Metering Used Hours only from used hours

app/models/chargeback/consumption_with_rollups.rb

@@ -63,6 +63,10 @@ def chargeback_fields_present
       @chargeback_fields_present ||= @rollups.count(&:chargeback_fields_present?)
     end
 
+    def metering_used_fields_present
+      @metering_used_fields_present ||= @rollups.count(&:metering_used_fields_present?)
+    end
+
     private
 
     def born_at

app/models/chargeback/consumption_without_rollups.rb

@@ -41,6 +41,10 @@ def chargeback_fields_present
       1 # Yes, charge this interval as fixed_compute_*_*
     end
 
+    def metering_used_fields_present
+      0 # we don't count used hours in metering report
+    end
+
     def current_value(metric, _sub_metric = nil)
       # Return the last seen allocation for charging purposes.
       @value ||= {}

app/models/metering.rb

@@ -1,7 +1,7 @@
 module Metering
   def calculate_costs(consumption, _)
     self.fixed_compute_metric = consumption.chargeback_fields_present if consumption.chargeback_fields_present
-    self.metering_used_metric = fixed_compute_metric
+    self.metering_used_metric = consumption.metering_used_fields_present if consumption.metering_used_fields_present
     self.existence_hours_metric = consumption.consumed_hours_in_interval
 
     relevant_fields.each do |field|

app/models/metric_rollup.rb

@@ -8,6 +8,8 @@ class MetricRollup < ApplicationRecord
                                 net_usage_rate_average derived_vm_used_disk_storage
                                 derived_vm_allocated_disk_storage).freeze
 
+  METERING_USED_METRIC_FIELDS = %w(cpu_usagemhz_rate_average derived_memory_used net_usage_rate_average).freeze
+
   CAPTURE_INTERVAL_NAMES = %w(hourly daily).freeze
 
   #
@@ -70,4 +72,8 @@ def chargeback_fields_present?
 
     @chargeback_fields_present = CHARGEBACK_METRIC_FIELDS.any? { |field| send(field).present? && send(field).nonzero? }
   end
+
+  def metering_used_fields_present?
+    @metering_used_fields_present ||= METERING_USED_METRIC_FIELDS.any? { |field| send(field).present? && send(field).nonzero? }
+  end
 end

spec/models/metering_vm_spec.rb

@@ -77,5 +77,25 @@
       expect(subject.storage_allocated_metric).to eq(derived_vm_allocated_disk_storage)
       expect(subject.storage_used_metric).to eq(derived_vm_used_disk_storage * count_of_metric_rollup)
     end
+
+    context 'count of used hours is different than count of metric rollups' do
+      let(:used_metric_attributtes_with_zeros) do
+        # create hash with metrics as keys with zeros in values
+        # e.g. {"cpu_usagemhz_rate_average"=>0, "derived_memory_used"=>0, ...
+        Hash[MetricRollup::METERING_USED_METRIC_FIELDS.inject([]) { |result_array, metric| result_array << [metric, 0] }]
+      end
+
+      let(:count_of_metric_rollup_with_zero_used_metric) { 20 }
+
+      before do
+        vm.metric_rollups.limit(20).each { |record| record.update(used_metric_attributtes_with_zeros) }
+      end
+
+      it 'calculates metering used hours only from used metrics' do
+        expect(subject.metering_used_metric).to eq(vm.metric_rollups.count - count_of_metric_rollup_with_zero_used_metric)
+        expect(subject.metering_used_metric).to eq(40)
+        expect(subject.metering_used_metric).not_to eq(subject.fixed_compute_metric)
+      end
+    end
   end
 end