Log pipeline tags size

app/models/ci/pipeline.rb

@@ -466,6 +466,18 @@ module Ci
       statuses.count(:id)
     end
 
+    def tags_count
+      if tag_counts_enabled?
+        ActsAsTaggableOn::Tagging.where(taggable: builds).count
+      end
+    end
+
+    def distinct_tags_count
+      if tag_counts_enabled?
+        ActsAsTaggableOn::Tagging.where(taggable: builds).count('distinct(tag_id)')
+      end
+    end
+
     def stages_names
       statuses.order(:stage_idx).distinct
         .pluck(:stage, :stage_idx).map(&:first)
@@ -1340,6 +1352,12 @@ module Ci
       ::Gitlab::Ci::PipelineObjectHierarchy
         .new(self.class.unscoped.where(id: id), options: options)
     end
+
+    def tag_counts_enabled?
+      strong_memoize(:tag_counts_enabled) do
+        ::Feature.enabled?(:ci_pipeline_logger_tags_count, project, default_enabled: :yaml)
+      end
+    end
   end
 end
 

config/feature_flags/development/ci_pipeline_logger_tags_count.yml

+---
+name: ci_pipeline_logger_tags_count
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/77112
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/348967
+milestone: '14.7'
+type: development
+group: group::pipeline execution
+default_enabled: false

lib/gitlab/ci/pipeline/logger.rb

@@ -50,11 +50,21 @@ module Gitlab
             class: self.class.name.to_s,
             pipeline_creation_caller: caller,
             project_id: project.id,
-            pipeline_id: pipeline.id,
             pipeline_persisted: pipeline.persisted?,
             pipeline_source: pipeline.source,
             pipeline_creation_service_duration_s: age
-          }.stringify_keys.merge(observations_hash)
+          }
+
+          if pipeline.persisted?
+            attributes[:pipeline_builds_tags_count] = pipeline.tags_count
+            attributes[:pipeline_builds_distinct_tags_count] = pipeline.distinct_tags_count
+
+            attributes[:pipeline_id] = pipeline.id
+          end
+
+          attributes.compact!
+          attributes.stringify_keys!
+          attributes.merge!(observations_hash)
 
           destination.info(attributes)
         end

spec/models/ci/pipeline_spec.rb

@@ -4677,4 +4677,32 @@ RSpec.describe Ci::Pipeline, :mailer, factory_default: :keep do
     let!(:model) { create(:ci_pipeline, user: create(:user)) }
     let!(:parent) { model.user }
   end
+
+  describe 'tags count' do
+    let_it_be_with_refind(:pipeline) do
+      create(:ci_empty_pipeline, project: project)
+    end
+
+    it { expect(pipeline.tags_count).to eq(0) }
+    it { expect(pipeline.distinct_tags_count).to eq(0) }
+
+    context 'with builds' do
+      before do
+        create(:ci_build, pipeline: pipeline, tag_list: %w[a b])
+        create(:ci_build, pipeline: pipeline, tag_list: %w[b c])
+      end
+
+      it { expect(pipeline.tags_count).to eq(4) }
+      it { expect(pipeline.distinct_tags_count).to eq(3) }
+    end
+
+    context 'with the FF disabled' do
+      before do
+        stub_feature_flags(ci_pipeline_logger_tags_count: false)
+      end
+
+      it { expect(pipeline.tags_count).to be_nil }
+      it { expect(pipeline.distinct_tags_count).to be_nil }
+    end
+  end
 end

spec/services/ci/create_pipeline_service/logger_spec.rb

@@ -35,7 +35,9 @@ RSpec.describe Ci::CreatePipelineService do
         'pipeline_creation_service_duration_s' => a_kind_of(Numeric),
         'pipeline_creation_duration_s' => counters,
         'pipeline_size_count' => counters,
-        'pipeline_step_gitlab_ci_pipeline_chain_seed_duration_s' => counters
+        'pipeline_step_gitlab_ci_pipeline_chain_seed_duration_s' => counters,
+        'pipeline_builds_tags_count' => a_kind_of(Numeric),
+        'pipeline_builds_distinct_tags_count' => a_kind_of(Numeric)
       }
     end
 
@@ -81,7 +83,6 @@ RSpec.describe Ci::CreatePipelineService do
           {
             'pipeline_creation_caller' => 'Ci::CreatePipelineService',
             'pipeline_source' => 'push',
-            'pipeline_id' => nil,
             'pipeline_persisted' => false,
             'project_id' => project.id,
             'pipeline_creation_service_duration_s' => a_kind_of(Numeric),