1 files changed, 95 insertions, 0 deletions
diff --git a/app/services/ci/test_failure_history_service.rb b/app/services/ci/test_failure_history_service.rb
new file mode 100644
index 00000000000..99a2592ec06
--- /dev/null
+++ b/app/services/ci/test_failure_history_service.rb
@@ -0,0 +1,95 @@
+# frozen_string_literal: true
+
+module Ci
+  class TestFailureHistoryService
+    class Async
+      attr_reader :service
+
+      def initialize(service)
+        @service = service
+      end
+
+      def perform_if_needed
+        TestFailureHistoryWorker.perform_async(service.pipeline.id) if service.should_track_failures?
+      end
+    end
+
+    MAX_TRACKABLE_FAILURES = 200
+
+    attr_reader :pipeline
+    delegate :project, to: :pipeline
+
+    def initialize(pipeline)
+      @pipeline = pipeline
+    end
+
+    def execute
+      return unless should_track_failures?
+
+      track_failures
+    end
+
+    def should_track_failures?
+      return false unless Feature.enabled?(:test_failure_history, project)
+      return false unless project.default_branch_or_master == pipeline.ref
+
+      # We fetch for up to MAX_TRACKABLE_FAILURES + 1 builds. So if ever we get
+      # 201 total number of builds with the assumption that each job has at least
+      # 1 failed test case, then we have at least 201 failed test cases which exceeds
+      # the MAX_TRACKABLE_FAILURES of 200. If this is the case, let's early exit so we
+      # don't have to parse each JUnit report of each of the 201 builds.
+      failed_builds.length <= MAX_TRACKABLE_FAILURES
+    end
+
+    def async
+      Async.new(self)
+    end
+
+    private
+
+    def failed_builds
+      @failed_builds ||= pipeline.builds_with_failed_tests(limit: MAX_TRACKABLE_FAILURES + 1)
+    end
+
+    def track_failures
+      failed_test_cases = gather_failed_test_cases(failed_builds)
+
+      return if failed_test_cases.size > MAX_TRACKABLE_FAILURES
+
+      failed_test_cases.keys.each_slice(100) do |key_hashes|
+        Ci::TestCase.transaction do
+          ci_test_cases = Ci::TestCase.find_or_create_by_batch(project, key_hashes)
+          failures = test_case_failures(ci_test_cases, failed_test_cases)
+
+          Ci::TestCaseFailure.insert_all(failures)
+        end
+      end
+    end
+
+    def gather_failed_test_cases(failed_builds)
+      failed_builds.each_with_object({}) do |build, failed_test_cases|
+        test_suite = generate_test_suite!(build)
+        test_suite.failed.keys.each do |key|
+          failed_test_cases[key] = build
+        end
+      end
+    end
+
+    def generate_test_suite!(build)
+      # Returns an instance of Gitlab::Ci::Reports::TestSuite
+      build.collect_test_reports!(Gitlab::Ci::Reports::TestReports.new)
+    end
+
+    def test_case_failures(ci_test_cases, failed_test_cases)
+      ci_test_cases.map do |test_case|
+        build = failed_test_cases[test_case.key_hash]
+
+        {
+          test_case_id: test_case.id,
+          build_id: build.id,
+          failed_at: build.finished_at
+        }
+      end
+    end
+  end
+end