Allow dropping sidekiq jobs for a single queue

This allows dropping sidekiq jobs for the
`Namespaces::RootStatisticsWorker` when flipping the
`drop_duplicate_sidekiq_jobs_for_queue` feature flag.

lib/gitlab/sidekiq_middleware/duplicate_jobs.rb

@@ -5,8 +5,18 @@ require 'digest'
 module Gitlab
   module SidekiqMiddleware
     module DuplicateJobs
-      def self.drop_duplicates?
-        Feature.enabled?(:drop_duplicate_sidekiq_jobs)
+      DROPPABLE_QUEUES = Set.new([
+        Namespaces::RootStatisticsWorker.queue
+      ]).freeze
+
+      def self.drop_duplicates?(queue_name)
+        Feature.enabled?(:drop_duplicate_sidekiq_jobs) ||
+          drop_duplicates_for_queue?(queue_name)
+      end
+
+      private_class_method def self.drop_duplicates_for_queue?(queue_name)
+        DROPPABLE_QUEUES.include?(queue_name) &&
+          Feature.enabled?(:drop_duplicate_sidekiq_jobs_for_queue)
       end
     end
   end

lib/gitlab/sidekiq_middleware/duplicate_jobs/duplicate_job.rb

@@ -67,7 +67,7 @@ module Gitlab
         end
 
         def droppable?
-          idempotent? && duplicate? && DuplicateJobs.drop_duplicates?
+          idempotent? && duplicate? && DuplicateJobs.drop_duplicates?(queue_name)
         end
 
         private

spec/lib/gitlab/sidekiq_middleware/duplicate_jobs/duplicate_job_spec.rb

@@ -129,7 +129,8 @@ describe Gitlab::SidekiqMiddleware::DuplicateJobs::DuplicateJob, :clean_gitlab_r
       before do
         allow(AuthorizedProjectsWorker).to receive(:idempotent?).and_return(idempotent)
         allow(duplicate_job).to receive(:duplicate?).and_return(duplicate)
-        stub_feature_flags(drop_duplicate_sidekiq_jobs: feature_enabled)
+        allow(Gitlab::SidekiqMiddleware::DuplicateJobs)
+          .to receive(:drop_duplicates?).with(queue).and_return(feature_enabled)
       end
 
       it 'is droppable when all conditions are met' do

spec/lib/gitlab/sidekiq_middleware/duplicate_jobs_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::SidekiqMiddleware::DuplicateJobs do
+  using RSpec::Parameterized::TableSyntax
+
+  describe '.drop_duplicates?' do
+    where(:global_feature_enabled, :selected_queue_enabled, :queue, :expected) do
+      true  | true  | described_class::DROPPABLE_QUEUES.first | true
+      true  | true  | "other_queue"                           | true
+      true  | false | described_class::DROPPABLE_QUEUES.first | true
+      true  | false | "other_queue"                           | true
+      false | true  | described_class::DROPPABLE_QUEUES.first | true
+      false | true  | "other_queue"                           | false
+      false | false | described_class::DROPPABLE_QUEUES.first | false
+      false | false | "other_queue"                           | false
+    end
+
+    with_them do
+      before do
+        stub_feature_flags(drop_duplicate_sidekiq_jobs: global_feature_enabled,
+                           drop_duplicate_sidekiq_jobs_for_queue: selected_queue_enabled)
+      end
+
+      it "allows dropping jobs when expected" do
+        expect(described_class.drop_duplicates?(queue)).to be(expected)
+      end
+    end
+  end
+end