Remove dead code ElasticBatchProjectIndexerWorker

This worker was first added in
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/1144 in %"8.17" but
all usages were removed in
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/13437 in %"12.0" .
Given that the usages of this worker have been removed for at least 1
major release now we should be safe to remove this worker itself. In
fact we could have removed it already in %"13.0" .

changelogs/unreleased/remove-dead-elasticsearch-indexing-code.yml

+---
+title: Remove dead Elasticsearch indexing code
+merge_request: 35936
+author:
+type: other

config/sidekiq_queues.yml

@@ -78,8 +78,6 @@
   - 1
 - - detect_repository_languages
   - 1
-- - elastic_batch_project_indexer
-  - 1
 - - elastic_commit_indexer
   - 1
 - - elastic_delete_project

db/migrate/20200706005325_remove_elastic_batch_project_indexer_worker_queue.rb

+# frozen_string_literal: true
+
+class RemoveElasticBatchProjectIndexerWorkerQueue < ActiveRecord::Migration[6.0]
+  DOWNTIME = false
+
+  def up
+    Sidekiq.redis do |conn|
+      conn.del "queue:elastic_batch_project_indexer"
+    end
+  end
+end

db/structure.sql

@@ -23541,5 +23541,6 @@ COPY "schema_migrations" (version) FROM STDIN;
 20200626130220
 20200702123805
 20200703154822
+20200706005325
 \.
 

ee/app/workers/all_queues.yml

@@ -571,14 +571,6 @@
   :weight: 2
   :idempotent: 
   :tags: []
-- :name: elastic_batch_project_indexer
-  :feature_category: :global_search
-  :has_external_dependencies: 
-  :urgency: :low
-  :resource_boundary: :unknown
-  :weight: 1
-  :idempotent: 
-  :tags: []
 - :name: elastic_commit_indexer
   :feature_category: :global_search
   :has_external_dependencies: 

ee/app/workers/elastic_batch_project_indexer_worker.rb

-# frozen_string_literal: true
-
-class ElasticBatchProjectIndexerWorker # rubocop:disable Scalability/IdempotentWorker
-  include ApplicationWorker
-
-  feature_category :global_search
-
-  # Batch indexing is a generally a onetime option, so give finer control over
-  # queuing and concurrency
-
-  # This worker is long-running, but idempotent, so retry many times if
-  # necessary
-  sidekiq_options retry: 10
-
-  def perform(start, finish)
-    projects = build_relation(start, finish)
-
-    projects.find_each { |project| run_indexer(project) }
-  end
-
-  private
-
-  def run_indexer(project)
-    return unless project.use_elasticsearch?
-
-    # Ensure we remove the hold on the project, no matter what, so ElasticCommitIndexerWorker can do its thing
-    # We do this before the indexer starts to avoid the possibility of pushes coming in during this time not
-    # being indexed.
-    Gitlab::Redis::SharedState.with { |redis| redis.srem(:elastic_projects_indexing, project.id) }
-
-    logger.info "Indexing #{project.full_name} (ID=#{project.id})..."
-
-    Gitlab::Elastic::Indexer.new(project).run
-
-    logger.info "Indexing #{project.full_name} (ID=#{project.id}) is done!"
-  rescue => err
-    logger.warn("#{err.message} indexing #{project.full_name} (ID=#{project.id}), trace - #{err.backtrace}")
-  end
-
-  # rubocop: disable CodeReuse/ActiveRecord
-  def build_relation(start, finish)
-    relation = Project.includes(:index_status)
-
-    table = Project.arel_table
-    relation = relation.where(table[:id].gteq(start)) if start
-    relation = relation.where(table[:id].lteq(finish)) if finish
-
-    relation
-  end
-  # rubocop: enable CodeReuse/ActiveRecord
-end

ee/spec/workers/elastic_batch_project_indexer_worker_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe ElasticBatchProjectIndexerWorker do
-  subject(:worker) { described_class.new }
-
-  let(:projects) { create_list(:project, 2) }
-
-  describe '#perform' do
-    before do
-      stub_ee_application_setting(elasticsearch_indexing: true)
-    end
-
-    context 'with elasticsearch only enabled for a particular project' do
-      before do
-        stub_ee_application_setting(elasticsearch_limit_indexing: true)
-        create :elasticsearch_indexed_project, project: projects.first
-      end
-
-      it 'only indexes the enabled project' do
-        projects.each { |project| expect_index(project).and_call_original }
-
-        expect(Gitlab::Elastic::Indexer).to receive(:new).with(projects.first).and_return(double(run: true))
-        expect(Gitlab::Elastic::Indexer).not_to receive(:new).with(projects.last)
-
-        worker.perform(projects.first.id, projects.last.id)
-      end
-    end
-
-    it 'runs the indexer for projects in the batch range' do
-      projects.each { |project| expect_index(project) }
-
-      worker.perform(projects.first.id, projects.last.id)
-    end
-
-    it 'skips projects not in the batch range' do
-      expect_index(projects.first).never
-      expect_index(projects.last)
-
-      worker.perform(projects.last.id, projects.last.id)
-    end
-
-    it 'clears the "locked" state from redis when the project finishes indexing' do
-      Gitlab::Redis::SharedState.with { |redis| redis.sadd(:elastic_projects_indexing, projects.first.id) }
-
-      expect_index(projects.first).and_call_original
-      expect_next_instance_of(Gitlab::Elastic::Indexer) do |indexer|
-        expect(indexer).to receive(:run)
-      end
-
-      expect { worker.perform(projects.first.id, projects.first.id) }
-        .to change { project_locked?(projects.first) }.from(true).to(false)
-    end
-
-    it 'reindexes projects that were already indexed' do
-      expect_index(projects.first)
-      expect_index(projects.last)
-
-      worker.perform(projects.first.id, projects.last.id)
-    end
-
-    it 'indexes all projects it receives even if already indexed', :sidekiq_might_not_need_inline do
-      expect_index(projects.first).and_call_original
-      expect_next_instance_of(Gitlab::Elastic::Indexer) do |indexer|
-        expect(indexer).to receive(:run)
-      end
-
-      worker.perform(projects.first.id, projects.first.id)
-    end
-  end
-
-  def expect_index(project)
-    expect(worker).to receive(:run_indexer).with(project)
-  end
-
-  def project_locked?(project)
-    Gitlab::Redis::SharedState.with { |redis| redis.sismember(:elastic_projects_indexing, project.id) }
-  end
-end