Add alternative way of importing notes to GitHub Importer

app/workers/gitlab/github_import/stage/import_issues_and_diff_notes_worker.rb

@@ -12,17 +12,10 @@ module Gitlab
         include GithubImport::Queue
         include StageMethods
 
-        # The importers to run in this stage. Issues can't be imported earlier
-        # on as we also use these to enrich pull requests with assigned labels.
-        IMPORTERS = [
-          Importer::IssuesImporter,
-          Importer::DiffNotesImporter
-        ].freeze
-
         # client - An instance of Gitlab::GithubImport::Client.
         # project - An instance of Project.
         def import(client, project)
-          waiters = IMPORTERS.each_with_object({}) do |klass, hash|
+          waiters = importers(project).each_with_object({}) do |klass, hash|
             info(project.id, message: "starting importer", importer: klass.name)
             waiter = klass.new(project, client).execute
             hash[waiter.key] = waiter.jobs_remaining
@@ -30,6 +23,25 @@ module Gitlab
 
           AdvanceStageWorker.perform_async(project.id, waiters, :notes)
         end
+
+        # The importers to run in this stage. Issues can't be imported earlier
+        # on as we also use these to enrich pull requests with assigned labels.
+        def importers(project)
+          [
+            Importer::IssuesImporter,
+            diff_notes_importer(project)
+          ]
+        end
+
+        private
+
+        def diff_notes_importer(project)
+          if project.group.present? && Feature.enabled?(:github_importer_single_endpoint_notes_import, project.group, type: :ops, default_enabled: :yaml)
+            Importer::SingleEndpointDiffNotesImporter
+          else
+            Importer::DiffNotesImporter
+          end
+        end
       end
     end
   end

app/workers/gitlab/github_import/stage/import_notes_worker.rb

@@ -15,17 +15,31 @@ module Gitlab
         # client - An instance of Gitlab::GithubImport::Client.
         # project - An instance of Project.
         def import(client, project)
-          info(project.id, message: "starting importer", importer: 'Importer::NotesImporter')
-          waiter = Importer::NotesImporter
-            .new(project, client)
-            .execute
+          waiters = importers(project).each_with_object({}) do |klass, hash|
+            info(project.id, message: "starting importer", importer: klass.name)
+            waiter = klass.new(project, client).execute
+            hash[waiter.key] = waiter.jobs_remaining
+          end
 
           AdvanceStageWorker.perform_async(
             project.id,
-            { waiter.key => waiter.jobs_remaining },
+            waiters,
             :lfs_objects
           )
         end
+
+        def importers(project)
+          if project.group.present? && Feature.enabled?(:github_importer_single_endpoint_notes_import, project.group, type: :ops, default_enabled: :yaml)
+            [
+              Importer::SingleEndpointMergeRequestNotesImporter,
+              Importer::SingleEndpointIssueNotesImporter
+            ]
+          else
+            [
+              Importer::NotesImporter
+            ]
+          end
+        end
       end
     end
   end

config/feature_flags/ops/github_importer_lower_per_page_limit.yml

+---
+name: github_importer_lower_per_page_limit
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/67150
+rollout_issue_url:
+milestone: '14.2'
+type: ops
+group: group::import
+default_enabled: false

config/feature_flags/ops/github_importer_single_endpoint_notes_import.yml

+---
+name: github_importer_single_endpoint_notes_import
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/67150
+rollout_issue_url:
+milestone: '14.2'
+type: ops
+group: group::import
+default_enabled: false

doc/development/github_importer.md

@@ -272,3 +272,11 @@ The last log entry reports the number of objects fetched and imported:
   "import_stage": "Gitlab::GithubImport::Stage::FinishImportWorker"
 }
 ```
+
+## Errors when importing large projects
+
+The GitHub importer may encounter errors when importing large projects. For help with this, see the
+documentation for the following use cases:
+
+- [Alternative way to import notes and diff notes](../user/project/import/github.md#alternative-way-to-import-notes-and-diff-notes)
+- [Reduce GitHub API request objects per page](../user/project/import/github.md#reduce-github-api-request-objects-per-page)

doc/user/project/import/github.md

@@ -184,3 +184,51 @@ servers. For 4 servers with 8 cores this means you can import up to 32 objects (
 Reducing the time spent in cloning a repository can be done by increasing network throughput, CPU capacity, and disk
 performance (by using high performance SSDs, for example) of the disks that store the Git repositories (for your GitLab instance).
 Increasing the number of Sidekiq workers will *not* reduce the time spent cloning repositories.
+
+## Alternative way to import notes and diff notes
+
+When GitHub Importer runs on extremely large projects not all notes & diff notes can be imported due to GitHub API `issues_comments` & `pull_requests_comments` endpoints limitation.
+Not all pages can be fetched due to the following error coming from GitHub API: `In order to keep the API fast for everyone, pagination is limited for this resource. Check the rel=last link relation in the Link response header to see how far back you can traverse.`.
+
+Because of that, alternative approach for importing notes & diff notes is available that is behind a feature flag.
+
+Instead of using `issues_comments` & `pull_requests_comments`, use individual resources `issue_comments` & `pull_request_comments` instead in order to pull notes from 1 object at a time.
+This allows us to carry over any missing comments, however it increases the number of network requests required to perform the import, which means its execution is going to be much longer.
+
+In order to use alternative way of importing notes `github_importer_single_endpoint_notes_import` feature flag needs to be enabled on the group project is being imported into.
+
+Start a [Rails console](../../../administration/operations/rails_console.md#starting-a-rails-console-session).
+
+```ruby
+group = Group.find_by_full_path('my/group/fullpath')
+
+# Enable
+Feature.enable(:github_importer_single_endpoint_notes_import, group)
+
+# Disable
+Feature.disable(:github_importer_single_endpoint_notes_import, group)
+```
+
+## Reduce GitHub API request objects per page
+
+Some GitHub API endpoints may return a 500 or 502 error for project imports from large repositories.
+To reduce the chance of such errors, you can enable the feature flag
+`github_importer_lower_per_page_limit` in the group project importing the data. This reduces the
+page size from 100 to 50.
+
+To enable this feature flag, start a [Rails console](../../../administration/operations/rails_console.md#starting-a-rails-console-session)
+and run the following `enable` command:
+
+```ruby
+group = Group.find_by_full_path('my/group/fullpath')
+
+# Enable
+Feature.enable(:github_importer_lower_per_page_limit, group)
+```
+
+To disable the feature, run this command:
+
+```ruby
+# Disable
+Feature.disable(:github_importer_lower_per_page_limit, group)
+```

lib/gitlab/cache/import/caching.rb

@@ -7,6 +7,8 @@ module Gitlab
         # The default timeout of the cache keys.
         TIMEOUT = 24.hours.to_i
 
+        LONGER_TIMEOUT = 72.hours.to_i
+
         WRITE_IF_GREATER_SCRIPT = <<-EOF.strip_heredoc.freeze
         local key, value, ttl = KEYS[1], tonumber(ARGV[1]), ARGV[2]
         local existing = tonumber(redis.call("get", key))

lib/gitlab/github_import.rb

@@ -11,6 +11,7 @@ module Gitlab
       Client.new(
         token_to_use,
         host: host.presence || self.formatted_import_url(project),
+        per_page: self.per_page(project),
         parallel: parallel
       )
     end
@@ -33,5 +34,13 @@ module Gitlab
         url.to_s
       end
     end
+
+    def self.per_page(project)
+      if project.group.present? && Feature.enabled?(:github_importer_lower_per_page_limit, project.group, type: :ops, default_enabled: :yaml)
+        Gitlab::GithubImport::Client::LOWER_PER_PAGE
+      else
+        Gitlab::GithubImport::Client::DEFAULT_PER_PAGE
+      end
+    end
   end
 end

lib/gitlab/github_import/client.rb

@@ -19,6 +19,8 @@ module Gitlab
       attr_reader :octokit
 
       SEARCH_MAX_REQUESTS_PER_MINUTE = 30
+      DEFAULT_PER_PAGE = 100
+      LOWER_PER_PAGE = 50
 
       # A single page of data and the corresponding page number.
       Page = Struct.new(:objects, :number)
@@ -44,7 +46,7 @@ module Gitlab
       #            this value to `true` for parallel importing is crucial as
       #            otherwise hitting the rate limit will result in a thread
       #            being blocked in a `sleep()` call for up to an hour.
-      def initialize(token, host: nil, per_page: 100, parallel: true)
+      def initialize(token, host: nil, per_page: DEFAULT_PER_PAGE, parallel: true)
         @host = host
         @octokit = ::Octokit::Client.new(
           access_token: token,

lib/gitlab/github_import/importer/single_endpoint_diff_notes_importer.rb

+# frozen_string_literal: true
+
+# This importer is used when `github_importer_single_endpoint_notes_import`
+# feature flag is on and replaces `DiffNotesImporter`.
+#
+# It fetches 1 PR's diff notes at a time using `pull_request_comments` endpoint, which is
+# slower than `NotesImporter` but it makes sure all notes are imported,
+# as it can sometimes not be the case for `NotesImporter`, because
+# `issues_comments` endpoint it uses can be limited by GitHub API
+# to not return all available pages.
+module Gitlab
+  module GithubImport
+    module Importer
+      class SingleEndpointDiffNotesImporter
+        include ParallelScheduling
+        include SingleEndpointNotesImporting
+
+        def importer_class
+          DiffNoteImporter
+        end
+
+        def representation_class
+          Representation::DiffNote
+        end
+
+        def sidekiq_worker_class
+          ImportDiffNoteWorker
+        end
+
+        def object_type
+          :diff_note
+        end
+
+        def collection_method
+          :pull_request_comments
+        end
+
+        private
+
+        def noteables
+          project.merge_requests.where.not(iid: already_imported_noteables) # rubocop: disable CodeReuse/ActiveRecord
+        end
+
+        def page_counter_id(merge_request)
+          "merge_request/#{merge_request.id}/#{collection_method}"
+        end
+
+        def notes_imported_cache_key
+          "github-importer/merge_request/diff_notes/already-imported/#{project.id}"
+        end
+      end
+    end
+  end
+end

lib/gitlab/github_import/importer/single_endpoint_issue_notes_importer.rb

+# frozen_string_literal: true
+
+# This importer is used when `github_importer_single_endpoint_notes_import`
+# feature flag is on and replaces `IssuesImporter` issue notes import.
+#
+# It fetches 1 issue's comments at a time using `issue_comments` endpoint, which is
+# slower than `NotesImporter` but it makes sure all notes are imported,
+# as it can sometimes not be the case for `NotesImporter`, because
+# `issues_comments` endpoint it uses can be limited by GitHub API
+# to not return all available pages.
+module Gitlab
+  module GithubImport
+    module Importer
+      class SingleEndpointIssueNotesImporter
+        include ParallelScheduling
+        include SingleEndpointNotesImporting
+
+        def importer_class
+          NoteImporter
+        end
+
+        def representation_class
+          Representation::Note
+        end
+
+        def sidekiq_worker_class
+          ImportNoteWorker
+        end
+
+        def object_type
+          :note
+        end
+
+        def collection_method
+          :issue_comments
+        end
+
+        private
+
+        def noteables
+          project.issues.where.not(iid: already_imported_noteables) # rubocop: disable CodeReuse/ActiveRecord
+        end
+
+        def page_counter_id(issue)
+          "issue/#{issue.id}/#{collection_method}"
+        end
+
+        def notes_imported_cache_key
+          "github-importer/issue/notes/already-imported/#{project.id}"
+        end
+      end
+    end
+  end
+end

lib/gitlab/github_import/importer/single_endpoint_merge_request_notes_importer.rb

+# frozen_string_literal: true
+
+# This importer is used when `github_importer_single_endpoint_notes_import`
+# feature flag is on and replaces `NotesImporter` MR notes import.
+#
+# It fetches 1 PR's comments at a time using `issue_comments` endpoint, which is
+# slower than `NotesImporter` but it makes sure all notes are imported,
+# as it can sometimes not be the case for `NotesImporter`, because
+# `issues_comments` endpoint it uses can be limited by GitHub API
+# to not return all available pages.
+module Gitlab
+  module GithubImport
+    module Importer
+      class SingleEndpointMergeRequestNotesImporter
+        include ParallelScheduling
+        include SingleEndpointNotesImporting
+
+        def importer_class
+          NoteImporter
+        end
+
+        def representation_class
+          Representation::Note
+        end
+
+        def sidekiq_worker_class
+          ImportNoteWorker
+        end
+
+        def object_type
+          :note
+        end
+
+        def collection_method
+          :issue_comments
+        end
+
+        private
+
+        def noteables
+          project.merge_requests.where.not(iid: already_imported_noteables) # rubocop: disable CodeReuse/ActiveRecord
+        end
+
+        def page_counter_id(merge_request)
+          "merge_request/#{merge_request.id}/#{collection_method}"
+        end
+
+        def notes_imported_cache_key
+          "github-importer/merge_request/notes/already-imported/#{project.id}"
+        end
+      end
+    end
+  end
+end

lib/gitlab/github_import/issuable_finder.rb

@@ -23,7 +23,7 @@ module Gitlab
       #
       # This method will return `nil` if no ID could be found.
       def database_id
-        val = Gitlab::Cache::Import::Caching.read(cache_key)
+        val = Gitlab::Cache::Import::Caching.read(cache_key, timeout: timeout)
 
         val.to_i if val.present?
       end
@@ -32,7 +32,7 @@ module Gitlab
       #
       # database_id - The ID of the corresponding database row.
       def cache_database_id(database_id)
-        Gitlab::Cache::Import::Caching.write(cache_key, database_id)
+        Gitlab::Cache::Import::Caching.write(cache_key, database_id, timeout: timeout)
       end
 
       private
@@ -76,6 +76,14 @@ module Gitlab
           )
         end
       end
+
+      def timeout
+        if project.group.present? && ::Feature.enabled?(:github_importer_single_endpoint_notes_import, project.group, type: :ops, default_enabled: :yaml)
+          Gitlab::Cache::Import::Caching::LONGER_TIMEOUT
+        else
+          Gitlab::Cache::Import::Caching::TIMEOUT
+        end
+      end
     end
   end
 end

lib/gitlab/github_import/single_endpoint_notes_importing.rb

+# frozen_string_literal: true
+
+# This module is used in:
+#  - SingleEndpointDiffNotesImporter
+#  - SingleEndpointIssueNotesImporter
+#  - SingleEndpointMergeRequestNotesImporter
+#
+# `github_importer_single_endpoint_notes_import`
+# feature flag is on.
+#
+# It fetches 1 PR's associated objects at a time using `issue_comments` or
+# `pull_request_comments` endpoint, which is slower than `NotesImporter`
+# but it makes sure all notes are imported, as it can sometimes not be
+# the case for `NotesImporter`, because `issues_comments` endpoint
+# it uses can be limited by GitHub API to not return all available pages.
+module Gitlab
+  module GithubImport
+    module SingleEndpointNotesImporting
+      BATCH_SIZE = 100
+
+      def each_object_to_import
+        each_notes_page do |page|
+          page.objects.each do |note|
+            next if already_imported?(note)
+
+            Gitlab::GithubImport::ObjectCounter.increment(project, object_type, :fetched)
+
+            yield(note)
+
+            mark_as_imported(note)
+          end
+        end
+      end
+
+      def id_for_already_imported_cache(note)
+        note.id
+      end
+
+      private
+
+      def each_notes_page
+        noteables.each_batch(of: BATCH_SIZE, column: :iid) do |batch|
+          batch.each do |noteable|
+            # The page counter needs to be scoped by noteable to avoid skipping
+            # pages of notes from already imported noteables.
+            page_counter = PageCounter.new(project, page_counter_id(noteable))
+            repo = project.import_source
+            options = collection_options.merge(page: page_counter.current)
+
+            client.each_page(collection_method, repo, noteable.iid, options) do |page|
+              next unless page_counter.set(page.number)
+
+              yield page
+            end
+
+            mark_notes_imported(noteable)
+          end
+        end
+      end
+
+      def mark_notes_imported(noteable)
+        Gitlab::Cache::Import::Caching.set_add(
+          notes_imported_cache_key,
+          noteable.iid
+        )
+      end
+
+      def already_imported_noteables
+        Gitlab::Cache::Import::Caching.values_from_set(notes_imported_cache_key)
+      end
+
+      def noteables
+        NotImplementedError
+      end
+
+      def notes_imported_cache_key
+        NotImplementedError
+      end
+
+      def page_counter_id(noteable)
+        NotImplementedError
+      end
+    end
+  end
+end

spec/lib/gitlab/github_import/importer/single_endpoint_diff_notes_importer_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::GithubImport::Importer::SingleEndpointDiffNotesImporter do
+  let(:client) { double }
+  let(:project) { create(:project, import_source: 'github/repo') }
+
+  subject { described_class.new(project, client) }
+
+  it { is_expected.to include_module(Gitlab::GithubImport::ParallelScheduling) }
+  it { is_expected.to include_module(Gitlab::GithubImport::SingleEndpointNotesImporting) }
+  it { expect(subject.representation_class).to eq(Gitlab::GithubImport::Representation::DiffNote) }
+  it { expect(subject.importer_class).to eq(Gitlab::GithubImport::Importer::DiffNoteImporter) }
+  it { expect(subject.collection_method).to eq(:pull_request_comments) }
+  it { expect(subject.object_type).to eq(:diff_note) }
+  it { expect(subject.id_for_already_imported_cache(double(id: 1))).to eq(1) }
+
+  describe '#each_object_to_import', :clean_gitlab_redis_cache do
+    let(:merge_request) do
+      create(
+        :merged_merge_request,
+        iid: 999,
+        source_project: project,
+        target_project: project
+      )
+    end
+
+    let(:note) { double(id: 1) }
+    let(:page) { double(objects: [note], number: 1) }
+
+    it 'fetches data' do
+      expect(client)
+        .to receive(:each_page)
+        .exactly(:once) # ensure to be cached on the second call
+        .with(:pull_request_comments, 'github/repo', merge_request.iid, page: 1)
+        .and_yield(page)
+
+      expect { |b| subject.each_object_to_import(&b) }.to yield_with_args(note)
+
+      subject.each_object_to_import {}
+
+      expect(
+        Gitlab::Cache::Import::Caching.set_includes?(
+          "github-importer/merge_request/diff_notes/already-imported/#{project.id}",
+          merge_request.iid
+        )
+      ).to eq(true)
+    end
+
+    it 'skips cached pages' do
+      Gitlab::GithubImport::PageCounter
+        .new(project, "merge_request/#{merge_request.id}/pull_request_comments")
+        .set(2)
+
+      expect(client)
+        .to receive(:each_page)
+        .exactly(:once) # ensure to be cached on the second call
+        .with(:pull_request_comments, 'github/repo', merge_request.iid, page: 2)
+
+      subject.each_object_to_import {}
+    end
+
+    it 'skips cached merge requests' do
+      Gitlab::Cache::Import::Caching.set_add(
+        "github-importer/merge_request/diff_notes/already-imported/#{project.id}",
+        merge_request.iid
+      )
+
+      expect(client).not_to receive(:each_page)
+
+      subject.each_object_to_import {}
+    end
+  end
+end

spec/lib/gitlab/github_import/importer/single_endpoint_issue_notes_importer_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::GithubImport::Importer::SingleEndpointIssueNotesImporter do
+  let(:client) { double }
+  let(:project) { create(:project, import_source: 'github/repo') }
+
+  subject { described_class.new(project, client) }
+
+  it { is_expected.to include_module(Gitlab::GithubImport::ParallelScheduling) }
+  it { is_expected.to include_module(Gitlab::GithubImport::SingleEndpointNotesImporting) }
+  it { expect(subject.representation_class).to eq(Gitlab::GithubImport::Representation::Note) }
+  it { expect(subject.importer_class).to eq(Gitlab::GithubImport::Importer::NoteImporter) }
+  it { expect(subject.collection_method).to eq(:issue_comments) }
+  it { expect(subject.object_type).to eq(:note) }
+  it { expect(subject.id_for_already_imported_cache(double(id: 1))).to eq(1) }
+
+  describe '#each_object_to_import', :clean_gitlab_redis_cache do
+    let(:issue) do
+      create(
+        :issue,
+        iid: 999,
+        project: project
+      )
+    end
+
+    let(:note) { double(id: 1) }
+    let(:page) { double(objects: [note], number: 1) }
+
+    it 'fetches data' do
+      expect(client)
+        .to receive(:each_page)
+        .exactly(:once) # ensure to be cached on the second call
+        .with(:issue_comments, 'github/repo', issue.iid, page: 1)
+        .and_yield(page)
+
+      expect { |b| subject.each_object_to_import(&b) }.to yield_with_args(note)
+
+      subject.each_object_to_import {}
+
+      expect(
+        Gitlab::Cache::Import::Caching.set_includes?(
+          "github-importer/issue/notes/already-imported/#{project.id}",
+          issue.iid
+        )
+      ).to eq(true)
+    end
+
+    it 'skips cached pages' do
+      Gitlab::GithubImport::PageCounter
+        .new(project, "issue/#{issue.id}/issue_comments")
+        .set(2)
+
+      expect(client)
+        .to receive(:each_page)
+        .exactly(:once) # ensure to be cached on the second call
+        .with(:issue_comments, 'github/repo', issue.iid, page: 2)
+
+      subject.each_object_to_import {}
+    end
+
+    it 'skips cached merge requests' do
+      Gitlab::Cache::Import::Caching.set_add(
+        "github-importer/issue/notes/already-imported/#{project.id}",
+        issue.iid
+      )
+
+      expect(client).not_to receive(:each_page)
+
+      subject.each_object_to_import {}
+    end
+  end
+end

spec/lib/gitlab/github_import/importer/single_endpoint_merge_request_notes_importer_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::GithubImport::Importer::SingleEndpointMergeRequestNotesImporter do
+  let(:client) { double }
+  let(:project) { create(:project, import_source: 'github/repo') }
+
+  subject { described_class.new(project, client) }
+
+  it { is_expected.to include_module(Gitlab::GithubImport::ParallelScheduling) }
+  it { is_expected.to include_module(Gitlab::GithubImport::SingleEndpointNotesImporting) }
+  it { expect(subject.representation_class).to eq(Gitlab::GithubImport::Representation::Note) }
+  it { expect(subject.importer_class).to eq(Gitlab::GithubImport::Importer::NoteImporter) }
+  it { expect(subject.collection_method).to eq(:issue_comments) }
+  it { expect(subject.object_type).to eq(:note) }
+  it { expect(subject.id_for_already_imported_cache(double(id: 1))).to eq(1) }
+
+  describe '#each_object_to_import', :clean_gitlab_redis_cache do
+    let(:merge_request) do
+      create(
+        :merge_request,
+        iid: 999,
+        source_project: project,
+        target_project: project
+      )
+    end
+
+    let(:note) { double(id: 1) }
+    let(:page) { double(objects: [note], number: 1) }
+
+    it 'fetches data' do
+      expect(client)
+        .to receive(:each_page)
+        .exactly(:once) # ensure to be cached on the second call
+        .with(:issue_comments, 'github/repo', merge_request.iid, page: 1)
+        .and_yield(page)
+
+      expect { |b| subject.each_object_to_import(&b) }.to yield_with_args(note)
+
+      subject.each_object_to_import {}
+
+      expect(
+        Gitlab::Cache::Import::Caching.set_includes?(
+          "github-importer/merge_request/notes/already-imported/#{project.id}",
+          merge_request.iid
+        )
+      ).to eq(true)
+    end
+
+    it 'skips cached pages' do
+      Gitlab::GithubImport::PageCounter
+        .new(project, "merge_request/#{merge_request.id}/issue_comments")
+        .set(2)
+
+      expect(client)
+        .to receive(:each_page)
+        .exactly(:once) # ensure to be cached on the second call
+        .with(:issue_comments, 'github/repo', merge_request.iid, page: 2)
+
+      subject.each_object_to_import {}
+    end
+
+    it 'skips cached merge requests' do
+      Gitlab::Cache::Import::Caching.set_add(
+        "github-importer/merge_request/notes/already-imported/#{project.id}",
+        merge_request.iid
+      )
+
+      expect(client).not_to receive(:each_page)
+
+      subject.each_object_to_import {}
+    end
+  end
+end

spec/lib/gitlab/github_import/issuable_finder_spec.rb

@@ -3,7 +3,7 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::GithubImport::IssuableFinder, :clean_gitlab_redis_cache do
-  let(:project) { double(:project, id: 4) }
+  let(:project) { double(:project, id: 4, group: nil) }
   let(:issue) do
     double(:issue, issuable_type: MergeRequest, iid: 1)
   end
@@ -26,15 +26,77 @@ RSpec.describe Gitlab::GithubImport::IssuableFinder, :clean_gitlab_redis_cache d
 
       expect { finder.database_id }.to raise_error(TypeError)
     end
+
+    context 'when group is present' do
+      context 'when github_importer_single_endpoint_notes_import feature flag is enabled' do
+        it 'reads cache value with longer timeout' do
+          project = create(:project, import_url: 'http://t0ken@github.com/user/repo.git')
+          group = create(:group, projects: [project])
+
+          stub_feature_flags(github_importer_single_endpoint_notes_import: group)
+
+          expect(Gitlab::Cache::Import::Caching)
+            .to receive(:read)
+            .with(anything, timeout: Gitlab::Cache::Import::Caching::LONGER_TIMEOUT)
+
+          described_class.new(project, issue).database_id
+        end
+      end
+
+      context 'when github_importer_single_endpoint_notes_import feature flag is disabled' do
+        it 'reads cache value with default timeout' do
+          project = double(:project, id: 4, group: create(:group))
+
+          stub_feature_flags(github_importer_single_endpoint_notes_import: false)
+
+          expect(Gitlab::Cache::Import::Caching)
+            .to receive(:read)
+            .with(anything, timeout: Gitlab::Cache::Import::Caching::TIMEOUT)
+
+          described_class.new(project, issue).database_id
+        end
+      end
+    end
   end
 
   describe '#cache_database_id' do
     it 'caches the ID of a database row' do
       expect(Gitlab::Cache::Import::Caching)
         .to receive(:write)
-        .with('github-import/issuable-finder/4/MergeRequest/1', 10)
+        .with('github-import/issuable-finder/4/MergeRequest/1', 10, timeout: 86400)
 
       finder.cache_database_id(10)
     end
+
+    context 'when group is present' do
+      context 'when github_importer_single_endpoint_notes_import feature flag is enabled' do
+        it 'caches value with longer timeout' do
+          project = create(:project, import_url: 'http://t0ken@github.com/user/repo.git')
+          group = create(:group, projects: [project])
+
+          stub_feature_flags(github_importer_single_endpoint_notes_import: group)
+
+          expect(Gitlab::Cache::Import::Caching)
+            .to receive(:write)
+            .with(anything, anything, timeout: Gitlab::Cache::Import::Caching::LONGER_TIMEOUT)
+
+          described_class.new(project, issue).cache_database_id(10)
+        end
+      end
+
+      context 'when github_importer_single_endpoint_notes_import feature flag is disabled' do
+        it 'caches value with default timeout' do
+          project = double(:project, id: 4, group: create(:group))
+
+          stub_feature_flags(github_importer_single_endpoint_notes_import: false)
+
+          expect(Gitlab::Cache::Import::Caching)
+            .to receive(:write)
+            .with(anything, anything, timeout: Gitlab::Cache::Import::Caching::TIMEOUT)
+
+          described_class.new(project, issue).cache_database_id(10)
+        end
+      end
+    end
   end
 end

spec/lib/gitlab/github_import/sequential_importer_spec.rb

@@ -6,7 +6,7 @@ RSpec.describe Gitlab::GithubImport::SequentialImporter do
   describe '#execute' do
     it 'imports a project in sequence' do
       repository = double(:repository)
-      project = double(:project, id: 1, repository: repository, import_url: 'http://t0ken@github.another-domain.com/repo-org/repo.git')
+      project = double(:project, id: 1, repository: repository, import_url: 'http://t0ken@github.another-domain.com/repo-org/repo.git', group: nil)
       importer = described_class.new(project, token: 'foo')
 
       expect_next_instance_of(Gitlab::GithubImport::Importer::RepositoryImporter) do |instance|

spec/lib/gitlab/github_import_spec.rb

@@ -3,13 +3,17 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::GithubImport do
+  before do
+    stub_feature_flags(github_importer_lower_per_page_limit: false)
+  end
+
   context 'github.com' do
-    let(:project) { double(:project, import_url: 'http://t0ken@github.com/user/repo.git', id: 1) }
+    let(:project) { double(:project, import_url: 'http://t0ken@github.com/user/repo.git', id: 1, group: nil) }
 
     it 'returns a new Client with a custom token' do
       expect(described_class::Client)
         .to receive(:new)
-        .with('123', host: nil, parallel: true)
+        .with('123', host: nil, parallel: true, per_page: 100)
 
       described_class.new_client_for(project, token: '123')
     end
@@ -23,7 +27,7 @@ RSpec.describe Gitlab::GithubImport do
 
       expect(described_class::Client)
         .to receive(:new)
-        .with('123', host: nil, parallel: true)
+        .with('123', host: nil, parallel: true, per_page: 100)
 
       described_class.new_client_for(project)
     end
@@ -45,12 +49,12 @@ RSpec.describe Gitlab::GithubImport do
   end
 
   context 'GitHub Enterprise' do
-    let(:project) { double(:project, import_url: 'http://t0ken@github.another-domain.com/repo-org/repo.git') }
+    let(:project) { double(:project, import_url: 'http://t0ken@github.another-domain.com/repo-org/repo.git', group: nil) }
 
     it 'returns a new Client with a custom token' do
       expect(described_class::Client)
         .to receive(:new)
-        .with('123', host: 'http://github.another-domain.com/api/v3', parallel: true)
+        .with('123', host: 'http://github.another-domain.com/api/v3', parallel: true, per_page: 100)
 
       described_class.new_client_for(project, token: '123')
     end
@@ -64,7 +68,7 @@ RSpec.describe Gitlab::GithubImport do
 
       expect(described_class::Client)
         .to receive(:new)
-        .with('123', host: 'http://github.another-domain.com/api/v3', parallel: true)
+        .with('123', host: 'http://github.another-domain.com/api/v3', parallel: true, per_page: 100)
 
       described_class.new_client_for(project)
     end
@@ -88,4 +92,37 @@ RSpec.describe Gitlab::GithubImport do
       expect(described_class.formatted_import_url(project)).to eq('http://github.another-domain.com/api/v3')
     end
   end
+
+  describe '.per_page' do
+    context 'when project group is present' do
+      context 'when github_importer_lower_per_page_limit is enabled' do
+        it 'returns lower per page value' do
+          project = create(:project, import_url: 'http://t0ken@github.com/user/repo.git')
+          group = create(:group, projects: [project])
+
+          stub_feature_flags(github_importer_lower_per_page_limit: group)
+
+          expect(described_class.per_page(project)).to eq(Gitlab::GithubImport::Client::LOWER_PER_PAGE)
+        end
+      end
+
+      context 'when github_importer_lower_per_page_limit is disabled' do
+        it 'returns default per page value' do
+          project = double(:project, import_url: 'http://t0ken@github.com/user/repo.git', id: 1, group: create(:group))
+
+          stub_feature_flags(github_importer_lower_per_page_limit: false)
+
+          expect(described_class.per_page(project)).to eq(Gitlab::GithubImport::Client::DEFAULT_PER_PAGE)
+        end
+      end
+    end
+
+    context 'when project group is missing' do
+      it 'returns default per page value' do
+        project = double(:project, import_url: 'http://t0ken@github.com/user/repo.git', id: 1, group: nil)
+
+        expect(described_class.per_page(project)).to eq(Gitlab::GithubImport::Client::DEFAULT_PER_PAGE)
+      end
+    end
+  end
 end

spec/workers/gitlab/github_import/stage/import_issues_and_diff_notes_worker_spec.rb

@@ -10,7 +10,7 @@ RSpec.describe Gitlab::GithubImport::Stage::ImportIssuesAndDiffNotesWorker do
     it 'imports the issues and diff notes' do
       client = double(:client)
 
-      described_class::IMPORTERS.each do |klass|
+      worker.importers(project).each do |klass|
         importer = double(:importer)
         waiter = Gitlab::JobWaiter.new(2, '123')
 
@@ -31,4 +31,45 @@ RSpec.describe Gitlab::GithubImport::Stage::ImportIssuesAndDiffNotesWorker do
       worker.import(client, project)
     end
   end
+
+  describe '#importers' do
+    context 'when project group is present' do
+      let_it_be(:project) { create(:project) }
+      let_it_be(:group) { create(:group, projects: [project]) }
+
+      context 'when feature flag github_importer_single_endpoint_notes_import is enabled' do
+        it 'includes single endpoint diff notes importer' do
+          project = create(:project)
+          group = create(:group, projects: [project])
+
+          stub_feature_flags(github_importer_single_endpoint_notes_import: group)
+
+          expect(worker.importers(project)).to contain_exactly(
+            Gitlab::GithubImport::Importer::IssuesImporter,
+            Gitlab::GithubImport::Importer::SingleEndpointDiffNotesImporter
+          )
+        end
+      end
+
+      context 'when feature flag github_importer_single_endpoint_notes_import is disabled' do
+        it 'includes default diff notes importer' do
+          stub_feature_flags(github_importer_single_endpoint_notes_import: false)
+
+          expect(worker.importers(project)).to contain_exactly(
+            Gitlab::GithubImport::Importer::IssuesImporter,
+            Gitlab::GithubImport::Importer::DiffNotesImporter
+          )
+        end
+      end
+    end
+
+    context 'when project group is missing' do
+      it 'includes default diff notes importer' do
+        expect(worker.importers(project)).to contain_exactly(
+          Gitlab::GithubImport::Importer::IssuesImporter,
+          Gitlab::GithubImport::Importer::DiffNotesImporter
+        )
+      end
+    end
+  end
 end

spec/workers/gitlab/github_import/stage/import_notes_worker_spec.rb

@@ -8,18 +8,21 @@ RSpec.describe Gitlab::GithubImport::Stage::ImportNotesWorker do
 
   describe '#import' do
     it 'imports all the notes' do
-      importer = double(:importer)
       client = double(:client)
-      waiter = Gitlab::JobWaiter.new(2, '123')
 
-      expect(Gitlab::GithubImport::Importer::NotesImporter)
-        .to receive(:new)
-        .with(project, client)
-        .and_return(importer)
+      worker.importers(project).each do |klass|
+        importer = double(:importer)
+        waiter = Gitlab::JobWaiter.new(2, '123')
 
-      expect(importer)
-        .to receive(:execute)
-        .and_return(waiter)
+        expect(klass)
+          .to receive(:new)
+          .with(project, client)
+          .and_return(importer)
+
+        expect(importer)
+          .to receive(:execute)
+          .and_return(waiter)
+      end
 
       expect(Gitlab::GithubImport::AdvanceStageWorker)
         .to receive(:perform_async)
@@ -28,4 +31,43 @@ RSpec.describe Gitlab::GithubImport::Stage::ImportNotesWorker do
       worker.import(client, project)
     end
   end
+
+  describe '#importers' do
+    context 'when project group is present' do
+      let_it_be(:project) { create(:project) }
+      let_it_be(:group) { create(:group, projects: [project]) }
+
+      context 'when feature flag github_importer_single_endpoint_notes_import is enabled' do
+        it 'includes single endpoint mr and issue notes importers' do
+          project = create(:project)
+          group = create(:group, projects: [project])
+
+          stub_feature_flags(github_importer_single_endpoint_notes_import: group)
+
+          expect(worker.importers(project)).to contain_exactly(
+            Gitlab::GithubImport::Importer::SingleEndpointMergeRequestNotesImporter,
+            Gitlab::GithubImport::Importer::SingleEndpointIssueNotesImporter
+          )
+        end
+      end
+
+      context 'when feature flag github_importer_single_endpoint_notes_import is disabled' do
+        it 'includes default notes importer' do
+          stub_feature_flags(github_importer_single_endpoint_notes_import: false)
+
+          expect(worker.importers(project)).to contain_exactly(
+            Gitlab::GithubImport::Importer::NotesImporter
+          )
+        end
+      end
+    end
+
+    context 'when project group is missing' do
+      it 'includes default diff notes importer' do
+        expect(worker.importers(project)).to contain_exactly(
+          Gitlab::GithubImport::Importer::NotesImporter
+        )
+      end
+    end
+  end
 end