1 files changed, 83 insertions, 0 deletions
diff --git a/lib/gitlab/github_import/importer/pull_requests_importer.rb b/lib/gitlab/github_import/importer/pull_requests_importer.rb
new file mode 100644
index 00000000000..5437e32e9f1
--- /dev/null
+++ b/lib/gitlab/github_import/importer/pull_requests_importer.rb
@@ -0,0 +1,83 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module GithubImport
+    module Importer
+      class PullRequestsImporter
+        include ParallelScheduling
+
+        def importer_class
+          PullRequestImporter
+        end
+
+        def representation_class
+          Representation::PullRequest
+        end
+
+        def sidekiq_worker_class
+          ImportPullRequestWorker
+        end
+
+        def id_for_already_imported_cache(pr)
+          pr.number
+        end
+
+        def each_object_to_import
+          super do |pr|
+            update_repository if update_repository?(pr)
+            yield pr
+          end
+        end
+
+        def update_repository
+          # We set this column _before_ fetching the repository, and this is
+          # deliberate. If we were to update this column after the fetch we may
+          # miss out on changes pushed during the fetch or between the fetch and
+          # updating the timestamp.
+          project.update_column(:last_repository_updated_at, Time.zone.now)
+
+          project.repository.fetch_remote('github', forced: false)
+
+          pname = project.path_with_namespace
+
+          Rails.logger
+            .info("GitHub importer finished updating repository for #{pname}")
+
+          repository_updates_counter.increment(project: pname)
+        end
+
+        def update_repository?(pr)
+          last_update = project.last_repository_updated_at || project.created_at
+
+          return false if pr.updated_at < last_update
+
+          # PRs may be updated without there actually being new commits, thus we
+          # check to make sure we only re-fetch if truly necessary.
+          !(commit_exists?(pr.head.sha) && commit_exists?(pr.base.sha))
+        end
+
+        def commit_exists?(sha)
+          project.repository.lookup(sha)
+          true
+        rescue Rugged::Error
+          false
+        end
+
+        def collection_method
+          :pull_requests
+        end
+
+        def collection_options
+          { state: 'all', sort: 'created', direction: 'asc' }
+        end
+
+        def repository_updates_counter
+          @repository_updates_counter ||= Gitlab::Metrics.counter(
+            :github_importer_repository_updates,
+            'The number of times repositories have to be updated again'
+          )
+        end
+      end
+    end
+  end
+end