1 files changed, 64 insertions, 0 deletions
diff --git a/app/services/projects/container_repository/third_party/delete_tags_service.rb b/app/services/projects/container_repository/third_party/delete_tags_service.rb
new file mode 100644
index 00000000000..6504172109e
--- /dev/null
+++ b/app/services/projects/container_repository/third_party/delete_tags_service.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+module Projects
+  module ContainerRepository
+    module ThirdParty
+      class DeleteTagsService
+        include BaseServiceUtility
+
+        def initialize(container_repository, tag_names)
+          @container_repository = container_repository
+          @tag_names = tag_names
+        end
+
+        # Replace a tag on the registry with a dummy tag.
+        # This is a hack as the registry doesn't support deleting individual
+        # tags. This code effectively pushes a dummy image and assigns the tag to it.
+        # This way when the tag is deleted only the dummy image is affected.
+        # This is used to preverse compatibility with third-party registries that
+        # don't support fast delete.
+        # See https://gitlab.com/gitlab-org/gitlab/issues/15737 for a discussion
+        def execute
+          return success(deleted: []) if @tag_names.empty?
+
+          # generates the blobs for the dummy image
+          dummy_manifest = @container_repository.client.generate_empty_manifest(@container_repository.path)
+          return error('could not generate manifest') if dummy_manifest.nil?
+
+          deleted_tags = replace_tag_manifests(dummy_manifest)
+
+          # Deletes the dummy image
+          # All created tag digests are the same since they all have the same dummy image.
+          # a single delete is sufficient to remove all tags with it
+          if deleted_tags.any? && @container_repository.delete_tag_by_digest(deleted_tags.each_value.first)
+            success(deleted: deleted_tags.keys)
+          else
+            error('could not delete tags')
+          end
+        end
+
+        private
+
+        # update the manifests of the tags with the new dummy image
+        def replace_tag_manifests(dummy_manifest)
+          deleted_tags = {}
+
+          @tag_names.each do |name|
+            digest = @container_repository.client.put_tag(@container_repository.path, name, dummy_manifest)
+            next unless digest
+
+            deleted_tags[name] = digest
+          end
+
+          # make sure the digests are the same (it should always be)
+          digests = deleted_tags.values.uniq
+
+          # rubocop: disable CodeReuse/ActiveRecord
+          Gitlab::ErrorTracking.track_and_raise_for_dev_exception(ArgumentError.new('multiple tag digests')) if digests.many?
+
+          deleted_tags
+        end
+      end
+    end
+  end
+end