Copy LFS objects when a repository is pull mirrored

What does this MR do?

Copies LFS objects into the repository when it is pull mirrored.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/10871

app/services/projects/lfs_pointers/lfs_import_service.rb

 # frozen_string_literal: true
 
-# This service manages the whole worflow of discovering the Lfs files in a
-# repository, linking them to the project and downloading (and linking) the non
-# existent ones.
+# This service is responbible of managing the retrieval of the lfs objects
+# to download and perform the download.
 module Projects
   module LfsPointers
     class LfsImportService < BaseService
-      include Gitlab::Utils::StrongMemoize
-
-      HEAD_REV = 'HEAD'.freeze
-      LFS_ENDPOINT_PATTERN = /^\t?url\s*=\s*(.+)$/.freeze
-      LFS_BATCH_API_ENDPOINT = '/info/lfs/objects/batch'.freeze
-
-      LfsImportError = Class.new(StandardError)
-
       def execute
-        return {} unless project&.lfs_enabled?
+        return success unless project&.lfs_enabled?
 
-        if external_lfs_endpoint?
-          # If the endpoint host is different from the import_url it means
-          # that the repo is using a third party service for storing the LFS files.
-          # In this case, we have to disable lfs in the project
-          disable_lfs!
+        lfs_objects_to_download = LfsObjectDownloadListService.new(project).execute
 
-          return {}
+        lfs_objects_to_download.each do |lfs_download_object|
+          LfsDownloadService.new(project, lfs_download_object).execute
         end
 
-        get_download_links
-      rescue LfsDownloadLinkListService::DownloadLinksError => e
-        raise LfsImportError, "The LFS objects download list couldn't be imported. Error: #{e.message}"
-      end
-
-      private
-
-      def external_lfs_endpoint?
-        lfsconfig_endpoint_uri && lfsconfig_endpoint_uri.host != import_uri.host
-      end
-
-      def disable_lfs!
-        project.update(lfs_enabled: false)
-      end
-
-      # rubocop: disable CodeReuse/ActiveRecord
-      def get_download_links
-        existent_lfs = LfsListService.new(project).execute
-        linked_oids = LfsLinkService.new(project).execute(existent_lfs.keys)
-
-        # Retrieving those oids not linked and which we need to download
-        not_linked_lfs = existent_lfs.except(*linked_oids)
-
-        LfsDownloadLinkListService.new(project, remote_uri: current_endpoint_uri).execute(not_linked_lfs)
-      end
-      # rubocop: enable CodeReuse/ActiveRecord
-
-      def lfsconfig_endpoint_uri
-        strong_memoize(:lfsconfig_endpoint_uri) do
-          # Retrieveing the blob data from the .lfsconfig file
-          data = project.repository.lfsconfig_for(HEAD_REV)
-          # Parsing the data to retrieve the url
-          parsed_data = data&.match(LFS_ENDPOINT_PATTERN)
-
-          if parsed_data
-            URI.parse(parsed_data[1]).tap do |endpoint|
-              endpoint.user ||= import_uri.user
-              endpoint.password ||= import_uri.password
-            end
-          end
-        end
-      rescue URI::InvalidURIError
-        raise LfsImportError, 'Invalid URL in .lfsconfig file'
-      end
-
-      def import_uri
-        @import_uri ||= URI.parse(project.import_url)
-      rescue URI::InvalidURIError
-        raise LfsImportError, 'Invalid project import URL'
-      end
-
-      def current_endpoint_uri
-        (lfsconfig_endpoint_uri || default_endpoint_uri)
-      end
-
-      # The import url must end with '.git' here we ensure it is
-      def default_endpoint_uri
-        @default_endpoint_uri ||= begin
-          import_uri.dup.tap do |uri|
-            path = uri.path.gsub(%r(/$), '')
-            path += '.git' unless path.ends_with?('.git')
-            uri.path = path + LFS_BATCH_API_ENDPOINT
-          end
-        end
+        success
+      rescue => e
+        error(e.message)
       end
     end
   end