Adds Rollback functionality to HashedStorage migration

We are adding sidekiq workers and service classes to allow to rollback
a hashed storage migration. There are some refactoring involved as well
as part of the code can be reused by both the migration and the rollback
logic.

3 files changed, 142 insertions, 0 deletions

diff --git a/app/services/projects/hashed_storage/rollback_attachments_service.rb b/app/services/projects/hashed_storage/rollback_attachments_service.rb
new file mode 100644
index 00000000000..5183609ab85
--- /dev/null
+++ b/app/services/projects/hashed_storage/rollback_attachments_service.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+module Projects
+  module HashedStorage
+    AttachmentRollbackError = Class.new(StandardError)
+
+    class RollbackAttachmentsService < BaseService
+      attr_reader :logger, :old_disk_path
+
+      def initialize(project, logger: nil)
+        @project = project
+        @logger = logger || Rails.logger
+      end
+
+      def execute
+        origin = FileUploader.absolute_base_dir(project)
+        project.storage_version = ::Project::HASHED_STORAGE_FEATURES[:repository]
+        target = FileUploader.absolute_base_dir(project)
+
+        result = move_folder!(origin, target)
+        project.save!
+
+        if result && block_given?
+          yield
+        end
+
+        result
+      end
+
+      private
+
+      def move_folder!(old_path, new_path)
+        unless File.directory?(old_path)
+          logger.info("Skipped attachments rollback from '#{old_path}' to '#{new_path}', source path doesn't exist or is not a directory (PROJECT_ID=#{project.id})")
+          return true
+        end
+
+        if File.exist?(new_path)
+          logger.error("Cannot rollback attachments from '#{old_path}' to '#{new_path}', target path already exist (PROJECT_ID=#{project.id})")
+          raise AttachmentRollbackError, "Target path '#{new_path}' already exist"
+        end
+
+        # Create hashed storage base path folder
+        FileUtils.mkdir_p(File.dirname(new_path))
+
+        FileUtils.mv(old_path, new_path)
+        logger.info("Rolledback project attachments from '#{old_path}' to '#{new_path}' (PROJECT_ID=#{project.id})")
+
+        true
+      end
+    end
+  end
+end
diff --git a/app/services/projects/hashed_storage/rollback_repository_service.rb b/app/services/projects/hashed_storage/rollback_repository_service.rb
new file mode 100644
index 00000000000..b57d05c50ca
--- /dev/null
+++ b/app/services/projects/hashed_storage/rollback_repository_service.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+module Projects
+  module HashedStorage
+    class RollbackRepositoryService < BaseRepositoryService
+      def execute
+        try_to_set_repository_read_only!
+
+        @old_storage_version = project.storage_version
+        project.storage_version = nil
+        project.ensure_storage_path_exists
+
+        @new_disk_path = project.disk_path
+
+        result = move_repository(old_disk_path, new_disk_path)
+
+        if move_wiki
+          result &&= move_repository("#{old_wiki_disk_path}", "#{new_disk_path}.wiki")
+        end
+
+        if result
+          project.write_repository_config
+          project.track_project_repository
+        else
+          rollback_folder_move
+          project.storage_version = ::Project::HASHED_STORAGE_FEATURES[:repository]
+        end
+
+        project.repository_read_only = false
+        project.save!
+
+        if result && block_given?
+          yield
+        end
+
+        result
+      end
+
+      private
+
+      def try_to_set_repository_read_only!
+        # Mitigate any push operation to start during migration
+        unless project.set_repository_read_only!
+          migration_error = "Target repository '#{old_disk_path}' cannot be made read-only as there is a git transfer in progress"
+          logger.error migration_error
+
+          raise RepositoryRollbackError, migration_error
+        end
+      end
+    end
+  end
+end
diff --git a/app/services/projects/hashed_storage/rollback_service.rb b/app/services/projects/hashed_storage/rollback_service.rb
new file mode 100644
index 00000000000..25767f5de5e
--- /dev/null
+++ b/app/services/projects/hashed_storage/rollback_service.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module Projects
+  module HashedStorage
+    class RollbackService < BaseService
+      attr_reader :logger, :old_disk_path
+
+      def initialize(project, old_disk_path, logger: nil)
+        @project = project
+        @old_disk_path = old_disk_path
+        @logger = logger || Rails.logger
+      end
+
+      def execute
+        # Rollback attachments from Hashed Storage to Legacy
+        if project.hashed_storage?(:attachments)
+          return false unless rollback_attachments
+        end
+
+        # Rollback repository from Hashed Storage to Legacy
+        if project.hashed_storage?(:repository)
+          rollback_repository
+        end
+      end
+
+      private
+
+      def rollback_attachments
+        HashedStorage::RollbackAttachmentsService.new(project, logger: logger).execute
+      end
+
+      def rollback_repository
+        HashedStorage::RollbackRepositoryService.new(project, old_disk_path, logger: logger).execute
+      end
+    end
+  end
+end