Backup task should continue on corrupt repositories

Problem

Currently the GitLab backup rake task will abort the backup in the following situations:

• Corrupt repository
  • We fail to call empty_repo? on the project as it is corrupt Rugged::OdbError https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/backup/repository.rb#L17 - requires rescue
  • Executing git bundle fails - we call abort
    • https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/backup/repository.rb#L33
• Tar'ing the directory fails (unlikely) - https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/backup/repository.rb#L22

Solution

Make the backup task more flexible. In the situations above we should simply mark the backup for that repostiory as "failed" and continue. Administrators would rather have 99 out of 100 repositories backed up if one fails, instead of none.

• https://gitlab.zendesk.com/agent/tickets/75044