fix(handlers): add debug messages for repository blob link checking
Related to: Corrective Action: Improve debug logging around... (#1015 - closed)
This MR adds more debug log messages for repository blob link checking. During gitlab-com/gl-infra/production#14260 (closed)+ it was difficult to determine why we were failing to find layer blobs as three distinct scenarios produce the same error message. Namely:
- the repository isn't in the database
- the blob link isn't in the database
- the blob link isn't found when the blob is served
Along with Enable Debug Logging for Registry in Pre and St... (#1018 - closed) this will ensure that we can tell these three scenarios apart on our non-production environments.
Edited by Hayley Swimelar