(PXP-8853): Explain why MDS 404 might be ok in logs

[johnfrancismccann]

Jira ticket

The indexs3client job was previously modified to support populating Metadata Service objects after running gen3-client upload ... with the --metadata option supplied. Because the job has no way of knowing whether or not --metadata was supplied, it always attempts to update an MDS object corresponding to the GUID parsed out of the job's input (an S3 url).

This means that after a user uploads a file without --metadata, MDS will return a 404 to the job for the attempted object update. The job doesn't fail because --metadata might not have been supplied, but it does log the 404, which has been a source of confusion (see ticket) for engineers.

This ticket aims to add information to the log message explaining why a 404 from MDS isn't necessarily a problem.

Improvements

• Explain in logs why a 404 from MDS isn't necessarily a problem.