load_facet in browse lists should not proceed if the CSV file is empty

[sandbergja]

What maintenance needs to be done?

The load_facet method in the BrowseLists module should check to make sure that the CSV is a reasonable size before it does its work.

Level of urgency

• High
• Moderate
• Low

Why is this maintenance needed?

This way, if the previous task has failed and produces an empty CSV, we do not end up with a completely empty browse list.

Currently, we can experience the following situation:

• there is an error in, say, the browse:name_titles rake task
• the error causes the /tmp/alma_orangelight_name_titles.csv file to be totally empty
• load_facet doesn't check the file size, and happily TRUNCATEs the entire table
• Since the csv file is empty, load_facet cannot add any data back into the table
• The production database has an empty browse list :-(

Acceptance criteria

• load_facet does not TRUNCATE the current data if the relevant csv file is empty
• load_facet does not TRUNCATE the current data if the relevant csv file is much smaller than it should be