Log error inside of rescue_from block of BatchItemProcessingJob

[afred]

Background: the method BatchItemProcessingJob#rescue_from will execute if there's an exception raised at some point during the deserialization process. Errors can occur for a variety of reasons, one of which is a faulty connection to the database.

In such case, the BatchItem will not be retrievable (and will end up being nil), which causes batch_item.update to raise a subsequent error, and we never get to see the message inside of exception.message.

Done when: we call Rails.logger.warn exception.message inside of BatchItemProcessingJob#rescue_from before the call to batch_item.update.

Or... we need to at least log exception.message in a place where we'll find it if we go looking. I would think the most obvious place would be the Rails log.. but open to suggestions.