When an error occurs in the Kafka driver, the error object always comes up as empty (error={}). Example log entry:
[2016-10-21T04:12:36.421Z] ERROR: changeprop/6416 on scb1002: Commit failed (offset=56918686, error={}, levelPath=error/commit/ores_cache) event: {"comment": "Grammar updates", "database": "enwiki", "meta": {"domain": "en.wikipedia.org", "dt": "2016-10-21T04:12:34+00:00", "id": "97dcb5f7-9744-11e6-97ea-b083fecf0ff5", "request_id": "024177e0-436b-4edc-85fb-a1da35c884d5", "schema_uri": "mediawiki/revision/create/1", "topic": "mediawiki.revision-create", "uri": "https://en.wikipedia.org/wiki/Resident_Evil_4"}, "page_id": 1310512, "page_is_redirect": false, "page_namespace": 0, "page_title": "Resident_Evil_4", "performer": {"user_groups": ["*"], "user_is_bot": false, "user_text": "74.69.227.55"}, "rev_content_format": "wikitext", "rev_content_model": "wikitext", "rev_id": 745439400, "rev_len": 90271, "rev_minor_edit": false, "rev_parent_id": 743505744, "rev_sha1": "jj7h5576x9fxk8zjg6292jq9d1kucrd", "rev_timestamp": "2016-10-21T04:12:34Z"}