Add logs get ES response when in case of assert error.

Author: everaldorodrigo

biothings/web/query/formatter.py

@@ -87,13 +87,17 @@ def __init__(self, *args, **kwargs):
             # make sure the document is coming from
             # elasticsearch at initialization time
             if "hits" not in self.data:
+                logger.error("ES response missing 'hits' field. Response data: %s", self.data)
                 raise ValueError("Response missing 'hits' field")
             if "total" not in self.data["hits"]:
+                logger.error("ES response missing 'hits.total' field. Response data: %s", self.data)
                 raise ValueError("Response missing 'hits.total' field")
             if "hits" not in self.data["hits"]:
+                logger.error("ES response missing 'hits.hits' field. Response data: %s", self.data)
                 raise ValueError("Response missing 'hits.hits' field")
             for hit in self.data["hits"]["hits"]:
                 if "_source" not in hit:
+                    logger.error("ES hit missing '_source' field. Hit data: %s", hit)
                     raise ValueError("Hit missing '_source' field")
 
     class _Doc(Doc):