BigQuery: Include SQL query and job ID in job errors

bigquery/google/cloud/bigquery/job.py

@@ -2846,6 +2846,36 @@ def _blocking_poll(self, timeout=None):
         self._done_timeout = timeout
         super(QueryJob, self)._blocking_poll(timeout=timeout)
 
+    @staticmethod
+    def _format_for_exception(query, job_id):
+        """Format a query for the output in exception message.
+
+        Args:
+            query (str): The SQL query to format.
+            job_id (str): The ID of the job that ran the query.
+
+        Returns: (str)
+            A formatted query text.
+        """
+        template = "\n\n(job ID: {job_id})\n\n{header}\n\n{ruler}\n{body}\n{ruler}"
+
+        lines = query.splitlines()
+        max_line_len = max(len(l) for l in lines)
+
+        header = "-----Query Job SQL Follows-----"
+        header = "{:^{total_width}}".format(header, total_width=max_line_len + 5)
+
+        # Print out a "ruler" above and below the SQL so we can judge columns.
+        # Left pad for the line numbers (4 digits plus ":").
+        ruler = "    |" + "    .    |" * (max_line_len // 10)
+
+        # Put line numbers next to the SQL.
+        body = "\n".join(
+            "{:4}:{}".format(n, line) for n, line in enumerate(lines, start=1)
+        )
+
+        return template.format(job_id=job_id, header=header, ruler=ruler, body=body)
+
     def result(self, timeout=None, page_size=None, retry=DEFAULT_RETRY):
         """Start the job and wait for it to complete and get the result.
 
@@ -2874,12 +2904,17 @@ def result(self, timeout=None, page_size=None, retry=DEFAULT_RETRY):
             concurrent.futures.TimeoutError:
                 If the job did not complete in the given timeout.
         """
-        super(QueryJob, self).result(timeout=timeout)
-        # Return an iterator instead of returning the job.
-        if not self._query_results:
-            self._query_results = self._client._get_query_results(
-                self.job_id, retry, project=self.project, location=self.location
-            )
+        try:
+            super(QueryJob, self).result(timeout=timeout)
+
+            # Return an iterator instead of returning the job.
+            if not self._query_results:
+                self._query_results = self._client._get_query_results(
+                    self.job_id, retry, project=self.project, location=self.location
+                )
+        except exceptions.GoogleCloudError as exc:
+            exc.message += self._format_for_exception(self.query, self.job_id)
+            raise
 
         # If the query job is complete but there are no query results, this was
         # special job, such as a DDL query. Return an empty result set to

bigquery/tests/unit/test_job.py

@@ -14,6 +14,7 @@
 
 import copy
 import json
+import textwrap
 import unittest
 
 import mock
@@ -4256,8 +4257,15 @@ def test_result_w_page_size(self):
     def test_result_error(self):
         from google.cloud import exceptions
 
+        query = textwrap.dedent(
+            """
+            SELECT foo, bar
+            FROM table_baz
+            WHERE foo == bar"""
+        )
+
         client = _make_client(project=self.PROJECT)
-        job = self._make_one(self.JOB_ID, self.QUERY, client)
+        job = self._make_one(self.JOB_ID, query, client)
         error_result = {
             "debugInfo": "DEBUG",
             "location": "LOCATION",
@@ -4277,6 +4285,15 @@ def test_result_error(self):
         self.assertIsInstance(exc_info.exception, exceptions.GoogleCloudError)
         self.assertEqual(exc_info.exception.code, http_client.BAD_REQUEST)
 
+        full_text = str(exc_info.exception)
+
+        assert job.job_id in full_text
+        assert "Query Job SQL Follows" in full_text
+
+        for i, line in enumerate(query.splitlines(), start=1):
+            expected_line = "{}:{}".format(i, line)
+            assert expected_line in full_text
+
     def test_begin_w_bound_client(self):
         from google.cloud.bigquery.dataset import DatasetReference
         from google.cloud.bigquery.job import QueryJobConfig