feat: support using BIGQUERY_EMULATOR_HOST environment variable

google/cloud/bigquery/_helpers.py

@@ -19,6 +19,7 @@
 import decimal
 import math
 import re
+import os
 from typing import Optional, Union
 
 from dateutil import relativedelta
@@ -28,8 +29,8 @@
 from google.cloud._helpers import _RFC3339_MICROS
 from google.cloud._helpers import _RFC3339_NO_FRACTION
 from google.cloud._helpers import _to_bytes
-import packaging.version
 
+import packaging.version
 
 _RFC3339_MICROS_NO_ZULU = "%Y-%m-%dT%H:%M:%S.%f"
 _TIMEONLY_WO_MICROS = "%H:%M:%S"
@@ -51,6 +52,16 @@
 
 _BQ_STORAGE_OPTIONAL_READ_SESSION_VERSION = packaging.version.Version("2.6.0")
 
+BIGQUERY_EMULATOR_HOST = "BIGQUERY_EMULATOR_HOST"
+"""Environment variable defining host for emulator."""
+
+_DEFAULT_HOST = "https://bigquery.googleapis.com"
+"""Default host for JSON API."""
+
+
+def _get_bigquery_host():
+ return os.environ.get(BIGQUERY_EMULATOR_HOST, _DEFAULT_HOST)
+
 
 class BQStorageVersions:
  """Version comparisons for google-cloud-bigqueyr-storage package."""

google/cloud/bigquery/client.py

@@ -56,7 +56,6 @@
 import google.cloud._helpers # type: ignore
 from google.cloud import exceptions # pytype: disable=import-error
 from google.cloud.client import ClientWithProject # type: ignore # pytype: disable=import-error
-
 from google.cloud.bigquery_storage_v1.services.big_query_read.client import (
  DEFAULT_CLIENT_INFO as DEFAULT_BQSTORAGE_CLIENT_INFO,
 )
@@ -67,6 +66,8 @@
 from google.cloud.bigquery._helpers import _record_field_to_json
 from google.cloud.bigquery._helpers import _str_or_none
 from google.cloud.bigquery._helpers import _verify_job_config_type
+from google.cloud.bigquery._helpers import _get_bigquery_host
+from google.cloud.bigquery._helpers import _DEFAULT_HOST
 from google.cloud.bigquery._http import Connection
 from google.cloud.bigquery import _pandas_helpers
 from google.cloud.bigquery.dataset import Dataset
@@ -230,6 +231,8 @@ def __init__(
  )
 
  kw_args = {"client_info": client_info}
+ bq_host = _get_bigquery_host()
+ kw_args["api_endpoint"] = bq_host if bq_host != _DEFAULT_HOST else None
  if client_options:
  if type(client_options) == dict:
  client_options = google.api_core.client_options.from_dict(

tests/unit/test__helpers.py

@@ -1288,3 +1288,29 @@ def test_decimal_as_float_api_repr():
  "parameterValue": {"value": 42.0},
  "name": "x",
  }
+
+
+class Test__get_bigquery_host(unittest.TestCase):
+ @staticmethod
+ def _call_fut():
+ from google.cloud.bigquery._helpers import _get_bigquery_host
+
+ return _get_bigquery_host()
+
+ def test_wo_env_var(self):
+ from google.cloud.bigquery._helpers import _DEFAULT_HOST
+
+ with mock.patch("os.environ", {}):
+ host = self._call_fut()
+
+ self.assertEqual(host, _DEFAULT_HOST)
+
+ def test_w_env_var(self):
+ from google.cloud.bigquery._helpers import BIGQUERY_EMULATOR_HOST
+
+ HOST = "https://api.example.com"
+
+ with mock.patch("os.environ", {BIGQUERY_EMULATOR_HOST: HOST}):
+ host = self._call_fut()
+
+ self.assertEqual(host, HOST)