Add client_info to BigQuery constructor for user-amenable user agent headers

This aligns BigQuery's behavior regarding the User-Agent and
X-Goog-Api-Client headers with that of the GAPIC-based clients.

Old:

    X-Goog-API-Client: gl-python/3.7.2 gccl/1.11.2
    User-Agent: gcloud-python/0.29.1

New:

    X-Goog-API-Client: optional-application-id/1.2.3 gl-python/3.7.2 grpc/1.20.0 gax/1.9.0 gapic/1.11.2 gccl/1.11.2
    User-Agent: optional-application-id/1.2.3 gl-python/3.7.2 grpc/1.20.0 gax/1.9.0 gapic/1.11.2 gccl/1.11.2

In order to set the `optional-application-id/1.2.3`, the latest version
of `api_core` is required, but since that's an uncommon usecase and it
doesn't break, just ignore the custom User-Agent if an older version is
used, I didn't update the minimum version `setup.py`.

Author: tswast

bigquery/google/cloud/bigquery/_http.py

@@ -14,21 +14,32 @@
 
 """Create / interact with Google BigQuery connections."""
 
+import google.api_core.gapic_v1.client_info
 from google.cloud import _http
 
 from google.cloud.bigquery import __version__
 
 
-_CLIENT_INFO = _http.CLIENT_INFO_TEMPLATE.format(__version__)
-
-
 class Connection(_http.JSONConnection):
     """A connection to Google BigQuery via the JSON REST API.
 
     :type client: :class:`~google.cloud.bigquery.client.Client`
     :param client: The client that owns the current connection.
     """
 
+    def __init__(self, client, client_info=None):
+        super(Connection, self).__init__(client)
+
+        if client_info is None:
+            client_info = google.api_core.gapic_v1.client_info.ClientInfo(
+                gapic_version=__version__, client_library_version=__version__
+            )
+        else:
+            client_info.gapic_version = __version__
+            client_info.client_library_version = __version__
+        self._client_info = client_info
+        self._extra_headers = {}
+
     API_BASE_URL = "https://www.googleapis.com"
     """The base of the API call URL."""
 
@@ -38,4 +49,19 @@ class Connection(_http.JSONConnection):
     API_URL_TEMPLATE = "{api_base_url}/bigquery/{api_version}{path}"
     """A template for the URL of a particular API call."""
 
-    _EXTRA_HEADERS = {_http.CLIENT_INFO_HEADER: _CLIENT_INFO}
+    @property
+    def USER_AGENT(self):
+        return self._client_info.to_user_agent()
+
+    @USER_AGENT.setter
+    def USER_AGENT(self, value):
+        self._client_info.user_agent = value
+
+    @property
+    def _EXTRA_HEADERS(self):
+        self._extra_headers[_http.CLIENT_INFO_HEADER] = self._client_info.to_user_agent()
+        return self._extra_headers
+
+    @_EXTRA_HEADERS.setter
+    def _EXTRA_HEADERS(self, value):
+        self._extra_headers = value

bigquery/google/cloud/bigquery/client.py

@@ -128,6 +128,11 @@ class Client(ClientWithProject):
         default_query_job_config (google.cloud.bigquery.job.QueryJobConfig):
             (Optional) Default ``QueryJobConfig``.
             Will be merged into job configs passed into the ``query`` method.
+        client_info (google.api_core.gapic_v1.client_info.ClientInfo):
+            The client info used to send a user-agent string along with API
+            requests. If ``None``, then default info will be used. Generally,
+            you only need to set this if you're developing your own library
+            or partner tool.
 
     Raises:
         google.auth.exceptions.DefaultCredentialsError:
@@ -148,11 +153,12 @@ def __init__(
         _http=None,
         location=None,
         default_query_job_config=None,
+        client_info=None,
     ):
         super(Client, self).__init__(
             project=project, credentials=credentials, _http=_http
         )
-        self._connection = Connection(self)
+        self._connection = Connection(self, client_info=client_info)
         self._location = location
         self._default_query_job_config = default_query_job_config
 

bigquery/tests/unit/test__http.py

@@ -45,9 +45,36 @@ def test_build_api_url_w_extra_query_params(self):
         parms = dict(parse_qsl(qs))
         self.assertEqual(parms["bar"], "baz")
 
+    def test_user_agent(self):
+        from google.cloud import _http as base_http
+
+        http = mock.create_autospec(requests.Session, instance=True)
+        response = requests.Response()
+        response.status_code = 200
+        data = b"brent-spiner"
+        response._content = data
+        http.request.return_value = response
+        client = mock.Mock(_http=http, spec=["_http"])
+
+        conn = self._make_one(client)
+        conn.USER_AGENT = "my-application/1.2.3"
+        req_data = "req-data-boring"
+        result = conn.api_request("GET", "/rainbow", data=req_data, expect_json=False)
+        self.assertEqual(result, data)
+
+        expected_headers = {
+            "Accept-Encoding": "gzip",
+            base_http.CLIENT_INFO_HEADER: conn.USER_AGENT,
+            "User-Agent": conn.USER_AGENT,
+        }
+        expected_uri = conn.build_api_url("/rainbow")
+        http.request.assert_called_once_with(
+            data=req_data, headers=expected_headers, method="GET", url=expected_uri
+        )
+        self.assertIn("my-application/1.2.3", conn.USER_AGENT)
+
     def test_extra_headers(self):
         from google.cloud import _http as base_http
-        from google.cloud.bigquery import _http as MUT
 
         http = mock.create_autospec(requests.Session, instance=True)
         response = requests.Response()
@@ -58,14 +85,44 @@ def test_extra_headers(self):
         client = mock.Mock(_http=http, spec=["_http"])
 
         conn = self._make_one(client)
+        conn._EXTRA_HEADERS["x-test-header"] = "a test value"
+        req_data = "req-data-boring"
+        result = conn.api_request("GET", "/rainbow", data=req_data, expect_json=False)
+        self.assertEqual(result, data)
+
+        expected_headers = {
+            "Accept-Encoding": "gzip",
+            base_http.CLIENT_INFO_HEADER: conn.USER_AGENT,
+            "User-Agent": conn.USER_AGENT,
+            "x-test-header": "a test value",
+        }
+        expected_uri = conn.build_api_url("/rainbow")
+        http.request.assert_called_once_with(
+            data=req_data, headers=expected_headers, method="GET", url=expected_uri
+        )
+
+    def test_extra_headers_replace(self):
+        from google.cloud import _http as base_http
+
+        http = mock.create_autospec(requests.Session, instance=True)
+        response = requests.Response()
+        response.status_code = 200
+        data = b"brent-spiner"
+        response._content = data
+        http.request.return_value = response
+        client = mock.Mock(_http=http, spec=["_http"])
+
+        conn = self._make_one(client)
+        conn._EXTRA_HEADERS = {"x-test-header": "a test value"}
         req_data = "req-data-boring"
         result = conn.api_request("GET", "/rainbow", data=req_data, expect_json=False)
         self.assertEqual(result, data)
 
         expected_headers = {
             "Accept-Encoding": "gzip",
-            base_http.CLIENT_INFO_HEADER: MUT._CLIENT_INFO,
+            base_http.CLIENT_INFO_HEADER: conn.USER_AGENT,
             "User-Agent": conn.USER_AGENT,
+            "x-test-header": "a test value",
         }
         expected_uri = conn.build_api_url("/rainbow")
         http.request.assert_called_once_with(

bigquery/tests/unit/test_client.py

@@ -22,6 +22,7 @@
 import unittest
 
 import mock
+import requests
 import six
 from six.moves import http_client
 import pytest
@@ -37,6 +38,7 @@
     pyarrow = None
 
 import google.api_core.exceptions
+from google.api_core.gapic_v1 import client_info
 import google.cloud._helpers
 from google.cloud.bigquery.dataset import DatasetReference
 
@@ -1320,6 +1322,38 @@ def test_get_table(self):
         conn.api_request.assert_called_once_with(method="GET", path="/%s" % path)
         self.assertEqual(table.table_id, self.TABLE_ID)
 
+    def test_get_table_sets_user_agent(self):
+        creds = _make_credentials()
+        http = mock.create_autospec(requests.Session)
+        mock_response = http.request(
+            url=mock.ANY, method=mock.ANY, headers=mock.ANY, data=mock.ANY
+        )
+        http.reset_mock()
+        mock_response.status_code = 200
+        mock_response.json.return_value = self._make_table_resource()
+        user_agent_override = client_info.ClientInfo(user_agent="my-application/1.2.3")
+        client = self._make_one(
+            project=self.PROJECT,
+            credentials=creds,
+            client_info=user_agent_override,
+            _http=http,
+        )
+
+        table = client.get_table(self.TABLE_REF)
+
+        expected_user_agent = user_agent_override.to_user_agent()
+        http.request.assert_called_once_with(
+            url=mock.ANY,
+            method="GET",
+            headers={
+                "X-Goog-API-Client": expected_user_agent,
+                "Accept-Encoding": "gzip",
+                "User-Agent": expected_user_agent,
+            },
+            data=mock.ANY,
+        )
+        self.assertIn("my-application/1.2.3", expected_user_agent)
+
     def test_update_dataset_w_invalid_field(self):
         from google.cloud.bigquery.dataset import Dataset