Feat: add support for using provided credentials in non-Vertex mode.

google/genai/_api_client.py

@@ -702,7 +702,21 @@ def __init__(
         )
       self._http_options.api_version = 'v1beta1'
     else:  # Implicit initialization or missing arguments.
-      if not self.api_key:
+      if env_api_key and api_key:
+        # Explicit api_key takes precedence over implicit api_key.
+        logger.info(
+            'The client initializer api_key argument takes '
+            'precedence over the API key from the environment variable.'
+        )
+      if credentials:
+        if env_api_key:
+          logger.info(
+              'The user `credentials` argument will take precedence over the'
+              ' api key from the environment variables.'
+          )
+          self.api_key = None
+
+      if not self.api_key and not credentials:
         raise ValueError(
             'No API key was provided. Please pass a valid API key. Learn how to'
             ' create an API key at'
@@ -1175,20 +1189,21 @@ def _request_once(
       stream: bool = False,
   ) -> HttpResponse:
     data: Optional[Union[str, bytes]] = None
-    # If using proj/location, fetch ADC
-    if self.vertexai and (self.project or self.location):
+
+    uses_vertex_creds = self.vertexai and (self.project or self.location)
+    uses_mldev_creds = not self.vertexai and self._credentials
+    if (uses_vertex_creds or uses_mldev_creds):
       http_request.headers['Authorization'] = f'Bearer {self._access_token()}'
       if self._credentials and self._credentials.quota_project_id:
         http_request.headers['x-goog-user-project'] = (
             self._credentials.quota_project_id
         )
-      data = json.dumps(http_request.data) if http_request.data else None
-    else:
-      if http_request.data:
-        if not isinstance(http_request.data, bytes):
-          data = json.dumps(http_request.data) if http_request.data else None
-        else:
-          data = http_request.data
+
+    if http_request.data:
+      if not isinstance(http_request.data, bytes):
+        data = json.dumps(http_request.data)
+      else:
+        data = http_request.data
 
     if stream:
       httpx_request = self._httpx_client.build_request(
@@ -1241,22 +1256,22 @@ async def _async_request_once(
   ) -> HttpResponse:
     data: Optional[Union[str, bytes]] = None
 
-    # If using proj/location, fetch ADC
-    if self.vertexai and (self.project or self.location):
+    uses_vertex_creds = self.vertexai and (self.project or self.location)
+    uses_mldev_creds = not self.vertexai and self._credentials
+    if (uses_vertex_creds or uses_mldev_creds):
       http_request.headers['Authorization'] = (
           f'Bearer {await self._async_access_token()}'
       )
       if self._credentials and self._credentials.quota_project_id:
         http_request.headers['x-goog-user-project'] = (
             self._credentials.quota_project_id
         )
-      data = json.dumps(http_request.data) if http_request.data else None
-    else:
-      if http_request.data:
-        if not isinstance(http_request.data, bytes):
-          data = json.dumps(http_request.data) if http_request.data else None
-        else:
-          data = http_request.data
+
+    if http_request.data:
+      if not isinstance(http_request.data, bytes):
+        data = json.dumps(http_request.data)
+      else:
+        data = http_request.data
 
     if stream:
       if self._use_aiohttp():

google/genai/tests/client/test_client_initialization.py

@@ -47,6 +47,28 @@
 )
 
 
+class FakeCredentials(credentials.Credentials):
+  def __init__(self, token="fake_token", expired=False, quota_project_id=None):
+    super().__init__()
+    self.token = token
+    self._expired = expired
+    self._quota_project_id = quota_project_id
+    self.refresh_count = 0
+
+  @property
+  def expired(self):
+    return self._expired
+
+  @property
+  def quota_project_id(self):
+    return self._quota_project_id
+
+  def refresh(self, request):
+    self.refresh_count += 1
+    self.token = "refreshed_token"
+    self._expired = False
+
+
 @pytest.fixture(autouse=True)
 def reset_has_aiohttp():
   yield
@@ -1721,3 +1743,142 @@ async def test_get_aiohttp_session():
   assert initial_session is not None
   session = await client._api_client._get_aiohttp_session()
   assert session is initial_session
+
+
+def test_missing_api_key_and_credentials(monkeypatch):
+  monkeypatch.setenv("GOOGLE_API_KEY", "")
+  with pytest.raises(ValueError, match="No API key was provided"):
+    Client()
+
+
+auth_precedence_test_cases = [
+    # client_args, env_vars, expected_headers
+    (
+        {"credentials": FakeCredentials()},
+        {"GOOGLE_API_KEY": "env_api_key"},
+        {"Authorization": "Bearer fake_token"}
+    ),
+    (
+        {"credentials": FakeCredentials(quota_project_id="quota-proj")},
+        {"GOOGLE_API_KEY": "env_api_key"},
+        {
+            "Authorization": "Bearer fake_token",
+            "x-goog-user-project": "quota-proj"
+        }
+    ),
+    (
+        {"api_key": "test_api_key"},
+        {"GOOGLE_API_KEY": "env_api_key"},
+        {"x-goog-api-key": "test_api_key"}
+    ),
+    (
+        {},
+        {"GOOGLE_API_KEY": "env_api_key"},
+        {"x-goog-api-key": "env_api_key"}
+    ),
+]
+
+
+@pytest.mark.parametrize(
+    ["client_kwargs", "env_vars", "expected_headers"],
+    auth_precedence_test_cases,
+)
+@mock.patch.object(httpx.Client, "send", autospec=True)
+def test_auth_precedence_mldev(mock_send, monkeypatch, client_kwargs, env_vars, expected_headers):
+  for key, value in env_vars.items():
+    monkeypatch.setenv(key, value)
+
+  client = Client(**client_kwargs)
+  mock_send.return_value = httpx.Response(
+      status_code=200,
+      json={"candidates": [{"content": {"parts": [{"text": "response"}]}}]}
+  )
+  client.models.generate_content(model="test", contents="hello?")
+  mock_send.assert_called_once()
+  request = mock_send.call_args[0][1]
+
+  for key, value in expected_headers.items():
+    assert key in request.headers
+    assert request.headers[key] == value
+
+  if "Authorization" in expected_headers:
+    assert "x-goog-api-key" not in request.headers
+  if "x-goog-api-key" in expected_headers:
+    assert "Authorization" not in request.headers
+  if "x-goog-user-project" not in expected_headers:
+    assert "x-goog-user-project" not in request.headers
+  assert request.content == b'{"contents": [{"parts": [{"text": "hello?"}], "role": "user"}]}'
+
+@pytest.mark.parametrize(
+    ["client_kwargs", "env_vars", "expected_headers"],
+    auth_precedence_test_cases,
+)
+@pytest.mark.asyncio
+@mock.patch.object(httpx.AsyncClient, "send", autospec=True)
+async def test_async_auth_precedence_mldev(mock_send, monkeypatch, client_kwargs, env_vars, expected_headers):
+  for key, value in env_vars.items():
+    monkeypatch.setenv(key, value)
+
+  client = Client(**client_kwargs)
+  mock_send.return_value = httpx.Response(
+      status_code=200,
+      json={"candidates": [{"content": {"parts": [{"text": "response"}]}}]}
+  )
+  await client.aio.models.generate_content(model="test", contents="hello?")
+  mock_send.assert_called_once()
+  request = mock_send.call_args[0][1]
+
+  for key, value in expected_headers.items():
+    assert key in request.headers
+    assert request.headers[key] == value
+
+  if "Authorization" in expected_headers:
+    assert "x-goog-api-key" not in request.headers
+  if "x-goog-api-key" in expected_headers:
+    assert "Authorization" not in request.headers
+  if "x-goog-user-project" not in expected_headers:
+    assert "x-goog-user-project" not in request.headers
+  assert request.content == b'{"contents": [{"parts": [{"text": "hello?"}], "role": "user"}]}'
+
+
+@pytest.mark.asyncio
+async def test_both_credentials_mldev():
+  with pytest.raises(ValueError, match="mutually exclusive"):
+    creds = FakeCredentials(expired=True)
+    client = Client(credentials=creds, api_key="test-api-key")
+
+
+@mock.patch.object(httpx.Client, "send", autospec=True)
+def test_refresh_credentials_mldev(mock_send):
+  creds = FakeCredentials(expired=True)
+  client = Client(credentials=creds)
+  mock_send.return_value = httpx.Response(
+      status_code=200,
+      json={"candidates": [{"content": {"parts": [{"text": "response"}]}}]},
+  )
+  client.models.generate_content(model="test", contents="hello?")
+  mock_send.assert_called_once()
+  request = mock_send.call_args[0][1]
+  assert "Authorization" in request.headers
+  assert request.headers["Authorization"] == "Bearer refreshed_token"
+  assert "x-goog-api-key" not in request.headers
+  assert creds.refresh_count == 1
+
+
+@requires_aiohttp
+@pytest.mark.asyncio
+@mock.patch.object(httpx.AsyncClient, "send", autospec=True)
+async def test_async_refresh_credentials_mldev(mock_send):
+  creds = FakeCredentials(expired=True)
+  client = Client(credentials=creds)
+  mock_send.return_value = httpx.Response(
+      status_code=200,
+      json={"candidates": [{"content": {"parts": [{"text": "response"}]}}]},
+  )
+  await client.aio.models.generate_content(model="test", contents="hello?")
+  mock_send.assert_called_once()
+  request = mock_send.call_args[0][1]
+  assert "Authorization" in request.headers
+  assert request.headers["Authorization"] == "Bearer refreshed_token"
+  assert "x-goog-api-key" not in request.headers
+  assert creds.refresh_count == 1