fix: reuse cached credentials in VertexAIPartnerModels (#26065)

* fix: reuse cached credentials in VertexAIPartnerModels instead of creating new VertexLLM per request

VertexAIPartnerModels.completion() was creating a throwaway VertexLLM()
instance on every call to get an access token, bypassing the credential
cache inherited from VertexBase. This caused a fresh token fetch for
every single request, adding significant latency overhead.

Fix: call super().__init__() to initialize VertexBase's credential cache,
and use self._ensure_access_token() instead of a new VertexLLM instance.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: apply same credential caching fix to VertexAIGemmaModels and VertexAIModelGardenModels

Same bug as VertexAIPartnerModels: both classes had `pass` in __init__
instead of `super().__init__()`, and created throwaway VertexLLM()
instances per request instead of using self._ensure_access_token().

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
Matthew Lapointe 2026-04-21 20:09:58 -07:00 committed by GitHub
parent 4583310313
commit 67e6a95cb0
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4 changed files with 226 additions and 19 deletions

View file

@ -45,7 +45,7 @@ class PartnerModelPrefixes(str, Enum):
class VertexAIPartnerModels(VertexBase):
def __init__(self) -> None:
pass
super().__init__()
@staticmethod
def is_vertex_partner_model(model: str):
@ -116,9 +116,6 @@ class VertexAIPartnerModels(VertexBase):
CodestralTextCompletion,
)
from litellm.llms.openai_like.chat.handler import OpenAILikeChatHandler
from litellm.llms.vertex_ai.gemini.vertex_and_google_ai_studio_gemini import (
VertexLLM,
)
except Exception as e:
raise VertexAIError(
status_code=400,
@ -133,9 +130,7 @@ class VertexAIPartnerModels(VertexBase):
message="""Upgrade vertex ai. Run `pip install "google-cloud-aiplatform>=1.38"`""",
)
try:
vertex_httpx_logic = VertexLLM()
access_token, project_id = vertex_httpx_logic._ensure_access_token(
access_token, project_id = self._ensure_access_token(
credentials=vertex_credentials,
project_id=vertex_project,
custom_llm_provider="vertex_ai",

View file

@ -31,7 +31,7 @@ from ..vertex_llm_base import VertexBase
class VertexAIGemmaModels(VertexBase):
def __init__(self) -> None:
pass
super().__init__()
def completion(
self,
@ -62,9 +62,6 @@ class VertexAIGemmaModels(VertexBase):
try:
import vertexai
from litellm.llms.vertex_ai.gemini.vertex_and_google_ai_studio_gemini import (
VertexLLM,
)
from litellm.llms.vertex_ai.vertex_gemma_models.transformation import (
VertexGemmaConfig,
)
@ -83,9 +80,8 @@ class VertexAIGemmaModels(VertexBase):
)
try:
model = get_vertex_base_model_name(model=model)
vertex_httpx_logic = VertexLLM()
access_token, project_id = vertex_httpx_logic._ensure_access_token(
access_token, project_id = self._ensure_access_token(
credentials=vertex_credentials,
project_id=vertex_project,
custom_llm_provider="vertex_ai",

View file

@ -41,7 +41,7 @@ def create_vertex_url(
class VertexAIModelGardenModels(VertexBase):
def __init__(self) -> None:
pass
super().__init__()
def completion(
self,
@ -73,9 +73,6 @@ class VertexAIModelGardenModels(VertexBase):
import vertexai
from litellm.llms.openai_like.chat.handler import OpenAILikeChatHandler
from litellm.llms.vertex_ai.gemini.vertex_and_google_ai_studio_gemini import (
VertexLLM,
)
except Exception as e:
raise VertexAIError(
status_code=400,
@ -91,9 +88,8 @@ class VertexAIModelGardenModels(VertexBase):
)
try:
model = get_vertex_base_model_name(model=model)
vertex_httpx_logic = VertexLLM()
access_token, project_id = vertex_httpx_logic._ensure_access_token(
access_token, project_id = self._ensure_access_token(
credentials=vertex_credentials,
project_id=vertex_project,
custom_llm_provider="vertex_ai",

View file

@ -0,0 +1,220 @@
"""
Test that VertexBase subclasses (PartnerModels, Gemma, ModelGarden) reuse
cached credentials instead of creating a new VertexLLM instance on every request.
"""
import sys
from unittest.mock import MagicMock, patch
import pytest
from litellm.llms.vertex_ai.vertex_ai_partner_models.main import (
VertexAIPartnerModels,
)
from litellm.llms.vertex_ai.vertex_gemma_models.main import VertexAIGemmaModels
from litellm.llms.vertex_ai.vertex_model_garden.main import VertexAIModelGardenModels
def _mock_vertexai():
"""Return a MagicMock that satisfies the vertexai import guards."""
m = MagicMock()
m.preview = MagicMock()
m.preview.language_models = MagicMock()
return m
class TestVertexBaseSubclassInit:
"""All VertexBase subclasses must call super().__init__() so that
the credential cache is initialized."""
@pytest.mark.parametrize(
"cls",
[VertexAIPartnerModels, VertexAIGemmaModels, VertexAIModelGardenModels],
ids=["PartnerModels", "Gemma", "ModelGarden"],
)
def test_init_calls_super(self, cls):
instance = cls()
assert hasattr(instance, "_credentials_project_mapping")
assert isinstance(instance._credentials_project_mapping, dict)
assert hasattr(instance, "access_token")
assert hasattr(instance, "project_id")
class TestPartnerModelsCredentialReuse:
def test_completion_uses_self_ensure_access_token(self):
"""completion() should call self._ensure_access_token, not create a
throwaway VertexLLM instance."""
partner = VertexAIPartnerModels()
with (
patch.dict(sys.modules, {"vertexai": _mock_vertexai()}),
patch.object(
partner,
"_ensure_access_token",
return_value=("cached-token", "test-project"),
) as mock_ensure,
patch(
"litellm.llms.vertex_ai.vertex_ai_partner_models.main.base_llm_http_handler"
) as mock_handler,
):
mock_handler.completion.return_value = "response"
partner.completion(
model="meta/llama-3.1-405b-instruct-maas",
messages=[{"role": "user", "content": "hello"}],
model_response=MagicMock(),
print_verbose=lambda *a, **kw: None,
encoding=MagicMock(),
logging_obj=MagicMock(),
api_base=None,
optional_params={},
custom_prompt_dict={},
headers=None,
timeout=30.0,
litellm_params={},
vertex_project="test-project",
vertex_location="us-central1",
vertex_credentials='{"type": "service_account"}',
)
mock_ensure.assert_called_once_with(
credentials='{"type": "service_account"}',
project_id="test-project",
custom_llm_provider="vertex_ai",
)
def test_credential_cache_shared_across_calls(self):
"""Two successive completion() calls should hit load_auth only once."""
partner = VertexAIPartnerModels()
mock_creds = MagicMock()
mock_creds.token = "my-token"
mock_creds.expired = False
mock_creds.project_id = "proj"
mock_creds.quota_project_id = "proj"
with (
patch.dict(sys.modules, {"vertexai": _mock_vertexai()}),
patch.object(
partner, "load_auth", return_value=(mock_creds, "proj")
) as mock_load,
patch(
"litellm.llms.vertex_ai.vertex_ai_partner_models.main.base_llm_http_handler"
) as mock_handler,
):
mock_handler.completion.return_value = "resp"
common_kwargs = dict(
model="meta/llama-3.1-405b-instruct-maas",
messages=[{"role": "user", "content": "hi"}],
model_response=MagicMock(),
print_verbose=lambda *a, **kw: None,
encoding=MagicMock(),
logging_obj=MagicMock(),
api_base=None,
optional_params={},
custom_prompt_dict={},
headers=None,
timeout=30.0,
litellm_params={},
vertex_project="proj",
vertex_location="us-central1",
vertex_credentials='{"type": "service_account"}',
)
partner.completion(**common_kwargs)
partner.completion(**common_kwargs)
assert mock_load.call_count == 1
class TestGemmaModelsCredentialReuse:
def test_completion_uses_self_ensure_access_token(self):
"""completion() should call self._ensure_access_token, not create a
throwaway VertexLLM instance."""
gemma = VertexAIGemmaModels()
mock_gemma_config = MagicMock()
mock_gemma_config.return_value.completion.return_value = "response"
with (
patch.dict(sys.modules, {"vertexai": _mock_vertexai()}),
patch.object(
gemma,
"_ensure_access_token",
return_value=("cached-token", "test-project"),
) as mock_ensure,
patch(
"litellm.llms.vertex_ai.vertex_gemma_models.transformation.VertexGemmaConfig",
mock_gemma_config,
),
):
gemma.completion(
model="gemma/gemma-3-12b-it-1234567890",
messages=[{"role": "user", "content": "hello"}],
model_response=MagicMock(),
print_verbose=lambda *a, **kw: None,
encoding=MagicMock(),
logging_obj=MagicMock(),
api_base="https://123.us-central1-1.prediction.vertexai.goog/v1/projects/proj/locations/us-central1/endpoints/456:predict",
optional_params={},
custom_prompt_dict={},
headers=None,
timeout=30.0,
litellm_params={},
vertex_project="test-project",
vertex_location="us-central1",
vertex_credentials='{"type": "service_account"}',
)
mock_ensure.assert_called_once_with(
credentials='{"type": "service_account"}',
project_id="test-project",
custom_llm_provider="vertex_ai",
)
class TestModelGardenCredentialReuse:
def test_completion_uses_self_ensure_access_token(self):
"""completion() should call self._ensure_access_token, not create a
throwaway VertexLLM instance."""
garden = VertexAIModelGardenModels()
mock_handler = MagicMock()
mock_handler.return_value.completion.return_value = "response"
with (
patch.dict(sys.modules, {"vertexai": _mock_vertexai()}),
patch.object(
garden,
"_ensure_access_token",
return_value=("cached-token", "test-project"),
) as mock_ensure,
patch(
"litellm.llms.openai_like.chat.handler.OpenAILikeChatHandler",
mock_handler,
),
):
garden.completion(
model="openai/5464397967697903616",
messages=[{"role": "user", "content": "hello"}],
model_response=MagicMock(),
print_verbose=lambda *a, **kw: None,
encoding=MagicMock(),
logging_obj=MagicMock(),
api_base=None,
optional_params={},
custom_prompt_dict={},
headers=None,
timeout=30.0,
litellm_params={},
vertex_project="test-project",
vertex_location="us-central1",
vertex_credentials='{"type": "service_account"}',
)
mock_ensure.assert_called_once_with(
credentials='{"type": "service_account"}',
project_id="test-project",
custom_llm_provider="vertex_ai",
)