fix: Vertex AI image edit credential source

litellm/llms/vertex_ai/image_edit/vertex_gemini_transformation.py

@@ -8,7 +8,6 @@ import httpx
 from httpx._types import RequestFiles
 
 import litellm
-
 from litellm.images.utils import ImageEditRequestUtils
 from litellm.llms.base_llm.image_edit.transformation import BaseImageEditConfig
 from litellm.llms.vertex_ai.gemini.vertex_and_google_ai_studio_gemini import VertexLLM
@@ -94,10 +93,22 @@ class VertexAIGeminiImageEditConfig(BaseImageEditConfig, VertexLLM):
         headers: dict,
         model: str,
         api_key: Optional[str] = None,
+        litellm_params: Optional[dict] = None,
+        api_base: Optional[str] = None,
     ) -> dict:
         headers = headers or {}
-        vertex_project = self._resolve_vertex_project()
-        vertex_credentials = self._resolve_vertex_credentials()
+        litellm_params = litellm_params or {}
+        
+        # If a custom api_base is provided, skip credential validation
+        # This allows users to use proxies or mock endpoints without needing Vertex AI credentials
+        _api_base = litellm_params.get("api_base") or api_base
+        if _api_base is not None:
+            return headers
+        
+        # First check litellm_params (where vertex_ai_project/vertex_ai_credentials are passed)
+        # then fall back to environment variables and other sources
+        vertex_project = self.safe_get_vertex_ai_project(litellm_params) or self._resolve_vertex_project()
+        vertex_credentials = self.safe_get_vertex_ai_credentials(litellm_params) or self._resolve_vertex_credentials()
         access_token, _ = self._ensure_access_token(
             credentials=vertex_credentials,
             project_id=vertex_project,
@@ -114,19 +125,27 @@ class VertexAIGeminiImageEditConfig(BaseImageEditConfig, VertexLLM):
         """
         Get the complete URL for Vertex AI Gemini generateContent API
         """
-        vertex_project = self._resolve_vertex_project()
-        vertex_location = self._resolve_vertex_location()
-
-        if not vertex_project or not vertex_location:
-            raise ValueError("vertex_project and vertex_location are required for Vertex AI")
-
         # Use the model name as provided, handling vertex_ai prefix
         model_name = model
         if model.startswith("vertex_ai/"):
             model_name = model.replace("vertex_ai/", "")
 
+        # If a custom api_base is provided, use it directly
+        # This allows users to use proxies or mock endpoints
         if api_base:
-            base_url = api_base.rstrip("/")
+            return api_base.rstrip("/")
+
+        # First check litellm_params (where vertex_ai_project/vertex_ai_location are passed)
+        # then fall back to environment variables and other sources
+        vertex_project = self.safe_get_vertex_ai_project(litellm_params) or self._resolve_vertex_project()
+        vertex_location = self.safe_get_vertex_ai_location(litellm_params) or self._resolve_vertex_location()
+
+        if not vertex_project or not vertex_location:
+            raise ValueError("vertex_project and vertex_location are required for Vertex AI")
+
+        # Handle global location differently (no region prefix in URL)
+        if vertex_location == "global":
+            base_url = "https://aiplatform.googleapis.com"
         else:
             base_url = f"https://{vertex_location}-aiplatform.googleapis.com"
 

tests/test_litellm/llms/vertex_ai/image_edit/test_vertex_ai_image_edit_transformation.py

@@ -140,6 +140,31 @@ class TestVertexAIGeminiImageEditTransformation:
                 headers={},
             )
 
+    def test_validate_environment_with_litellm_params(self) -> None:
+        """Test validate_environment uses credentials from litellm_params"""
+        with patch.object(
+            self.config, "_ensure_access_token", return_value=("test-token", "test-expiry")
+        ) as mock_token:
+            with patch.object(self.config, "set_headers", return_value={"Authorization": "Bearer test-token"}) as mock_headers:
+                litellm_params = {
+                    "vertex_ai_project": "custom-project",
+                    "vertex_ai_credentials": "/path/to/custom/credentials.json",
+                }
+
+                result = self.config.validate_environment(
+                    headers={"X-Custom": "header"},
+                    model=self.model,
+                    litellm_params=litellm_params,
+                    api_base=None,
+                )
+
+                # Verify that safe_get_vertex_ai_project and safe_get_vertex_ai_credentials were used
+                mock_token.assert_called_once()
+                call_kwargs = mock_token.call_args[1]
+                assert call_kwargs["credentials"] == "/path/to/custom/credentials.json"
+                assert call_kwargs["project_id"] == "custom-project"
+                assert result == {"Authorization": "Bearer test-token"}
+
 
 class TestVertexAIImagenImageEditTransformation:
     def setup_method(self) -> None: