(feat) Vertex AI - add support for fine tuned embedding models (#6749)

* fix use fine tuned vertex embedding models

* test_vertex_embedding_url

* add _transform_openai_request_to_fine_tuned_embedding_request

* add _transform_openai_request_to_fine_tuned_embedding_request

* add transform_openai_request_to_vertex_embedding_request

* add _transform_vertex_response_to_openai_for_fine_tuned_models

* test_vertexai_embedding for ft models

* fix test_vertexai_embedding_finetuned

* doc fine tuned / custom embedding models

* fix test test_partner_models_httpx

tests/local_testing/test_amazing_vertex_completion.py

@@ -18,6 +18,8 @@ import json
 import os
 import tempfile
 from unittest.mock import AsyncMock, MagicMock, patch
+from respx import MockRouter
+import httpx
 
 import pytest
 
@@ -973,6 +975,7 @@ async def test_partner_models_httpx(model, sync_mode):
         data = {
             "model": model,
             "messages": messages,
+            "timeout": 10,
         }
         if sync_mode:
             response = litellm.completion(**data)
@@ -986,6 +989,8 @@ async def test_partner_models_httpx(model, sync_mode):
         assert isinstance(response._hidden_params["response_cost"], float)
     except litellm.RateLimitError as e:
         pass
+    except litellm.Timeout as e:
+        pass
     except litellm.InternalServerError as e:
         pass
     except Exception as e:
@@ -3051,3 +3056,70 @@ def test_custom_api_base(api_base):
         assert url == api_base + ":"
     else:
         assert url == test_endpoint
+
+
+@pytest.mark.asyncio
+@pytest.mark.respx
+async def test_vertexai_embedding_finetuned(respx_mock: MockRouter):
+    """
+    Tests that:
+    - Request URL and body are correctly formatted for Vertex AI embeddings
+    - Response is properly parsed into litellm's embedding response format
+    """
+    load_vertex_ai_credentials()
+    litellm.set_verbose = True
+
+    # Test input
+    input_text = ["good morning from litellm", "this is another item"]
+
+    # Expected request/response
+    expected_url = "https://us-central1-aiplatform.googleapis.com/v1/projects/633608382793/locations/us-central1/endpoints/1004708436694269952:predict"
+    expected_request = {
+        "instances": [
+            {"inputs": "good morning from litellm"},
+            {"inputs": "this is another item"},
+        ],
+        "parameters": {},
+    }
+
+    mock_response = {
+        "predictions": [
+            [[-0.000431762, -0.04416759, -0.03443353]],  # Truncated embedding vector
+            [[-0.000431762, -0.04416759, -0.03443353]],  # Truncated embedding vector
+        ],
+        "deployedModelId": "2275167734310371328",
+        "model": "projects/633608382793/locations/us-central1/models/snowflake-arctic-embed-m-long-1731622468876",
+        "modelDisplayName": "snowflake-arctic-embed-m-long-1731622468876",
+        "modelVersionId": "1",
+    }
+
+    # Setup mock request
+    mock_request = respx_mock.post(expected_url).mock(
+        return_value=httpx.Response(200, json=mock_response)
+    )
+
+    # Make request
+    response = await litellm.aembedding(
+        vertex_project="633608382793",
+        model="vertex_ai/1004708436694269952",
+        input=input_text,
+    )
+
+    # Assert request was made correctly
+    assert mock_request.called
+    request_body = json.loads(mock_request.calls[0].request.content)
+    print("\n\nrequest_body", request_body)
+    print("\n\nexpected_request", expected_request)
+    assert request_body == expected_request
+
+    # Assert response structure
+    assert response is not None
+    assert hasattr(response, "data")
+    assert len(response.data) == len(input_text)
+
+    # Assert embedding structure
+    for embedding in response.data:
+        assert "embedding" in embedding
+        assert isinstance(embedding["embedding"], list)
+        assert len(embedding["embedding"]) > 0
+        assert all(isinstance(x, float) for x in embedding["embedding"])