feat: Add allow_listing_models

• Add allow_listing_models configuration flag to VLLM provider to control model listing behavior
• Implement allow_listing_models() method across all providers with default implementations in base classes
• Prevent HTTP requests to /v1/models endpoint when allow_listing_models=false for improved security and performance
• Fix unit tests to include allow_listing_models method in test classes and mock objects

tests/unit/providers/inference/test_remote_vllm.py

@@ -636,27 +636,75 @@ async def test_should_refresh_models():
     Test the should_refresh_models method with different refresh_models configurations.
 
     This test verifies that:
-    1. When refresh_models is True, should_refresh_models returns True regardless of api_token
-    2. When refresh_models is False, should_refresh_models returns False regardless of api_token
+    1. When refresh_models is True, should_refresh_models returns True
+    2. When refresh_models is False, should_refresh_models returns False
     """
 
-    # Test case 1: refresh_models is True, api_token is None
-    config1 = VLLMInferenceAdapterConfig(url="http://test.localhost", api_token=None, refresh_models=True)
+    # Test case 1: refresh_models is True
+    config1 = VLLMInferenceAdapterConfig(url="http://test.localhost", refresh_models=True)
     adapter1 = VLLMInferenceAdapter(config1)
     result1 = await adapter1.should_refresh_models()
     assert result1 is True, "should_refresh_models should return True when refresh_models is True"
 
-    # Test case 2: refresh_models is True, api_token is empty string
-    config2 = VLLMInferenceAdapterConfig(url="http://test.localhost", api_token="", refresh_models=True)
+    # Test case 2: refresh_models is False
+    config2 = VLLMInferenceAdapterConfig(url="http://test.localhost", refresh_models=False)
     adapter2 = VLLMInferenceAdapter(config2)
     result2 = await adapter2.should_refresh_models()
-    assert result2 is True, "should_refresh_models should return True when refresh_models is True"
+    assert result2 is False, "should_refresh_models should return False when refresh_models is False"
 
-    # Test case 3: refresh_models is True, api_token is "fake" (default)
-    config3 = VLLMInferenceAdapterConfig(url="http://test.localhost", api_token="fake", refresh_models=True)
+
+async def test_allow_listing_models_flag():
+    """
+    Test the allow_listing_models flag functionality.
+
+    This test verifies that:
+    1. When allow_listing_models is True (default), list_models returns models from the server
+    2. When allow_listing_models is False, list_models returns None without calling the server
+    """
+
+    # Test case 1: allow_listing_models is True (default)
+    config1 = VLLMInferenceAdapterConfig(url="http://test.localhost", allow_listing_models=True)
+    adapter1 = VLLMInferenceAdapter(config1)
+    adapter1.__provider_id__ = "test-vllm"
+
+    # Mock the client.models.list() method
+    with patch.object(VLLMInferenceAdapter, "client", new_callable=PropertyMock) as mock_client_property:
+        mock_client = MagicMock()
+
+        async def mock_models_list():
+            yield OpenAIModel(id="test-model-1", created=1, object="model", owned_by="test")
+            yield OpenAIModel(id="test-model-2", created=2, object="model", owned_by="test")
+
+        mock_client.models.list.return_value = mock_models_list()
+        mock_client_property.return_value = mock_client
+
+        models = await adapter1.list_models()
+        assert models is not None, "list_models should return models when allow_listing_models is True"
+        assert len(models) == 2, "Should return 2 models"
+        assert models[0].identifier == "test-model-1"
+        assert models[1].identifier == "test-model-2"
+        mock_client.models.list.assert_called_once()
+
+    # Test case 2: allow_listing_models is False
+    config2 = VLLMInferenceAdapterConfig(url="http://test.localhost", allow_listing_models=False)
+    adapter2 = VLLMInferenceAdapter(config2)
+    adapter2.__provider_id__ = "test-vllm"
+
+    # Mock the client.models.list() method
+    with patch.object(VLLMInferenceAdapter, "client", new_callable=PropertyMock) as mock_client_property:
+        mock_client = MagicMock()
+        mock_client_property.return_value = mock_client
+
+        models = await adapter2.list_models()
+        assert models is None, "list_models should return None when allow_listing_models is False"
+        mock_client.models.list.assert_not_called()
+
+    # Test case 3: allow_listing_models defaults to True
+    config3 = VLLMInferenceAdapterConfig(url="http://test.localhost")
     adapter3 = VLLMInferenceAdapter(config3)
-    result3 = await adapter3.should_refresh_models()
-    assert result3 is True, "should_refresh_models should return True when refresh_models is True"
+    adapter3.__provider_id__ = "test-vllm"
+    result3 = await adapter3.allow_listing_models()
+    assert result3 is True, "allow_listing_models should return True by default"
 
     # Test case 4: refresh_models is True, api_token is real token
     config4 = VLLMInferenceAdapterConfig(url="http://test.localhost", api_token="real-token-123", refresh_models=True)
@@ -670,6 +718,22 @@ async def test_should_refresh_models():
     result5 = await adapter5.should_refresh_models()
     assert result5 is False, "should_refresh_models should return False when refresh_models is False"
 
+    # Mock the client.models.list() method
+    with patch.object(VLLMInferenceAdapter, "client", new_callable=PropertyMock) as mock_client_property:
+        mock_client = MagicMock()
+
+        async def mock_models_list():
+            yield OpenAIModel(id="default-model", created=1, object="model", owned_by="test")
+
+        mock_client.models.list.return_value = mock_models_list()
+        mock_client_property.return_value = mock_client
+
+        models = await adapter3.list_models()
+        assert models is not None, "list_models should return models when allow_listing_models defaults to True"
+        assert len(models) == 1, "Should return 1 model"
+        assert models[0].identifier == "default-model"
+        mock_client.models.list.assert_called_once()
+
 
 async def test_provider_data_var_context_propagation(vllm_inference_adapter):
     """