feat!: standardize base_url for inference (#4177)

# What does this PR do?

Completes #3732 by removing runtime URL transformations and requiring
users to provide full URLs in configuration. All providers now use
'base_url' consistently and respect the exact URL provided without
appending paths like /v1 or /openai/v1 at runtime.

BREAKING CHANGE: Users must update configs to include full URL paths
(e.g., http://localhost:11434/v1 instead of http://localhost:11434).

Closes #3732 

## Test Plan

Existing tests should pass even with the URL changes, due to default
URLs being altered.

Add unit test to enforce URL standardization across remote inference
providers (verifies all use 'base_url' field with HttpUrl | None type)

Signed-off-by: Charlie Doern <cdoern@redhat.com>

tests/unit/providers/inference/test_inference_client_caching.py

@@ -120,7 +120,7 @@ from llama_stack.providers.remote.inference.watsonx.watsonx import WatsonXInfere
             VLLMInferenceAdapter,
             "llama_stack.providers.remote.inference.vllm.VLLMProviderDataValidator",
             {
-                "url": "http://fake",
+                "base_url": "http://fake",
             },
         ),
     ],
@@ -153,7 +153,7 @@ def test_litellm_provider_data_used(config_cls, adapter_cls, provider_data_valid
     """Validate data for LiteLLM-based providers.  Similar to test_openai_provider_data_used, but without the
     assumption that there is an OpenAI-compatible client object."""
 
-    inference_adapter = adapter_cls(config=config_cls())
+    inference_adapter = adapter_cls(config=config_cls(base_url="http://fake"))
 
     inference_adapter.__provider_spec__ = MagicMock()
     inference_adapter.__provider_spec__.provider_data_validator = provider_data_validator

tests/unit/providers/inference/test_remote_vllm.py

@@ -40,7 +40,7 @@ from llama_stack_api import (
 
 @pytest.fixture(scope="function")
 async def vllm_inference_adapter():
-    config = VLLMInferenceAdapterConfig(url="http://mocked.localhost:12345")
+    config = VLLMInferenceAdapterConfig(base_url="http://mocked.localhost:12345")
     inference_adapter = VLLMInferenceAdapter(config=config)
     inference_adapter.model_store = AsyncMock()
     await inference_adapter.initialize()
@@ -204,7 +204,7 @@ async def test_vllm_completion_extra_body():
     via extra_body to the underlying OpenAI client through the InferenceRouter.
     """
     # Set up the vLLM adapter
-    config = VLLMInferenceAdapterConfig(url="http://mocked.localhost:12345")
+    config = VLLMInferenceAdapterConfig(base_url="http://mocked.localhost:12345")
     vllm_adapter = VLLMInferenceAdapter(config=config)
     vllm_adapter.__provider_id__ = "vllm"
     await vllm_adapter.initialize()
@@ -277,7 +277,7 @@ async def test_vllm_chat_completion_extra_body():
     via extra_body to the underlying OpenAI client through the InferenceRouter for chat completion.
     """
     # Set up the vLLM adapter
-    config = VLLMInferenceAdapterConfig(url="http://mocked.localhost:12345")
+    config = VLLMInferenceAdapterConfig(base_url="http://mocked.localhost:12345")
     vllm_adapter = VLLMInferenceAdapter(config=config)
     vllm_adapter.__provider_id__ = "vllm"
     await vllm_adapter.initialize()

tests/unit/providers/nvidia/test_rerank_inference.py

@@ -146,7 +146,7 @@ async def test_hosted_model_not_in_endpoint_mapping():
 
 async def test_self_hosted_ignores_endpoint():
     adapter = create_adapter(
-        config=NVIDIAConfig(url="http://localhost:8000", api_key=None),
+        config=NVIDIAConfig(base_url="http://localhost:8000", api_key=None),
         rerank_endpoints={"test-model": "https://model.endpoint/rerank"},  # This should be ignored for self-hosted.
     )
     mock_session = MockSession(MockResponse())

tests/unit/providers/test_configs.py

@@ -4,8 +4,10 @@
 # This source code is licensed under the terms described in the LICENSE file in
 # the root directory of this source tree.
 
+from typing import get_args, get_origin
+
 import pytest
-from pydantic import BaseModel
+from pydantic import BaseModel, HttpUrl
 
 from llama_stack.core.distribution import get_provider_registry, providable_apis
 from llama_stack.core.utils.dynamic import instantiate_class_type
@@ -41,3 +43,55 @@ class TestProviderConfigurations:
 
         sample_config = config_type.sample_run_config(__distro_dir__="foobarbaz")
         assert isinstance(sample_config, dict), f"{config_class_name}.sample_run_config() did not return a dict"
+
+    def test_remote_inference_url_standardization(self):
+        """Verify all remote inference providers use standardized base_url configuration."""
+        provider_registry = get_provider_registry()
+        inference_providers = provider_registry.get("inference", {})
+
+        # Filter for remote providers only
+        remote_providers = {k: v for k, v in inference_providers.items() if k.startswith("remote::")}
+
+        failures = []
+        for provider_type, provider_spec in remote_providers.items():
+            try:
+                config_class_name = provider_spec.config_class
+                config_type = instantiate_class_type(config_class_name)
+
+                # Check that config has base_url field (not url)
+                if hasattr(config_type, "model_fields"):
+                    fields = config_type.model_fields
+
+                    # Should NOT have 'url' field (old pattern)
+                    if "url" in fields:
+                        failures.append(
+                            f"{provider_type}: Uses deprecated 'url' field instead of 'base_url'. "
+                            f"Please rename to 'base_url' for consistency."
+                        )
+
+                    # Should have 'base_url' field with HttpUrl | None type
+                    if "base_url" in fields:
+                        field_info = fields["base_url"]
+                        annotation = field_info.annotation
+
+                        # Check if it's HttpUrl or HttpUrl | None
+                        # get_origin() returns Union for (X | Y), None for plain types
+                        # get_args() returns the types inside Union, e.g. (HttpUrl, NoneType)
+                        is_valid = False
+                        if get_origin(annotation) is not None:  # It's a Union/Optional
+                            if HttpUrl in get_args(annotation):
+                                is_valid = True
+                        elif annotation == HttpUrl:  # Plain HttpUrl without | None
+                            is_valid = True
+
+                        if not is_valid:
+                            failures.append(
+                                f"{provider_type}: base_url field has incorrect type annotation. "
+                                f"Expected 'HttpUrl | None', got '{annotation}'"
+                            )
+
+            except Exception as e:
+                failures.append(f"{provider_type}: Error checking URL standardization: {str(e)}")
+
+        if failures:
+            pytest.fail("URL standardization violations found:\n" + "\n".join(f"  - {f}" for f in failures))