feat!: standardize base_url for inference

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.

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

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

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

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))