feat: Add open ai compatible moderations api

llama_stack/core/routers/safety.py

@@ -10,6 +10,7 @@ from llama_stack.apis.inference import (
     Message,
 )
 from llama_stack.apis.safety import RunShieldResponse, Safety
+from llama_stack.apis.safety.safety import ModerationObject
 from llama_stack.apis.shields import Shield
 from llama_stack.log import get_logger
 from llama_stack.providers.datatypes import RoutingTable
@@ -60,3 +61,24 @@ class SafetyRouter(Safety):
             messages=messages,
             params=params,
         )
+
+    async def create(self, input: str | list[str], model: str) -> ModerationObject:
+        async def get_shield_id(self, model: str) -> str:
+            """Get Shield id from model (provider_resource_id) of shield."""
+            list_shields_response = await self.routing_table.list_shields()
+
+            matches = [s.identifier for s in list_shields_response.data if model == s.provider_resource_id]
+            if not matches:
+                raise ValueError(f"No shield associated with provider_resource id {model}")
+            if len(matches) > 1:
+                raise ValueError(f"Multiple shields associated with provider_resource id {model}")
+            return matches[0]
+
+        shield_id = await get_shield_id(self, model)
+        logger.debug(f"SafetyRouter.create: {shield_id}")
+        provider = await self.routing_table.get_provider_impl(shield_id)
+
+        return await provider.create(
+            input=input,
+            model=model,
+        )