Somewhat better error handling

llama_stack/distribution/server/server.py

@@ -35,6 +35,9 @@ from fastapi import Body, FastAPI, HTTPException, Request, Response
 from fastapi.exceptions import RequestValidationError
 from fastapi.responses import JSONResponse, StreamingResponse
 from fastapi.routing import APIRoute
+from pydantic import BaseModel, ValidationError
+from termcolor import cprint
+from typing_extensions import Annotated
 
 from llama_stack.providers.utils.telemetry.tracing import (
     end_trace,
@@ -42,9 +45,6 @@ from llama_stack.providers.utils.telemetry.tracing import (
     SpanStatus,
     start_trace,
 )
-from pydantic import BaseModel, ValidationError
-from termcolor import cprint
-from typing_extensions import Annotated
 from llama_stack.distribution.datatypes import *  # noqa: F403
 
 from llama_stack.distribution.distribution import (
@@ -90,10 +90,35 @@ async def global_exception_handler(request: Request, exc: Exception):
 
 def translate_exception(exc: Exception) -> HTTPException:
     if isinstance(exc, ValidationError):
-        return RequestValidationError(exc.raw_errors)
+        exc = RequestValidationError(exc.raw_errors)
 
-    # Add more custom exception translations here
-    return HTTPException(status_code=500, detail="Internal server error")
+    if isinstance(exc, RequestValidationError):
+        return HTTPException(
+            status_code=400,
+            detail={
+                "errors": [
+                    {
+                        "loc": list(error["loc"]),
+                        "msg": error["msg"],
+                        "type": error["type"],
+                    }
+                    for error in exc.errors()
+                ]
+            },
+        )
+    elif isinstance(exc, ValueError):
+        return HTTPException(status_code=400, detail=f"Invalid value: {str(exc)}")
+    elif isinstance(exc, PermissionError):
+        return HTTPException(status_code=403, detail=f"Permission denied: {str(exc)}")
+    elif isinstance(exc, TimeoutError):
+        return HTTPException(status_code=504, detail=f"Operation timed out: {str(exc)}")
+    elif isinstance(exc, NotImplementedError):
+        return HTTPException(status_code=501, detail=f"Not implemented: {str(exc)}")
+    else:
+        return HTTPException(
+            status_code=500,
+            detail="Internal server error: An unexpected error occurred.",
+        )
 
 
 async def passthrough(