Add attempted-retries and timeout values to response headers + more testing (#7926)

* feat(router.py): add retry headers to response

makes it easy to add testing to ensure model-specific retries are respected

* fix(add_retry_headers.py): clarify attempted retries vs. max retries

* test(test_fallbacks.py): add test for checking if max retries set for model is respected

* test(test_fallbacks.py): assert values for attempted retries and max retries are as expected

* fix(utils.py): return timeout in litellm proxy response headers

* test(test_fallbacks.py): add test to assert model specific timeout used on timeout error

* test: add bad model with timeout to proxy

* fix: fix linting error

* fix(router.py): fix get model list from model alias

* test: loosen test restriction - account for other events on proxy

litellm/utils.py

@@ -669,6 +669,7 @@ def _get_wrapper_num_retries(
     Get the number of retries from the kwargs and the retry policy.
     Used for the wrapper functions.
     """
+
     num_retries = kwargs.get("num_retries", None)
     if num_retries is None:
         num_retries = litellm.num_retries
@@ -684,6 +685,21 @@ def _get_wrapper_num_retries(
     return num_retries, kwargs
 
 
+def _get_wrapper_timeout(
+    kwargs: Dict[str, Any], exception: Exception
+) -> Optional[Union[float, int, httpx.Timeout]]:
+    """
+    Get the timeout from the kwargs
+    Used for the wrapper functions.
+    """
+
+    timeout = cast(
+        Optional[Union[float, int, httpx.Timeout]], kwargs.get("timeout", None)
+    )
+
+    return timeout
+
+
 def client(original_function):  # noqa: PLR0915
     rules_obj = Rules()
 
@@ -1243,9 +1259,11 @@ def client(original_function):  # noqa: PLR0915
                 _is_litellm_router_call = "model_group" in kwargs.get(
                     "metadata", {}
                 )  # check if call from litellm.router/proxy
+
                 if (
                     num_retries and not _is_litellm_router_call
                 ):  # only enter this if call is not from litellm router/proxy. router has it's own logic for retrying
+
                     try:
                         litellm.num_retries = (
                             None  # set retries to None to prevent infinite loops
@@ -1266,6 +1284,7 @@ def client(original_function):  # noqa: PLR0915
                     and context_window_fallback_dict
                     and model in context_window_fallback_dict
                 ):
+
                     if len(args) > 0:
                         args[0] = context_window_fallback_dict[model]  # type: ignore
                     else:
@@ -1275,6 +1294,9 @@ def client(original_function):  # noqa: PLR0915
             setattr(
                 e, "num_retries", num_retries
             )  ## IMPORTANT: returns the deployment's num_retries to the router
+
+            timeout = _get_wrapper_timeout(kwargs=kwargs, exception=e)
+            setattr(e, "timeout", timeout)
             raise e
 
     is_coroutine = inspect.iscoroutinefunction(original_function)