From 400b8289f744c4b8cdaa2c35268192c23e90d26c Mon Sep 17 00:00:00 2001
From: Woosuk Kwon <woosuk.kwon@berkeley.edu>
Date: Mon, 18 Sep 2023 22:36:17 -0700
Subject: [PATCH] Add pyarrow to dependencies & Print warning on Ray import
 error (#1094)

---
 requirements.txt         | 1 +
 vllm/engine/ray_utils.py | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/requirements.txt b/requirements.txt
index bb65f440de0ae..bb189fcb47e6f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,6 +2,7 @@ ninja  # For faster builds.
 psutil
 ray >= 2.5.1
 pandas  # Required for Ray data.
+pyarrow  # Required for Ray data.
 sentencepiece  # Required for LLaMA tokenizer.
 numpy
 torch >= 2.0.0
diff --git a/vllm/engine/ray_utils.py b/vllm/engine/ray_utils.py
index 2982f0f91febe..80479967cc62f 100644
--- a/vllm/engine/ray_utils.py
+++ b/vllm/engine/ray_utils.py
@@ -2,6 +2,9 @@ import socket
 from typing import Optional, Tuple, TYPE_CHECKING
 
 from vllm.config import ParallelConfig
+from vllm.logger import init_logger
+
+logger = init_logger(__name__)
 
 try:
     import ray
@@ -28,7 +31,10 @@ try:
             executor = getattr(self, method)
             return executor(*args, **kwargs)
 
-except ImportError:
+except ImportError as e:
+    logger.warning(f"Failed to import Ray with {e!r}. "
+                   "For distributed inference, please install Ray with "
+                   "`pip install ray pandas pyarrow`.")
     ray = None
     TorchDistributedWorker = None
     RayWorker = None  # pylint: disable=invalid-name