chore: import upstream snapshot with attribution

backend/python/common/vllm_utils.py

@@ -0,0 +1,43 @@
+"""vLLM-specific helpers for the vllm and vllm-omni gRPC backends.
+
+Generic helpers (``parse_options``, ``messages_to_dicts``) live in
+``python_utils`` and are re-exported here for backwards compatibility with
+existing imports in both backends.
+"""
+import sys
+
+from python_utils import messages_to_dicts, parse_options
+
+__all__ = ["parse_options", "messages_to_dicts", "setup_parsers"]
+
+
+def setup_parsers(opts):
+    """Return ``(tool_parser_cls, reasoning_parser_cls)`` from an opts dict.
+
+    Uses vLLM's native ``ToolParserManager`` / ``ReasoningParserManager``.
+    Returns ``(None, None)`` if vLLM isn't installed or the requested
+    parser name can't be resolved.
+    """
+    tool_parser_cls = None
+    reasoning_parser_cls = None
+
+    tool_parser_name = opts.get("tool_parser")
+    reasoning_parser_name = opts.get("reasoning_parser")
+
+    if tool_parser_name:
+        try:
+            from vllm.tool_parsers import ToolParserManager
+            tool_parser_cls = ToolParserManager.get_tool_parser(tool_parser_name)
+            print(f"[vllm_utils] Loaded tool_parser: {tool_parser_name}", file=sys.stderr)
+        except Exception as e:
+            print(f"[vllm_utils] Failed to load tool_parser {tool_parser_name}: {e}", file=sys.stderr)
+
+    if reasoning_parser_name:
+        try:
+            from vllm.reasoning import ReasoningParserManager
+            reasoning_parser_cls = ReasoningParserManager.get_reasoning_parser(reasoning_parser_name)
+            print(f"[vllm_utils] Loaded reasoning_parser: {reasoning_parser_name}", file=sys.stderr)
+        except Exception as e:
+            print(f"[vllm_utils] Failed to load reasoning_parser {reasoning_parser_name}: {e}", file=sys.stderr)
+
+    return tool_parser_cls, reasoning_parser_cls