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brojs-task-69a474cdc46fd26f…/stream_agent.py
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2026-05-18 11:02:03 +00:00

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2.6 KiB
Python

from __future__ import annotations
import argparse
import os
from typing import Any
from langchain_core.messages import AIMessage
from langchain_core.tools import tool
from langchain_openai import ChatOpenAI
from langgraph.prebuilt import create_react_agent
@tool
def get_demo_price(product: str, city: str = "Казань") -> str:
"""Return a deterministic demo price for the requested product."""
prices = {
"молоко": "89 рублей",
"хлеб": "54 рубля",
"сыр": "219 рублей",
}
return f"{product} в городе {city}: {prices.get(product.lower(), 'цена не найдена')}"
def build_agent():
llm = ChatOpenAI(
model=os.getenv("OPENAI_MODEL", "openai/gpt-oss-20b:free"),
base_url=os.getenv("OPENAI_BASE_URL") or None,
api_key=os.getenv("OPENAI_API_KEY", "not-needed"),
temperature=0,
streaming=True,
)
return create_react_agent(llm, tools=[get_demo_price])
def format_message(message: AIMessage) -> str:
if message.content:
return str(message.content)
if message.tool_calls:
call = message.tool_calls[0]
return f"{call['name']}({call['args']})"
return ""
def format_chunk_message(chunk: tuple[Any, dict[str, Any]], state: dict[str, int]) -> None:
message, meta = chunk
current_step = int(meta.get("langgraph_step", state["step"]))
if current_step != state["step"]:
state["step"] = current_step
print("\n --- --- --- \n")
if getattr(message, "content", None):
print(message.content, end="", flush=True)
def run_stream(question: str) -> None:
agent = build_agent()
stream = agent.stream(
{"messages": [{"role": "human", "content": question}]},
stream_mode=["messages", "updates"],
)
state = {"step": 1}
for chunk_type, chunk_data in stream:
if chunk_type == "messages":
format_chunk_message(chunk_data, state)
elif chunk_type == "updates" and chunk_data.get("model"):
last_message = chunk_data["model"]["messages"][-1]
formatted = format_message(last_message)
if formatted:
print(f"\n{formatted}")
def main() -> None:
parser = argparse.ArgumentParser(description="Streaming AI-agent demo")
parser.add_argument("question", nargs="*", help="User question")
args = parser.parse_args()
question = " ".join(args.question).strip() or "Сколько стоит молоко и хлеб в Казани?"
run_stream(question)
if __name__ == "__main__":
main()