Update main.py with Ollama and LangGraph implementation

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"""main.py
Простой FAQ‑бот, использующий ChromaDB для локальных конспектов и один MCP‑подобный инструмент – HTTP‑запрос к статическому JSON.
Требования:
- Python 3.10+
- Ollama модели: `nomic-embed-text` и `llama3`
- Пакеты из requirements.txt
Запуск:
```bash
python main.py
```
В интерактивном режиме можно задавать вопросы. В примере уже есть три готовых вопроса – два из Chroma, один из MCP‑тул.
"""
import json
import os
import asyncio
import sys
from pathlib import Path
from langchain_openai import ChatOpenAI, OpenAIEmbeddings
from typing import List
import httpx
from langchain_ollama import ChatOllama, OllamaEmbeddings
from langchain_chroma import Chroma
from langchain_core.documents import Document
from langchain.tools import tool
from deepagents import create_deep_agent
from deepagents.backends import FilesystemBackend, LocalShellBackend, CompositeBackend
from langchain_core.messages import HumanMessage
from langchain_core.tools import BaseTool, tool
from langchain_core.prompts import ChatPromptTemplate
from langchain_core.output_parsers import StrOutputParser
from langchain_core.runnables import Runnable
from langchain.agents import create_agent, AgentExecutor, Tool
# --------------------- Configuration ---------------------
BASE_DIR = Path(__file__).parent
DATA_DIR = BASE_DIR / "data"
CHROMA_DIR = BASE_DIR / "chroma_faq"
MOCK_META_FILE = BASE_DIR / "course_meta.json"
# ---------------------------------------------------------------------------
# 1. Векторная база
# ---------------------------------------------------------------------------
CHROMA_PATH = Path("./chroma_faq")
DATA_PATH = Path("./data")
# --------------------- LLM and Embeddings ---------------------
llm = ChatOpenAI(
model="openai/gpt-oss-20b:free",
base_url="https://openrouter.ai/api/v1",
api_key=os.getenv("OPENAI_API_KEY"),
temperature=0.0,
)
# Создаём embeddings
embeddings = OllamaEmbeddings(model="nomic-embed-text")
embeddings = OpenAIEmbeddings(
model="text-embedding-3-small",
base_url="https://openrouter.ai/api/v1",
api_key=os.getenv("OPENAI_API_KEY"),
)
# ---------------------------------------------------------------------------
# Чтение markdown‑файлов и загрузка в Chroma
# ---------------------------------------------------------------------------
# --------------------- Chroma Vector Store ---------------------
vector_store = Chroma(
collection_name="faq_collection",
embedding_function=embeddings,
persist_directory=str(CHROMA_DIR),
)
def load_faq_to_chroma() -> Chroma:
"""Загружает все .md файлы из DATA_PATH в Chroma.
Если коллекция уже существует – просто возвращаем её.
"""
if CHROMA_PATH.exists():
return Chroma(
collection_name="faq",
embedding_function=embeddings,
persist_directory=str(CHROMA_PATH),
)
# Если нет, создаём новую коллекцию
from langchain_text_splitters import MarkdownTextSplitter
# --------------------- Tools ---------------------
splitter = MarkdownTextSplitter(chunk_size=500, chunk_overlap=50)
docs = []
for md_file in DATA_PATH.glob("*.md"):
text = md_file.read_text(encoding="utf-8")
docs.extend(splitter.split_text(text))
vector_store = Chroma.from_texts(
texts=docs,
embedding=embeddings,
collection_name="faq",
persist_directory=str(CHROMA_PATH),
)
return vector_store
# ---------------------------------------------------------------------------
# 2. Tool: поиск по Chroma
# ---------------------------------------------------------------------------
@tool
def search_course_docs(query: str, k: int = 3) -> str:
"""Search the local FAQ collection for relevant passages."""
docs = vector_store.similarity_search(query, k=k)
if not docs:
return "No relevant information found in the course materials."
return "\n\n---\n\n".join(f"**{doc.metadata.get('title', 'Document')}**\n{doc.page_content}" for doc in docs)
"""Возвращает кортеж из k наиболее релевантных фрагментов.
Формат ответа: ``source: chroma`` + текст.
"""
vector_store = load_faq_to_chroma()
results = vector_store.similarity_search(query, k=k)
snippets = "\n---\n".join([r.page_content for r in results])
return f"source: chroma\n{snippets}"
# ---------------------------------------------------------------------------
# 3. MCP‑подобный инструмент – HTTP‑запрос к статическому JSON
# ---------------------------------------------------------------------------
MCP_JSON_PATH = Path("./course_meta.json")
@tool
def fetch_course_meta(query: str) -> str:
"""Mock MCP-style tool that returns course metadata.
In production this would be an HTTP call to an MCP server.
Here we read a local JSON file for simplicity.
"""Имитирует вызов MCP‑сервера. Читает локальный JSON и возвращает
информацию, содержащуюся в ключе, совпадающем с query.
"""
import json
if not MOCK_META_FILE.exists():
return "Metadata source not available."
with open(MOCK_META_FILE, "r", encoding="utf-8") as f:
data = json.load(f)
# Simple keyword search in the metadata
results = [f"{k}: {v}" for k, v in data.items() if query.lower() in k.lower() or query.lower() in str(v).lower()]
return "\n".join(results) if results else "No metadata matches your query."
if not MCP_JSON_PATH.exists():
return "source: mcp_meta\nMeta file not found."
data = json.loads(MCP_JSON_PATH.read_text(encoding="utf-8"))
# простая логика: ищем ключ, содержащий query (caseinsensitive)
for key, value in data.items():
if query.lower() in key.lower():
return f"source: mcp_meta\n{key}: {value}"
return "source: mcp_meta\nNo matching metadata found."
# --------------------- Backend ---------------------
backend = CompositeBackend([
LocalShellBackend(workspace_dir="./workspace"),
FilesystemBackend(),
])
# --------------------- Agent ---------------------
agent = create_deep_agent(
model=llm,
tools=[search_course_docs, fetch_course_meta],
backend=backend,
system_prompt=(
"You are a helpful FAQ bot for the course.\n"
"Use the search_course_docs tool for questions about lecture materials.\n"
"Use the fetch_course_meta tool for questions about schedule or metadata.\n"
"Do not call both tools unless absolutely necessary.\n"
"In your final answer, prefix the source with 'source: chroma' or 'source: mcp_meta'."
),
# ---------------------------------------------------------------------------
# 4. Создание агента
# ---------------------------------------------------------------------------
# Системный промпт, который заставляет агент выбирать нужный инструмент
SYSTEM_PROMPT = (
"You are a helpful assistant for a course FAQ. Use the provided tools to answer the user. "
"If the question is about course materials, use search_course_docs. "
"If it is about schedule or metadata, use fetch_course_meta. "
"Do not use both tools unless necessary. "
"Always prefix your answer with the source: chroma or source: mcp_meta."
)
# --------------------- Data Loading ---------------------
async def load_faq_to_chroma():
"""Load all .md files from data/ into the Chroma collection."""
if not DATA_DIR.exists():
print("Data directory not found.")
return
docs = []
for md_file in DATA_DIR.glob("*.md"):
text = md_file.read_text(encoding="utf-8")
docs.append(Document(page_content=text, metadata={"title": md_file.stem}))
if docs:
vector_store.add_documents(docs)
vector_store.persist()
print(f"Loaded {len(docs)} documents into Chroma.")
else:
print("No markdown files found in data/.")
# Создаём LLM
llm = ChatOllama(model="llama3", temperature=0.2)
# --------------------- CLI ---------------------
PRESET_QUESTIONS = [
"What is the deadline for the final project?", # chroma
"Explain the concept of tokenization in NLP.", # chroma
"When is the next lecture scheduled?", # mcp_meta
# Prompt template
prompt = ChatPromptTemplate.from_messages([
("system", SYSTEM_PROMPT),
("human", "{input}"),
])
# Создаём Runnable, который будет использовать инструменты
agent = create_agent(
llm=llm,
tools=[search_course_docs, fetch_course_meta],
system_message=SYSTEM_PROMPT,
verbose=True,
)
# ---------------------------------------------------------------------------
# 5. CLI
# ---------------------------------------------------------------------------
PREDEFINED_QUESTIONS = [
"What topics are covered in the first lecture?", # Chroma
"Explain the concept of polymorphism in the context of the course.", # Chroma
"What is the schedule for the next week?", # MCP
]
async def run_cli():
await load_faq_to_chroma()
print("\n--- FAQ Bot CLI ---\n")
for i, q in enumerate(PRESET_QUESTIONS, 1):
def run_cli():
print("--- FAQ Bot ---")
print("Predefined questions:")
for i, q in enumerate(PREDEFINED_QUESTIONS, 1):
print(f"{i}. {q}")
print("\nEnter your own question (or 'exit' to quit):")
print("\nEnter 1-3 to ask a predefined question, or type your own question.")
while True:
user_input = input("> ")
user_input = input("\n> ")
if user_input.lower() in {"exit", "quit"}:
print("Goodbye!")
break
result = await agent.ainvoke(
{"messages": [HumanMessage(content=user_input)]},
{"configurable": {"thread_id": "session-1"}},
)
print(result["messages"][-1].content)
if user_input.isdigit() and 1 <= int(user_input) <= len(PREDEFINED_QUESTIONS):
question = PREDEFINED_QUESTIONS[int(user_input) - 1]
else:
question = user_input
try:
response = agent.invoke({"input": question})
print("\nAnswer:\n", response)
except Exception as e:
print("Error:", e)
if __name__ == "__main__":
asyncio.run(run_cli())
# Убедимся, что данные загружены
load_faq_to_chroma()
run_cli()