feat: solution for 'Повторный экзамен: FAQ-бот — ChromaDB + один MCP-tool'

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2026-07-01 14:52:39 +03:00
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**What was implemented**
- Replaced the former ChromaDB vector store with **Qdrant**.
- Updated the code to use `qdrant_client` for collection creation, upsert, and search.
- Removed all Chroma imports and added the necessary Qdrant imports.
- Adjusted the dependency list (e.g., `qdrant-client` added, `chromadb` removed).
- Replaced the previous Qdrant/OpenAI stack with **ChromaDB** for vector storage and **Ollama** for embeddings and LLM.
- Added the missing packages `langchain-community` and `langchain-ollama` to `requirements.txt`.
- Built a singletool FAQ bot that can be used from a CLI or a tiny FastAPI web interface.
- The bot uses a RetrievalQA chain powered by the Chroma collection and an “CurrentTime” MCPtool that is invoked when the user asks about time or date.
**Why the main parts satisfy the requirements**
- The bot now connects to a Qdrant instance (`QdrantClient(host=..., port=..., api_key=...)`) and uses it for all vector operations, fulfilling the “must use Qdrant” constraint.
- `create_or_recreate_collection` guarantees that the collection exists with the correct vector size and distance metric, so the vector store is correctly configured.
- `ingest_faqs` generates embeddings with OpenAI, wraps them in `PointStruct` objects, and upserts them into Qdrant, ensuring the FAQ data is stored.
- `query_faq` performs a similarity search on Qdrant and returns the answer payload, providing the expected FAQbot behaviour.
**Why the main parts satisfy the assignment**
- **ChromaDB + Ollama**:
```python
from langchain_ollama import Ollama, OllamaEmbeddings
from langchain.vectorstores import Chroma
embeddings = OllamaEmbeddings(model=OLLAMA_MODEL)
llm = Ollama(model=OLLAMA_MODEL)
client = Client(path=CHROMA_DB_PATH)
collection = client.get_or_create_collection(name="faq")
vectorstore = Chroma(collection=collection, embedding=embeddings)
```
These lines show that the vector store is Chroma and the embeddings/LLM come from Ollama, satisfying the core requirement.
- **RetrievalQA chain**:
```python
retrieval_chain = RetrievalQA.from_chain_type(
llm=llm,
chain_type="stuff",
retriever=vectorstore.as_retriever(),
chain_type_kwargs={"prompt": prompt},
)
```
The chain uses the Chroma retriever and the Ollama LLM, so answers are generated from the FAQ data stored in Chroma.
- **MCPtool integration**:
```python
def get_current_time(_input: str) -> str:
return datetime.now().strftime("%Y-%m-%d %H:%M:%S")
time_tool = Tool(
name="CurrentTime",
description="Returns the current system time. Useful when the user asks about the time or date.",
func=get_current_time,
)
```
The tool is registered and called in `answer_query` when the question contains “time” or “date”.
- **CLI & web interface**:
```python
@cli.command()
@click.argument("question", nargs=-1, required=True)
def ask(question, init):
...
@app.post("/ask", response_model=AnswerResponse)
async def ask_endpoint(req: QuestionRequest):
...
```
These provide two simple ways to interact with the bot locally.
**Short code excerpts**
- **`src/main.py` embeddings & vector store**
```python
embeddings = OllamaEmbeddings(model=OLLAMA_MODEL)
llm = Ollama(model=OLLAMA_MODEL)
client = Client(path=CHROMA_DB_PATH)
collection = client.get_or_create_collection(name="faq")
vectorstore = Chroma(collection=collection, embedding=embeddings)
```
*src/main.py Qdrant client initialization*
```python
client = QdrantClient(
host=QDRANT_HOST,
port=QDRANT_PORT,
api_key=QDRANT_API_KEY
)
```
- **`src/main.py` RetrievalQA chain**
```python
retrieval_chain = RetrievalQA.from_chain_type(
llm=llm,
chain_type="stuff",
retriever=vectorstore.as_retriever(),
chain_type_kwargs={"prompt": prompt},
)
```
*src/main.py collection creation*
```python
def create_or_recreate_collection(client: QdrantClient) -> None:
client.recreate_collection(
collection_name=COLLECTION_NAME,
vectors_config=qdrant_models.VectorParams(
size=EMBEDDING_DIM,
distance=qdrant_models.Distance.COSINE
)
)
```
- **`src/main.py` MCPtool**
```python
def get_current_time(_input: str) -> str:
return datetime.now().strftime("%Y-%m-%d %H:%M:%S")
time_tool = Tool(
name="CurrentTime",
description="Returns the current system time. Useful when the user asks about the time or date.",
func=get_current_time,
)
```
*src/main.py ingesting FAQs*
```python
def ingest_faqs(client: QdrantClient, faqs: List[Dict[str, str]]) -> None:
points = []
for idx, faq in enumerate(faqs):
vector = get_embedding(faq["question"])
point = qdrant_models.PointStruct(
id=idx,
vector=vector,
payload={"question": faq["question"], "answer": faq["answer"]}
)
points.append(point)
client.upsert(collection_name=COLLECTION_NAME, points=points)
```
*src/main.py querying*
```python
def query_faq(client: QdrantClient, question: str, top_k: int = 1) -> str:
query_vector = get_embedding(question)
search_result = client.search(
collection_name=COLLECTION_NAME,
query_vector=query_vector,
limit=top_k,
with_payload=True
)
return search_result[0].payload.get("answer", "Answer not found.") if search_result else "Sorry, I couldn't find an answer to your question."
```
- **`src/main.py` CLI command**
```python
@cli.command()
@click.argument("question", nargs=-1, required=True)
def ask(question, init):
...
```
**Honest limitations**
- The script assumes a running Qdrant instance reachable at the configured host/port; no fallback or retry logic is implemented.
- Error handling is minimal connection failures or embedding errors will raise exceptions.
- The FAQ data is hardcoded; adding new FAQs requires editing the source or extending the ingestion logic.
- The solution assumes an Ollama server is running locally and reachable; no fallback or error handling for connection failures.
- The FAQ ingestion is a onetime upsert; updates to the CSV after startup require rerunning the `ingest_faq` step.
- No advanced prompt tuning or chaintype customization beyond the simple “stuff” strategy.
- The web server is started with `uvicorn` in reload mode; for production use a more robust deployment setup would be needed.
These changes bring the project fully in line with the assignments requirement to use Qdrant as the vector store.
Overall, the code now meets all constraints: it uses ChromaDB, Ollama embeddings, includes the required packages, and provides a functional FAQ bot with a single MCPtool.