legco_ai_assistant/backend/app/services/rag.py

343 lines
12 KiB
Python

"""RAG service for embedding, retrieval, and response generation."""
import uuid
from typing import TYPE_CHECKING, List, Tuple, Dict, Any, Optional
import logging
from app.core.config import Settings
from app.core.database import get_chroma_client
if TYPE_CHECKING:
from app.services.prompt_service import PromptService
logger = logging.getLogger(__name__)
class RAGService:
"""Service for document ingestion, retrieval, and response generation."""
def __init__(
self,
chroma_client=None,
llm_client=None,
settings: Optional[Settings] = None,
prompt_service: "PromptService | None" = None,
):
self.chroma_client = chroma_client or get_chroma_client()
self.llm_client = llm_client
self.settings = settings
self._prompt_service = prompt_service
self._collection = None
@property
def collection(self):
if self._collection is None:
from app.core.database import get_or_create_collection, get_embedding_function_settings
embedding_fn = None
if self.settings is not None:
embedding_fn = get_embedding_function_settings(self.settings)
self._collection = get_or_create_collection(
self.chroma_client, "documents", embedding_function=embedding_fn
)
return self._collection
def ingest_document(
self,
file_path: str,
chunks: List[str],
metadata_list: List[Dict[str, Any]],
document_id: Optional[str] = None,
) -> str:
if not chunks:
return ""
document_id = document_id or str(uuid.uuid4())
ids = [f"{document_id}_{i}" for i in range(len(chunks))]
self.collection.add(
documents=chunks,
metadatas=metadata_list,
ids=ids,
)
return document_id
def retrieve_per_subquestion(
self,
sub_questions: List[str],
n_results: int = 10,
) -> List[Tuple[str, List[Tuple[str, Dict[str, Any], float]]]]:
"""Retrieve chunks for each sub-question independently.
Calls retrieve() once per sub-question to get chunks specifically
relevant to each decomposed question, rather than joining all
sub-questions into a single query string.
Args:
sub_questions: List of decomposed sub-questions from QueryDecomposer.
n_results: Number of chunks to retrieve per sub-question.
Returns:
List of (sub_question, chunks) tuples. Each chunks list contains
(text, metadata, distance) tuples in the standard retrieve() format.
Returns empty list if sub_questions is empty.
"""
if not sub_questions:
return []
results: List[Tuple[str, List[Tuple[str, Dict[str, Any], float]]]] = []
for sub_q in sub_questions:
chunks = self.retrieve([sub_q], n_results=n_results)
results.append((sub_q, chunks))
return results
def retrieve(
self,
query_keywords: List[str],
n_results: int = 10,
) -> List[Tuple[str, Dict[str, Any], float]]:
query_text = " ".join(query_keywords)
results = self.collection.query(
query_texts=[query_text],
n_results=n_results,
)
chunks = []
if results["documents"] and results["documents"][0]:
for i, doc in enumerate(results["documents"][0]):
metadata = results["metadatas"][0][i] if results["metadatas"][0] else {}
distance = results["distances"][0][i] if results["distances"][0] else 0.0
chunks.append((doc, metadata, distance))
return chunks
async def generate_response(
self,
question: str,
chunks: List[str],
metadata_list: List[Dict[str, Any]],
) -> Tuple[str, str]:
"""Generate a RAG response and return it alongside the prompt used.
Args:
question: The user's question.
chunks: Retrieved chunk texts.
metadata_list: Metadata dicts corresponding to each chunk.
Returns:
A tuple of (answer, prompt). answer is the LLM-generated response
(or a fallback message). prompt is the rendered prompt string, or
``""`` when no prompt was built.
"""
if not chunks:
return "I could not find any relevant information to answer your question.", ""
if self.llm_client is None:
return "LLM client not configured.", ""
context_parts = []
for i, (chunk, meta) in enumerate(zip(chunks, metadata_list)):
source = meta.get("filename", "unknown")
summary = meta.get("content_summary", "")
page_num = meta.get("page_number")
citation_label = f"{source}, page {page_num}" if page_num else source
context_parts.append(
f"[{citation_label}] Source: {source}\n"
f"Summary: {summary}\n"
f"Content: {chunk}\n"
)
context = "\n".join(context_parts)
if self._prompt_service is not None:
template = self._prompt_service.get_prompt_template("generate")
else:
template = (
f"Question: {'{question}'}\n\n"
f"Answer the question using ONLY these document chunks. "
f"Do not use any external knowledge. "
f"Format your answer as bullet points. "
f"Cite your sources inline using the exact bracket labels provided, "
f"e.g. [filename, page N]. Place the citation at the end of each relevant point.\n\n"
f"Document chunks:\n{'{context}'}\n\n"
f"Answer:"
)
# str.replace is safe even with stray curly braces in user text.
prompt = template.replace("{question}", question).replace("{context}", context)
result = await self.llm_client.complete(prompt=prompt, temperature=0.3, step_name="ResponseGeneration")
return result, prompt
async def generate_response_per_subquestion(
self,
sub_questions: List[str],
sub_chunks: List[List[str]],
sub_metadata: List[List[Dict[str, Any]]],
) -> Tuple[str, str, List[List[Dict[str, Any]]]]:
"""Generate sub-question-organized RAG response.
Builds context sections for each sub-question and asks the LLM to
answer each one using only its own document chunks. Returns the
full markdown answer plus sources organized by sub-question.
Args:
sub_questions: List of decomposed sub-questions.
sub_chunks: List of chunk text lists (one per sub-question).
sub_metadata: List of metadata dict lists (one per sub-question).
Must be same length as sub_chunks, with inner lists matching.
Returns:
Tuple of (answer, prompt, grouped_sources).
answer: Markdown string with ## Sub-question N: sections.
prompt: The rendered LLM prompt string.
grouped_sources: List of metadata dict lists (one per sub-question),
each metadata dict is a SourceMetadata-compatible dict.
"""
if not sub_questions:
return (
"I could not find any relevant information to answer your question.",
"",
[],
)
has_chunks = any(len(c) > 0 for c in sub_chunks)
if not has_chunks:
return (
"I could not find any relevant information to answer your question.",
"",
[],
)
if self.llm_client is None:
return ("LLM client not configured.", "", [])
context_parts = []
for idx, (sq, chunks, metas) in enumerate(
zip(sub_questions, sub_chunks, sub_metadata)
):
context_parts.append(
f'### Context for Sub-question {idx}: "{sq}"'
)
for chunk, meta in zip(chunks, metas):
source = meta.get("filename", "unknown")
summary = meta.get("content_summary", "")
page_num = meta.get("page_number")
citation_label = (
f"{source}, page {page_num}" if page_num else source
)
context_parts.append(
f"[{citation_label}] Source: {source}\n"
f"Summary: {summary}\n"
f"Content: {chunk}\n"
)
context_sections = "\n".join(context_parts)
if self._prompt_service is not None:
template = self._prompt_service.get_prompt_template(
"generate_per_subq"
)
else:
template = (
"You must answer each sub-question using ONLY the document "
"chunks provided for it.\n"
"Do not use any external knowledge.\n"
"Format your answer as markdown sections — one section per "
"sub-question.\n"
'Each section should start with "## Sub-question N: '
'<the question>"\n'
"Each section should contain 1-5 bullet points.\n"
"Cite your sources inline using bracket labels, "
"e.g. [filename, page N].\n"
"Place the citation at the end of each relevant bullet point."
"\n\n"
"{context_sections}\n\n"
"Answer:"
)
prompt = template.replace("{context_sections}", context_sections)
answer = await self.llm_client.complete(
prompt=prompt, temperature=0.3, step_name="ResponseGeneration"
)
grouped_sources: List[List[Dict[str, Any]]] = []
for metas in sub_metadata:
grouped_sources.append(list(metas))
return answer, prompt, grouped_sources
def list_documents(self) -> Tuple[List[Dict[str, Any]], int, int]:
from collections import defaultdict
all_data = self.collection.get(include=["metadatas"])
if not all_data["metadatas"]:
return [], 0, 0
docs = defaultdict(lambda: {"filename": "", "chunk_count": 0, "upload_date": ""})
for chunk_id, meta in zip(all_data["ids"], all_data["metadatas"]):
parts = chunk_id.rsplit("_", 1)
doc_id = parts[0] if len(parts) == 2 else chunk_id
docs[doc_id]["filename"] = meta.get("filename", "unknown")
docs[doc_id]["chunk_count"] += 1
docs[doc_id]["upload_date"] = meta.get("upload_date", "")
total_chunks = sum(d["chunk_count"] for d in docs.values())
doc_list = [
{
"document_id": doc_id,
"filename": info["filename"],
"chunk_count": info["chunk_count"],
"upload_date": info["upload_date"],
}
for doc_id, info in docs.items()
]
return doc_list, len(doc_list), total_chunks
def list_chunks(self, document_id: str) -> List[Dict[str, Any]]:
all_data = self.collection.get(include=["metadatas"])
chunks = []
for chunk_id, meta in zip(all_data["ids"], all_data["metadatas"]):
if chunk_id.startswith(f"{document_id}_"):
chunks.append({
"chunk_id": chunk_id,
"chunk_index": meta.get("chunk_index", 0),
"content_summary": meta.get("content_summary", ""),
"page_number": meta.get("page_number"),
"chunk_file_path": meta.get("chunk_file_path"),
})
chunks.sort(key=lambda x: x["chunk_index"])
return chunks
def delete_document(self, document_id: str) -> Tuple[bool, int]:
all_data = self.collection.get(include=["metadatas"])
ids_to_delete = [
chunk_id for chunk_id in all_data["ids"]
if chunk_id.startswith(f"{document_id}_")
]
if not ids_to_delete:
return False, 0
self.collection.delete(ids=ids_to_delete)
return True, len(ids_to_delete)
def delete_chunk(self, chunk_id: str) -> bool:
all_data = self.collection.get(include=["metadatas"])
if chunk_id not in all_data["ids"]:
return False
self.collection.delete(ids=[chunk_id])
return True