| from fastapi import FastAPI, HTTPException
|
| from pydantic import BaseModel
|
| from sentence_transformers import CrossEncoder
|
| from typing import List, Dict, Any, Union
|
| import uvicorn
|
| import os
|
|
|
| app = FastAPI(
|
| title="Cross-Encoder Reranking API",
|
| description="Reranking service using cross-encoder/ms-marco-MiniLM-L-6-v2",
|
| version="1.0.0"
|
| )
|
|
|
|
|
| MODEL_NAME = os.getenv("MODEL_NAME", "cross-encoder/ms-marco-MiniLM-L-6-v2")
|
| try:
|
| model = CrossEncoder(MODEL_NAME)
|
| print(f"Loaded CrossEncoder model: {MODEL_NAME}")
|
| except Exception as e:
|
| print(f"Error loading model: {e}")
|
| model = None
|
|
|
| class RerankRequest(BaseModel):
|
| query: str
|
| documents: List[str]
|
|
|
| class RerankResponse(BaseModel):
|
| scores: List[float]
|
| ranked_indices: List[int]
|
|
|
| @app.get("/")
|
| def root():
|
| return {
|
| "message": "Cross-Encoder Reranking API",
|
| "model": MODEL_NAME,
|
| "status": "active" if model else "error"
|
| }
|
|
|
| @app.get("/health")
|
| def health_check():
|
| return {"status": "healthy", "model_loaded": model is not None}
|
|
|
| @app.post("/rerank", response_model=RerankResponse)
|
| def rerank_documents(request: RerankRequest):
|
| if not model:
|
| raise HTTPException(status_code=503, detail="Model not loaded")
|
|
|
| try:
|
| if not request.documents:
|
| return RerankResponse(scores=[], ranked_indices=[])
|
|
|
|
|
| pairs = [[request.query, doc] for doc in request.documents]
|
|
|
|
|
| scores = model.predict(pairs)
|
|
|
|
|
| scores_list = scores.tolist() if hasattr(scores, 'tolist') else list(scores)
|
|
|
|
|
|
|
| indexed_scores = list(enumerate(scores_list))
|
| indexed_scores.sort(key=lambda x: x[1], reverse=True)
|
|
|
| ranked_indices = [idx for idx, score in indexed_scores]
|
|
|
| return RerankResponse(
|
| scores=scores_list,
|
| ranked_indices=ranked_indices
|
| )
|
|
|
| except Exception as e:
|
| raise HTTPException(status_code=500, detail=str(e))
|
|
|
| if __name__ == "__main__":
|
| uvicorn.run(app, host="0.0.0.0", port=7860)
|
|
|
