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Python

"""API REST de prediction de consommation electrique (FastAPI).
Le service orchestre la chaine de prediction :
1. recevoir la requete (client_id, date) ;
2. recuperer les features du client (feature store simule) ;
3. charger le modele promu (Model Registry, au demarrage) ;
4. calculer la prediction et repondre en JSON.
Lancement : uvicorn lab.serving.api:app --host 0.0.0.0 --port 8000
Swagger UI : /docs
"""
import logging
from contextlib import asynccontextmanager
from fastapi import FastAPI, HTTPException
from . import features, registry
from .schemas import (
BatchPredictionRequest,
BatchPredictionResponse,
PredictionRequest,
PredictionResponse,
)
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)
# Modele charge une fois au demarrage (couteux) et reutilise a chaque requete.
_state: dict[str, registry.LoadedModel] = {}
@asynccontextmanager
async def lifespan(app: FastAPI):
_state["model"] = registry.load_champion()
yield
_state.clear()
app = FastAPI(
title="Electricity Consumption Prediction API",
description="Expose le modele promu (MLflow Model Registry) via une API REST.",
version="1.0.0",
lifespan=lifespan,
)
def _get_model() -> registry.LoadedModel:
model = _state.get("model")
if model is None: # modele indisponible au demarrage
raise HTTPException(status_code=503, detail="Modele non charge.")
return model
def _predict(client_id: str, model: registry.LoadedModel) -> PredictionResponse:
feats = features.get_features(client_id) # peut lever UnknownClientError
prediction = model.predict_one(feats)
return PredictionResponse(
client_id=client_id,
prediction_kwh=prediction,
model_name=model.name,
model_version=model.version,
)
@app.get("/health", summary="Verification de l'etat du service")
def health() -> dict[str, str]:
"""Endpoint de sante : renvoie 200 si le service repond."""
return {"status": "ok"}
@app.post("/predict", response_model=PredictionResponse, summary="Prediction unitaire")
def predict(request: PredictionRequest) -> PredictionResponse:
model = _get_model()
try:
return _predict(request.client_id, model)
except features.UnknownClientError:
# Partie 3 : client inconnu -> erreur cliente, pas un plantage du service.
raise HTTPException(
status_code=404,
detail=f"Client inconnu : aucune feature pour '{request.client_id}'.",
)
@app.post(
"/predict/batch",
response_model=BatchPredictionResponse,
summary="Prediction en batch (plusieurs clients)",
)
def predict_batch(request: BatchPredictionRequest) -> BatchPredictionResponse:
model = _get_model()
predictions: list[PredictionResponse] = []
unknown: list[str] = []
for client_id in request.client_ids:
try:
predictions.append(_predict(client_id, model))
except features.UnknownClientError:
unknown.append(client_id)
return BatchPredictionResponse(predictions=predictions, unknown_client_ids=unknown)