Files

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5.8 KiB
Python

"""Estrategias de extracción de información desde imágenes de documentos.
Define la interfaz `InvoiceExtractorStrategy` y una implementación basada en
un endpoint compatible con la API de OpenAI para modelos multimodales.
"""
from __future__ import annotations
from abc import ABC, abstractmethod
from typing import List, Dict, Any, Optional
from .config import extractor_llm_config
from .llm_client import LLMClient
import logging
import time
class InvoiceExtractorStrategy(ABC):
"""Interfaz para extraer datos a partir de páginas en base64 e instrucción."""
@abstractmethod
def extract(self, images_b64: List[str], instruction: str, history: Optional[List[Dict[str, Any]]] = None) -> Dict[str, Any]:
"""Devuelve un dict con al menos la clave "raw" (texto de salida del modelo)."""
raise NotImplementedError
async def extract_async(self, images_b64: List[str], instruction: str, history: Optional[List[Dict[str, Any]]] = None) -> Dict[str, Any]:
"""Versión asíncrona de extract. Por defecto lanza NotImplementedError."""
raise NotImplementedError
_LOG_EXTRA_BASE = {"dpi": '-', "pdf": '-', "radicado": '-'}
class OpenAICompatibleExtractor(InvoiceExtractorStrategy):
"""Extractor contra un backend compatible con Chat Completions.
Parámetros configurables: `api_key`, `base_url` y `model`.
"""
def __init__(self, api_key: Optional[str] = None, base_url: Optional[str] = None, model: Optional[str] = None, llm_client: Optional[LLMClient] = None) -> None:
config = extractor_llm_config()
self.api_key = api_key if api_key is not None else str(config["api_key"])
self.base_url = base_url if base_url is not None else str(config["base_url"])
self.model = model if model is not None else str(config["model"])
self.request_timeout_s = float(config["timeout_s"])
self.llm = llm_client or LLMClient(
api_key=self.api_key,
base_url=self.base_url,
default_model=self.model,
request_timeout_s=self.request_timeout_s,
)
self._logger = logging.getLogger(__name__)
def _build_messages(self, images_b64: List[str], instruction: str, history: Optional[List[Dict[str, Any]]]) -> List[Dict[str, Any]]:
content: List[Dict[str, Any]] = [
{"type": "image_url", "image_url": {"url": f"data:image/png;base64,{img}"}}
for img in images_b64
]
content.append({"type": "text", "text": instruction})
messages = list(history) if history else []
messages.append({"role": "user", "content": content})
return messages
def _log_call_start(self, images_b64: List[str], instruction: str, history: Optional[List[Dict[str, Any]]]) -> None:
prompt_len = len(instruction) if isinstance(instruction, str) else 0
self._logger.info(
"backend_call_start",
extra={**_LOG_EXTRA_BASE, "base_url": self.base_url, "model": self.model,
"timeout_s": self.request_timeout_s, "images": len(images_b64),
"prompt_len": prompt_len, "history_len": len(history) if history else 0},
)
self._logger.debug(
f"Llamada backend: images={len(images_b64)}, prompt_len={prompt_len}, history_len={len(history) if history else 0}",
extra=_LOG_EXTRA_BASE,
)
def _log_call_ok(self, elapsed: float) -> None:
self._logger.info(
"Extracción completada",
extra={**_LOG_EXTRA_BASE, "base_url": self.base_url, "model": self.model,
"timeout_s": self.request_timeout_s, "elapsed_ms": int(elapsed * 1000)},
)
self._logger.debug(f"Backend OK (elapsed_ms={int(elapsed*1000)})", extra=_LOG_EXTRA_BASE)
def _log_call_error(self, elapsed: float) -> None:
self._logger.exception(
"Error en llamada al backend",
extra={**_LOG_EXTRA_BASE, "base_url": self.base_url, "model": self.model,
"timeout_s": self.request_timeout_s, "elapsed_ms": int(elapsed * 1000)},
)
self._logger.debug(f"Backend error tras {int(elapsed*1000)} ms", extra=_LOG_EXTRA_BASE)
def extract(self, images_b64: List[str], instruction: str, history: Optional[List[Dict[str, Any]]] = None) -> Dict[str, Any]:
"""Construye el prompt multimodal y devuelve el texto crudo del modelo."""
messages = self._build_messages(images_b64, instruction, history)
self._log_call_start(images_b64, instruction, history)
start = time.time()
try:
text, usage_dict = self.llm.chat_text(
messages=messages, model=self.model,
timeout_s=self.request_timeout_s, component="extractor",
)
self._log_call_ok(time.time() - start)
return {"raw": text, "usage": usage_dict}
except Exception:
self._log_call_error(time.time() - start)
raise
async def extract_async(self, images_b64: List[str], instruction: str, history: Optional[List[Dict[str, Any]]] = None) -> Dict[str, Any]:
"""Versión asíncrona de extract."""
messages = self._build_messages(images_b64, instruction, history)
self._log_call_start(images_b64, instruction, history)
start = time.time()
try:
text, usage_dict = await self.llm.chat_text_async(
messages=messages, model=self.model,
timeout_s=self.request_timeout_s, component="extractor",
)
self._log_call_ok(time.time() - start)
return {"raw": text, "usage": usage_dict}
except Exception:
self._log_call_error(time.time() - start)
raise
def update_config(self, *, api_key: str | None = None, base_url: str | None = None, model: str | None = None) -> None:
"""Actualiza la configuración del cliente y recrea la instancia interna."""
if api_key is not None:
self.api_key = api_key
if base_url is not None:
self.base_url = base_url
if model is not None:
self.model = model
# actualizar cliente LLM con config actual
self.llm.update_config(api_key=self.api_key, base_url=self.base_url, default_model=self.model, request_timeout_s=self.request_timeout_s)