#!/usr/bin python3 """ Settings manager for Keras Backend """ from __future__ import annotations from contextlib import nullcontext import logging import typing as T import numpy as np import tensorflow as tf # Ignore linting errors from Tensorflow's thoroughly broken import system from tensorflow.keras.layers import Activation # pylint:disable=import-error from tensorflow.keras.models import load_model as k_load_model, Model # noqa:E501 # pylint:disable=import-error from lib.utils import get_backend if T.TYPE_CHECKING: from collections.abc import Callable logger = logging.getLogger(__name__) class KSession(): """ Handles the settings of backend sessions for inference models. This class acts as a wrapper for various :class:`keras.Model()` functions, ensuring that actions performed on a model are handled consistently and can be performed in parallel in separate threads. This is an early implementation of this class, and should be expanded out over time. Notes ----- The documentation refers to :mod:`keras`. This is a pseudonym for either :mod:`keras` or :mod:`tensorflow.keras` depending on the backend in use. Parameters ---------- name: str The name of the model that is to be loaded model_path: str The path to the keras model file model_kwargs: dict, optional Any kwargs that need to be passed to :func:`keras.models.load_models()`. Default: ``None`` allow_growth: bool, optional Enable the Tensorflow GPU allow_growth configuration option. This option prevents Tensorflow from allocating all of the GPU VRAM, but can lead to higher fragmentation and slower performance. Default: ``False`` exclude_gpus: list, optional A list of indices correlating to connected GPUs that Tensorflow should not use. Pass ``None`` to not exclude any GPUs. Default: ``None`` cpu_mode: bool, optional ``True`` run the model on CPU. Default: ``False`` """ def __init__(self, name: str, model_path: str, model_kwargs: dict | None = None, allow_growth: bool = False, exclude_gpus: list[int] | None = None, cpu_mode: bool = False) -> None: logger.trace("Initializing: %s (name: %s, model_path: %s, " # type:ignore "model_kwargs: %s, allow_growth: %s, exclude_gpus: %s, cpu_mode: %s)", self.__class__.__name__, name, model_path, model_kwargs, allow_growth, exclude_gpus, cpu_mode) self._name = name self._backend = get_backend() self._context = self._set_session(allow_growth, [] if exclude_gpus is None else exclude_gpus, cpu_mode) self._model_path = model_path self._model_kwargs = {} if not model_kwargs else model_kwargs self._model: Model | None = None logger.trace("Initialized: %s", self.__class__.__name__,) # type:ignore def predict(self, feed: list[np.ndarray] | np.ndarray, batch_size: int | None = None) -> list[np.ndarray] | np.ndarray: """ Get predictions from the model. This method is a wrapper for :func:`keras.predict()` function. For Tensorflow backends this is a straight call to the predict function. Parameters ---------- feed: numpy.ndarray or list The feed to be provided to the model as input. This should be a :class:`numpy.ndarray` for single inputs or a `list` of :class:`numpy.ndarray` objects for multiple inputs. batchsize: int, optional The batch size to run prediction at. Default ``None`` Returns ------- :class:`numpy.ndarray` The predictions from the model """ assert self._model is not None with self._context: return self._model.predict(feed, verbose=0, batch_size=batch_size) def _set_session(self, allow_growth: bool, exclude_gpus: list, cpu_mode: bool) -> T.ContextManager: """ Sets the backend session options. For CPU backends, this hides any GPUs from Tensorflow. For Nvidia backends, this hides any GPUs that Tensorflow should not use and applies any allow growth settings Parameters ---------- allow_growth: bool Enable the Tensorflow GPU allow_growth configuration option. This option prevents Tensorflow from allocating all of the GPU VRAM, but can lead to higher fragmentation and slower performance exclude_gpus: list A list of indices correlating to connected GPUs that Tensorflow should not use. Pass ``None`` to not exclude any GPUs cpu_mode: bool ``True`` run the model on CPU. Default: ``False`` """ retval = nullcontext() if self._backend == "cpu": logger.verbose("Hiding GPUs from Tensorflow") # type:ignore tf.config.set_visible_devices([], "GPU") return retval gpus = tf.config.list_physical_devices('GPU') if exclude_gpus: gpus = [gpu for idx, gpu in enumerate(gpus) if idx not in exclude_gpus] logger.debug("Filtering devices to: %s", gpus) tf.config.set_visible_devices(gpus, "GPU") if allow_growth and self._backend == "nvidia": for gpu in gpus: logger.info("Setting allow growth for GPU: %s", gpu) tf.config.experimental.set_memory_growth(gpu, True) if cpu_mode: retval = tf.device("/device:cpu:0") return retval def load_model(self) -> None: """ Loads a model. This method is a wrapper for :func:`keras.models.load_model()`. Loads a model and its weights from :attr:`model_path` defined during initialization of this class. Any additional ``kwargs`` to be passed to :func:`keras.models.load_model()` should also be defined during initialization of the class. For Tensorflow backends, the `make_predict_function` method is called on the model to make it thread safe. """ logger.verbose("Initializing plugin model: %s", self._name) # type:ignore with self._context: self._model = k_load_model(self._model_path, compile=False, **self._model_kwargs) self._model.make_predict_function() def define_model(self, function: Callable) -> None: """ Defines a model from the given function. This method acts as a wrapper for :class:`keras.models.Model()`. Parameters ---------- function: function A function that defines a :class:`keras.Model` and returns it's ``inputs`` and ``outputs``. The function that generates these results should be passed in, NOT the results themselves, as the function needs to be executed within the correct context. """ with self._context: self._model = Model(*function()) def load_model_weights(self) -> None: """ Load model weights for a defined model inside the correct session. This method is a wrapper for :class:`keras.load_weights()`. Once a model has been defined in :func:`define_model()` this method can be called to load its weights from the :attr:`model_path` defined during initialization of this class. For Tensorflow backends, the `make_predict_function` method is called on the model to make it thread safe. """ logger.verbose("Initializing plugin model: %s", self._name) # type:ignore assert self._model is not None with self._context: self._model.load_weights(self._model_path) self._model.make_predict_function() def append_softmax_activation(self, layer_index: int = -1) -> None: """ Append a softmax activation layer to a model Occasionally a softmax activation layer needs to be added to a model's output. This is a convenience function to append this layer to the loaded model. Parameters ---------- layer_index: int, optional The layer index of the model to select the output from to use as an input to the softmax activation layer. Default: `-1` (The final layer of the model) """ logger.debug("Appending Softmax Activation to model: (layer_index: %s)", layer_index) assert self._model is not None with self._context: softmax = Activation("softmax", name="softmax")(self._model.layers[layer_index].output) self._model = Model(inputs=self._model.input, outputs=[softmax])