Source code for apache_beam.ml.inference.base

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# The ASF licenses this file to You under the Apache License, Version 2.0
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#    http://www.apache.org/licenses/LICENSE-2.0
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
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#
# TODO: https://github.com/apache/beam/issues/21822
# mypy: ignore-errors

"""An extensible run inference transform.

Users of this module can extend the ModelHandler class for any machine learning
framework. A ModelHandler implementation is a required parameter of
RunInference.

The transform handles standard inference functionality, like metric
collection, sharing model between threads, and batching elements.
"""

import logging
import os
import pickle
import sys
import threading
import time
import uuid
from collections import OrderedDict
from collections import defaultdict
from copy import deepcopy
from dataclasses import dataclass
from typing import Any
from typing import Callable
from typing import Dict
from typing import Generic
from typing import Iterable
from typing import List
from typing import Mapping
from typing import NamedTuple
from typing import Optional
from typing import Sequence
from typing import Tuple
from typing import TypeVar
from typing import Union

import apache_beam as beam
from apache_beam.utils import multi_process_shared
from apache_beam.utils import shared

try:
  # pylint: disable=wrong-import-order, wrong-import-position
  import resource
except ImportError:
  resource = None  # type: ignore[assignment]

_NANOSECOND_TO_MILLISECOND = 1_000_000
_NANOSECOND_TO_MICROSECOND = 1_000

ModelT = TypeVar('ModelT')
ExampleT = TypeVar('ExampleT')
PreProcessT = TypeVar('PreProcessT')
PredictionT = TypeVar('PredictionT')
PostProcessT = TypeVar('PostProcessT')
_INPUT_TYPE = TypeVar('_INPUT_TYPE')
_OUTPUT_TYPE = TypeVar('_OUTPUT_TYPE')
KeyT = TypeVar('KeyT')


# We use NamedTuple to define the structure of the PredictionResult,
# however, as support for generic NamedTuples is not available in Python
# versions prior to 3.11, we use the __new__ method to provide default
# values for the fields while maintaining backwards compatibility.
[docs]class PredictionResult(NamedTuple('PredictionResult', [('example', _INPUT_TYPE), ('inference', _OUTPUT_TYPE), ('model_id', Optional[str])])): __slots__ = () def __new__(cls, example, inference, model_id=None): return super().__new__(cls, example, inference, model_id)
PredictionResult.__doc__ = """A NamedTuple containing both input and output from the inference.""" PredictionResult.example.__doc__ = """The input example.""" PredictionResult.inference.__doc__ = """Results for the inference on the model for the given example.""" PredictionResult.model_id.__doc__ = """Model ID used to run the prediction."""
[docs]class ModelMetadata(NamedTuple): model_id: str model_name: str
[docs]class RunInferenceDLQ(NamedTuple): failed_inferences: beam.PCollection failed_preprocessing: Sequence[beam.PCollection] failed_postprocessing: Sequence[beam.PCollection]
class _ModelLoadStats(NamedTuple): model_tag: str load_latency: Optional[int] byte_size: Optional[int] ModelMetadata.model_id.__doc__ = """Unique identifier for the model. This can be a file path or a URL where the model can be accessed. It is used to load the model for inference.""" ModelMetadata.model_name.__doc__ = """Human-readable name for the model. This can be used to identify the model in the metrics generated by the RunInference transform.""" def _to_milliseconds(time_ns: int) -> int: return int(time_ns / _NANOSECOND_TO_MILLISECOND) def _to_microseconds(time_ns: int) -> int: return int(time_ns / _NANOSECOND_TO_MICROSECOND)
[docs]@dataclass(frozen=True) class KeyModelPathMapping(Generic[KeyT]): """ Dataclass for mapping 1 or more keys to 1 model path. This is used in conjunction with a KeyedModelHandler with many model handlers to update a set of keys' model handlers with the new path. Given `KeyModelPathMapping(keys: ['key1', 'key2'], update_path: 'updated/path', model_id: 'id1')`, all examples with keys `key1` or `key2` will have their corresponding model handler's update_model function called with 'updated/path' and their metrics will correspond with 'id1'. For more information see the KeyedModelHandler documentation https://beam.apache.org/releases/pydoc/current/apache_beam.ml.inference.base.html#apache_beam.ml.inference.base.KeyedModelHandler documentation and the website section on model updates https://beam.apache.org/documentation/sdks/python-machine-learning/#automatic-model-refresh """ keys: List[KeyT] update_path: str model_id: str = ''
[docs]class ModelHandler(Generic[ExampleT, PredictionT, ModelT]): """Has the ability to load and apply an ML model.""" def __init__(self): """Environment variables are set using a dict named 'env_vars' before loading the model. Child classes can accept this dict as a kwarg.""" self._env_vars = {}
[docs] def load_model(self) -> ModelT: """Loads and initializes a model for processing.""" raise NotImplementedError(type(self))
[docs] def run_inference( self, batch: Sequence[ExampleT], model: ModelT, inference_args: Optional[Dict[str, Any]] = None) -> Iterable[PredictionT]: """Runs inferences on a batch of examples. Args: batch: A sequence of examples or features. model: The model used to make inferences. inference_args: Extra arguments for models whose inference call requires extra parameters. Returns: An Iterable of Predictions. """ raise NotImplementedError(type(self))
[docs] def get_num_bytes(self, batch: Sequence[ExampleT]) -> int: """ Returns: The number of bytes of data for a batch. """ return len(pickle.dumps(batch))
[docs] def get_metrics_namespace(self) -> str: """ Returns: A namespace for metrics collected by the RunInference transform. """ return 'RunInference'
[docs] def get_resource_hints(self) -> dict: """ Returns: Resource hints for the transform. """ return {}
[docs] def batch_elements_kwargs(self) -> Mapping[str, Any]: """ Returns: kwargs suitable for beam.BatchElements. """ return {}
[docs] def validate_inference_args(self, inference_args: Optional[Dict[str, Any]]): """Validates inference_args passed in the inference call. Because most frameworks do not need extra arguments in their predict() call, the default behavior is to error out if inference_args are present. """ if inference_args: raise ValueError( 'inference_args were provided, but should be None because this ' 'framework does not expect extra arguments on inferences.')
[docs] def update_model_path(self, model_path: Optional[str] = None): """ Update the model path produced by side inputs. update_model_path should be used when a ModelHandler represents a single model, not multiple models. This will be true in most cases. For more information see the website section on model updates https://beam.apache.org/documentation/sdks/python-machine-learning/#automatic-model-refresh """ pass
[docs] def update_model_paths( self, model: ModelT, model_paths: Optional[Union[str, List[KeyModelPathMapping]]] = None): """ Update the model paths produced by side inputs. update_model_paths should be used when updating multiple models at once (e.g. when using a KeyedModelHandler that holds multiple models). For more information see the KeyedModelHandler documentation https://beam.apache.org/releases/pydoc/current/apache_beam.ml.inference.base.html#apache_beam.ml.inference.base.KeyedModelHandler documentation and the website section on model updates https://beam.apache.org/documentation/sdks/python-machine-learning/#automatic-model-refresh """ pass
[docs] def get_preprocess_fns(self) -> Iterable[Callable[[Any], Any]]: """Gets all preprocessing functions to be run before batching/inference. Functions are in order that they should be applied.""" return []
[docs] def get_postprocess_fns(self) -> Iterable[Callable[[Any], Any]]: """Gets all postprocessing functions to be run after inference. Functions are in order that they should be applied.""" return []
[docs] def set_environment_vars(self): """Sets environment variables using a dictionary provided via kwargs. Keys are the env variable name, and values are the env variable value. Child ModelHandler classes should set _env_vars via kwargs in __init__, or else call super().__init__().""" env_vars = getattr(self, '_env_vars', {}) for env_variable, env_value in env_vars.items(): os.environ[env_variable] = env_value
[docs] def with_preprocess_fn( self, fn: Callable[[PreProcessT], ExampleT] ) -> 'ModelHandler[PreProcessT, PredictionT, ModelT, PreProcessT]': """Returns a new ModelHandler with a preprocessing function associated with it. The preprocessing function will be run before batching/inference and should map your input PCollection to the base ModelHandler's input type. If you apply multiple preprocessing functions, they will be run on your original PCollection in order from last applied to first applied.""" return _PreProcessingModelHandler(self, fn)
[docs] def with_postprocess_fn( self, fn: Callable[[PredictionT], PostProcessT] ) -> 'ModelHandler[ExampleT, PostProcessT, ModelT, PostProcessT]': """Returns a new ModelHandler with a postprocessing function associated with it. The postprocessing function will be run after inference and should map the base ModelHandler's output type to your desired output type. If you apply multiple postprocessing functions, they will be run on your original inference result in order from first applied to last applied.""" return _PostProcessingModelHandler(self, fn)
[docs] def share_model_across_processes(self) -> bool: """Returns a boolean representing whether or not a model should be shared across multiple processes instead of being loaded per process. This is primary useful for large models that can't fit multiple copies in memory. Multi-process support may vary by runner, but this will fallback to loading per process as necessary. See https://beam.apache.org/releases/pydoc/current/apache_beam.utils.multi_process_shared.html""" return False
[docs] def override_metrics(self, metrics_namespace: str = '') -> bool: """Returns a boolean representing whether or not a model handler will override metrics reporting. If True, RunInference will not report any metrics.""" return False
class _ModelManager: """ A class for efficiently managing copies of multiple models. Will load a single copy of each model into a multi_process_shared object and then return a lookup key for that object. """ def __init__(self, mh_map: Dict[str, ModelHandler]): """ Args: mh_map: A map from keys to model handlers which can be used to load a model. """ self._max_models = None # Map keys to model handlers self._mh_map: Dict[str, ModelHandler] = mh_map # Map keys to the last updated model path for that key self._key_to_last_update: Dict[str, str] = defaultdict(str) # Map key for a model to a unique tag that will persist for the life of # that model in memory. A new tag will be generated if a model is swapped # out of memory and reloaded. self._tag_map: Dict[str, str] = OrderedDict() # Map a tag to a multiprocessshared model object for that tag. Each entry # of this map should last as long as the corresponding entry in _tag_map. self._proxy_map: Dict[str, multi_process_shared.MultiProcessShared] = {} def load(self, key: str) -> _ModelLoadStats: """ Loads the appropriate model for the given key into memory. Args: key: the key associated with the model we'd like to load. Returns: _ModelLoadStats with tag, byte size, and latency to load the model. If the model was already loaded, byte size/latency will be None. """ # Map the key for a model to a unique tag that will persist until the model # is released. This needs to be unique between releasing/reacquiring th # model because otherwise the ProxyManager will try to reuse the model that # has been released and deleted. if key in self._tag_map: self._tag_map.move_to_end(key) return _ModelLoadStats(self._tag_map[key], None, None) else: self._tag_map[key] = uuid.uuid4().hex tag = self._tag_map[key] mh = self._mh_map[key] if self._max_models is not None and self._max_models < len(self._tag_map): # If we're about to exceed our LRU size, release the last used model. tag_to_remove = self._tag_map.popitem(last=False)[1] shared_handle, model_to_remove = self._proxy_map[tag_to_remove] shared_handle.release(model_to_remove) del self._proxy_map[tag_to_remove] # Load the new model memory_before = _get_current_process_memory_in_bytes() start_time = _to_milliseconds(time.time_ns()) shared_handle = multi_process_shared.MultiProcessShared( mh.load_model, tag=tag) model_reference = shared_handle.acquire() self._proxy_map[tag] = (shared_handle, model_reference) memory_after = _get_current_process_memory_in_bytes() end_time = _to_milliseconds(time.time_ns()) return _ModelLoadStats( tag, end_time - start_time, memory_after - memory_before) def increment_max_models(self, increment: int): """ Increments the number of models that this instance of a _ModelManager is able to hold. If it is never called, no limit is imposed. Args: increment: the amount by which we are incrementing the number of models. """ if self._max_models is None: self._max_models = 0 self._max_models += increment def update_model_handler(self, key: str, model_path: str, previous_key: str): """ Updates the model path of this model handler and removes it from memory so that it can be reloaded with the updated path. No-ops if no model update needs to be applied. Args: key: the key associated with the model we'd like to update. model_path: the new path to the model we'd like to load. previous_key: the key that is associated with the old version of this model. This will often be the same as the current key, but sometimes we will want to keep both the old and new models to serve different cohorts. In that case, the keys should be different. """ if self._key_to_last_update[key] == model_path: return self._key_to_last_update[key] = model_path if key not in self._mh_map: self._mh_map[key] = deepcopy(self._mh_map[previous_key]) self._mh_map[key].update_model_path(model_path) if key in self._tag_map: tag_to_remove = self._tag_map[key] shared_handle, model_to_remove = self._proxy_map[tag_to_remove] shared_handle.release(model_to_remove) del self._tag_map[key] del self._proxy_map[tag_to_remove] # Use a dataclass instead of named tuple because NamedTuples and generics don't # mix well across the board for all versions: # https://github.com/python/typing/issues/653
[docs]class KeyModelMapping(Generic[KeyT, ExampleT, PredictionT, ModelT]): """ Dataclass for mapping 1 or more keys to 1 model handler. Given `KeyModelMapping(['key1', 'key2'], myMh)`, all examples with keys `key1` or `key2` will be run against the model defined by the `myMh` ModelHandler. """ def __init__( self, keys: List[KeyT], mh: ModelHandler[ExampleT, PredictionT, ModelT]): self.keys = keys self.mh = mh
[docs]class KeyedModelHandler(Generic[KeyT, ExampleT, PredictionT, ModelT], ModelHandler[Tuple[KeyT, ExampleT], Tuple[KeyT, PredictionT], Union[ModelT, _ModelManager]]): def __init__( self, unkeyed: Union[ModelHandler[ExampleT, PredictionT, ModelT], List[KeyModelMapping[KeyT, ExampleT, PredictionT, ModelT]]], max_models_per_worker_hint: Optional[int] = None): """A ModelHandler that takes keyed examples and returns keyed predictions. For example, if the original model is used with RunInference to take a PCollection[E] to a PCollection[P], this ModelHandler would take a PCollection[Tuple[K, E]] to a PCollection[Tuple[K, P]], making it possible to use the key to associate the outputs with the inputs. KeyedModelHandler is able to accept either a single unkeyed ModelHandler or many different model handlers corresponding to the keys for which that ModelHandler should be used. For example, the following configuration could be used to map keys 1-3 to ModelHandler1 and keys 4-5 to ModelHandler2: k1 = ['k1', 'k2', 'k3'] k2 = ['k4', 'k5'] KeyedModelHandler([KeyModelMapping(k1, mh1), KeyModelMapping(k2, mh2)]) Note that a single copy of each of these models may all be held in memory at the same time; be careful not to load too many large models or your pipeline may cause Out of Memory exceptions. KeyedModelHandlers support Automatic Model Refresh to update your model to a newer version without stopping your streaming pipeline. For an overview of this feature, see https://beam.apache.org/documentation/sdks/python-machine-learning/#automatic-model-refresh To use this feature with a KeyedModelHandler that has many models per key, you can pass in a list of KeyModelPathMapping objects to define your new model paths. For example, passing in the side input of [KeyModelPathMapping(keys=['k1', 'k2'], update_path='update/path/1'), KeyModelPathMapping(keys=['k3'], update_path='update/path/2')] will update the model corresponding to keys 'k1' and 'k2' with path 'update/path/1' and the model corresponding to 'k3' with 'update/path/2'. In order to do a side input update: (1) all restrictions mentioned in https://beam.apache.org/documentation/sdks/python-machine-learning/#automatic-model-refresh must be met, (2) all update_paths must be non-empty, even if they are not being updated from their original values, and (3) the set of keys originally defined cannot change. This means that if originally you have defined model handlers for 'key1', 'key2', and 'key3', all 3 of those keys must appear in your list of KeyModelPathMappings exactly once. No additional keys can be added. When using many models defined per key, metrics about inference and model loading will be gathered on an aggregate basis for all keys. These will be reported with no prefix. Metrics will also be gathered on a per key basis. Since some keys can share the same model, only one set of metrics will be reported per key 'cohort'. These will be reported in the form: `<cohort_key>-<metric_name>`, where `<cohort_key>` can be any key selected from the cohort. When model updates occur, the metrics will be reported in the form `<cohort_key>-<model id>-<metric_name>`. Args: unkeyed: Either (a) an implementation of ModelHandler that does not require keys or (b) a list of KeyModelMappings mapping lists of keys to unkeyed ModelHandlers. max_models_per_worker_hint: A hint to the runner indicating how many models can be held in memory at one time per worker process. For example, if your worker has 8 GB of memory provisioned and your workers take up 1 GB each, you should set this to 7 to allow all models to sit in memory with some buffer. """ self._metrics_collectors: Dict[str, _MetricsCollector] = {} self._default_metrics_collector: _MetricsCollector = None self._metrics_namespace = '' self._single_model = not isinstance(unkeyed, list) if self._single_model: if len(unkeyed.get_preprocess_fns()) or len( unkeyed.get_postprocess_fns()): raise Exception( 'Cannot make make an unkeyed model handler with pre or ' 'postprocessing functions defined into a keyed model handler. All ' 'pre/postprocessing functions must be defined on the outer model' 'handler.') self._env_vars = unkeyed._env_vars self._unkeyed = unkeyed return self._max_models_per_worker_hint = max_models_per_worker_hint # To maintain an efficient representation, we will map all keys in a given # KeyModelMapping to a single id (the first key in the KeyModelMapping # list). We will then map that key to a ModelHandler. This will allow us to # quickly look up the appropriate ModelHandler for any given key. self._id_to_mh_map: Dict[str, ModelHandler[ExampleT, PredictionT, ModelT]] = {} self._key_to_id_map: Dict[str, str] = {} for mh_tuple in unkeyed: mh = mh_tuple.mh keys = mh_tuple.keys if len(mh.get_preprocess_fns()) or len(mh.get_postprocess_fns()): raise ValueError( 'Cannot use an unkeyed model handler with pre or ' 'postprocessing functions defined in a keyed model handler. All ' 'pre/postprocessing functions must be defined on the outer model' 'handler.') hints = mh.get_resource_hints() if len(hints) > 0: logging.warning( 'mh %s defines the following resource hints, which will be' 'ignored: %s. Resource hints are not respected when more than one ' 'model handler is used in a KeyedModelHandler. If you would like ' 'to specify resource hints, you can do so by overriding the ' 'KeyedModelHandler.get_resource_hints() method.', mh, hints) batch_kwargs = mh.batch_elements_kwargs() if len(batch_kwargs) > 0: logging.warning( 'mh %s defines the following batching kwargs which will be ' 'ignored %s. Batching kwargs are not respected when ' 'more than one model handler is used in a KeyedModelHandler. If ' 'you would like to specify resource hints, you can do so by ' 'overriding the KeyedModelHandler.batch_elements_kwargs() method.', hints, batch_kwargs) env_vars = mh._env_vars if len(env_vars) > 0: logging.warning( 'mh %s defines the following _env_vars which will be ignored %s. ' '_env_vars are not respected when more than one model handler is ' 'used in a KeyedModelHandler. If you need env vars set at ' 'inference time, you can do so with ' 'a custom inference function.', mh, env_vars) if len(keys) == 0: raise ValueError( f'Empty list maps to model handler {mh}. All model handlers must ' 'have one or more associated keys.') self._id_to_mh_map[keys[0]] = mh for key in keys: if key in self._key_to_id_map: raise ValueError( f'key {key} maps to multiple model handlers. All keys must map ' 'to exactly one model handler.') self._key_to_id_map[key] = keys[0]
[docs] def load_model(self) -> Union[ModelT, _ModelManager]: if self._single_model: return self._unkeyed.load_model() return _ModelManager(self._id_to_mh_map)
[docs] def run_inference( self, batch: Sequence[Tuple[KeyT, ExampleT]], model: Union[ModelT, _ModelManager], inference_args: Optional[Dict[str, Any]] = None ) -> Iterable[Tuple[KeyT, PredictionT]]: if self._single_model: keys, unkeyed_batch = zip(*batch) return zip( keys, self._unkeyed.run_inference(unkeyed_batch, model, inference_args)) # The first time a MultiProcessShared ModelManager is used for inference # from this process, we should increment its max model count if self._max_models_per_worker_hint is not None: lock = threading.Lock() if lock.acquire(blocking=False): model.increment_max_models(self._max_models_per_worker_hint) self._max_models_per_worker_hint = None batch_by_key = defaultdict(list) key_by_id = defaultdict(set) for key, example in batch: batch_by_key[key].append(example) key_by_id[self._key_to_id_map[key]].add(key) predictions = [] for id, keys in key_by_id.items(): mh = self._id_to_mh_map[id] loaded_model = model.load(id) keyed_model_tag = loaded_model.model_tag if loaded_model.byte_size is not None: self._metrics_collectors[id].update_load_model_metrics( loaded_model.load_latency, loaded_model.byte_size) self._default_metrics_collector.update_load_model_metrics( loaded_model.load_latency, loaded_model.byte_size) keyed_model_shared_handle = multi_process_shared.MultiProcessShared( mh.load_model, tag=keyed_model_tag) keyed_model = keyed_model_shared_handle.acquire() start_time = _to_microseconds(time.time_ns()) num_bytes = 0 num_elements = 0 try: for key in keys: unkeyed_batches = batch_by_key[key] try: for inf in mh.run_inference(unkeyed_batches, keyed_model, inference_args): predictions.append((key, inf)) except BaseException as e: self._metrics_collectors[id].failed_batches_counter.inc() self._default_metrics_collector.failed_batches_counter.inc() raise e num_bytes += mh.get_num_bytes(unkeyed_batches) num_elements += len(unkeyed_batches) finally: keyed_model_shared_handle.release(keyed_model) end_time = _to_microseconds(time.time_ns()) inference_latency = end_time - start_time self._metrics_collectors[id].update( num_elements, num_bytes, inference_latency) self._default_metrics_collector.update( num_elements, num_bytes, inference_latency) return predictions
[docs] def get_num_bytes(self, batch: Sequence[Tuple[KeyT, ExampleT]]) -> int: keys, unkeyed_batch = zip(*batch) batch_bytes = len(pickle.dumps(keys)) if self._single_model: return batch_bytes + self._unkeyed.get_num_bytes(unkeyed_batch) batch_by_key = defaultdict(list) for key, examples in batch: batch_by_key[key].append(examples) for key, examples in batch_by_key.items(): mh_id = self._key_to_id_map[key] batch_bytes += self._id_to_mh_map[mh_id].get_num_bytes(examples) return batch_bytes
[docs] def get_metrics_namespace(self) -> str: if self._single_model: return self._unkeyed.get_metrics_namespace() return 'BeamML_KeyedModels'
[docs] def get_resource_hints(self): if self._single_model: return self._unkeyed.get_resource_hints() return {}
[docs] def batch_elements_kwargs(self): if self._single_model: return self._unkeyed.batch_elements_kwargs() return {}
[docs] def validate_inference_args(self, inference_args: Optional[Dict[str, Any]]): if self._single_model: return self._unkeyed.validate_inference_args(inference_args) for mh in self._id_to_mh_map.values(): mh.validate_inference_args(inference_args)
[docs] def update_model_paths( self, model: Union[ModelT, _ModelManager], model_paths: List[KeyModelPathMapping[KeyT]] = None): # When there are many models, the keyed model handler is responsible for # reorganizing the model handlers into cohorts and telling the model # manager to update every cohort's associated model handler. The model # manager is responsible for performing the updates and tracking which # updates have already been applied. if model_paths is None or len(model_paths) == 0 or model is None: return if self._single_model: raise RuntimeError( 'Invalid model update: sent many model paths to ' 'update, but KeyedModelHandler is wrapping a single ' 'model.') # Map cohort ids to a dictionary mapping new model paths to the keys that # were originally in that cohort. We will use this to construct our new # cohorts. # cohort_path_mapping will be structured as follows: # { # original_cohort_id: { # 'update/path/1': ['key1FromOriginalCohort', key2FromOriginalCohort'], # 'update/path/2': ['key3FromOriginalCohort', key4FromOriginalCohort'], # } # } cohort_path_mapping: Dict[KeyT, Dict[str, List[KeyT]]] = {} key_modelid_mapping: Dict[KeyT, str] = {} seen_keys = set() for mp in model_paths: keys = mp.keys update_path = mp.update_path model_id = mp.model_id if len(update_path) == 0: raise ValueError(f'Invalid model update, path for {keys} is empty') for key in keys: if key in seen_keys: raise ValueError( f'Invalid model update: {key} appears in multiple ' 'update lists. A single model update must provide exactly one ' 'updated path per key.') seen_keys.add(key) if key not in self._key_to_id_map: raise ValueError( f'Invalid model update: {key} appears in ' 'update, but not in the original configuration.') key_modelid_mapping[key] = model_id cohort_id = self._key_to_id_map[key] if cohort_id not in cohort_path_mapping: cohort_path_mapping[cohort_id] = defaultdict(list) cohort_path_mapping[cohort_id][update_path].append(key) for key in self._key_to_id_map: if key not in seen_keys: raise ValueError( f'Invalid model update: {key} appears in the ' 'original configuration, but not the update.') # We now have our new set of cohorts. For each one, update our local model # handler configuration and send the results to the ModelManager for old_cohort_id, path_key_mapping in cohort_path_mapping.items(): for updated_path, keys in path_key_mapping.items(): cohort_id = old_cohort_id if old_cohort_id not in keys: # Create new cohort cohort_id = keys[0] for key in keys: self._key_to_id_map[key] = cohort_id mh = self._id_to_mh_map[old_cohort_id] self._id_to_mh_map[cohort_id] = deepcopy(mh) self._id_to_mh_map[cohort_id].update_model_path(updated_path) model.update_model_handler(cohort_id, updated_path, old_cohort_id) model_id = key_modelid_mapping[cohort_id] self._metrics_collectors[cohort_id] = _MetricsCollector( self._metrics_namespace, f'{cohort_id}-{model_id}-')
[docs] def update_model_path(self, model_path: Optional[str] = None): if self._single_model: return self._unkeyed.update_model_path(model_path=model_path) if model_path is not None: raise RuntimeError( 'Model updates are currently not supported for ' + 'KeyedModelHandlers with multiple different per-key ' + 'ModelHandlers.')
[docs] def share_model_across_processes(self) -> bool: if self._single_model: return self._unkeyed.share_model_across_processes() return True
[docs] def override_metrics(self, metrics_namespace: str = '') -> bool: if self._single_model: return self._unkeyed.override_metrics(metrics_namespace) self._metrics_namespace = metrics_namespace self._default_metrics_collector = _MetricsCollector(metrics_namespace) for cohort_id in self._id_to_mh_map: self._metrics_collectors[cohort_id] = _MetricsCollector( metrics_namespace, f'{cohort_id}-') return True
[docs]class MaybeKeyedModelHandler(Generic[KeyT, ExampleT, PredictionT, ModelT], ModelHandler[Union[ExampleT, Tuple[KeyT, ExampleT]], Union[PredictionT, Tuple[KeyT, PredictionT]], ModelT]): def __init__(self, unkeyed: ModelHandler[ExampleT, PredictionT, ModelT]): """A ModelHandler that takes examples that might have keys and returns predictions that might have keys. For example, if the original model is used with RunInference to take a PCollection[E] to a PCollection[P], this ModelHandler would take either PCollection[E] to a PCollection[P] or PCollection[Tuple[K, E]] to a PCollection[Tuple[K, P]], depending on the whether the elements are tuples. This pattern makes it possible to associate the outputs with the inputs based on the key. Note that you cannot use this ModelHandler if E is a tuple type. In addition, either all examples should be keyed, or none of them. Args: unkeyed: An implementation of ModelHandler that does not require keys. """ if len(unkeyed.get_preprocess_fns()) or len(unkeyed.get_postprocess_fns()): raise Exception( 'Cannot make make an unkeyed model handler with pre or ' 'postprocessing functions defined into a keyed model handler. All ' 'pre/postprocessing functions must be defined on the outer model' 'handler.') self._unkeyed = unkeyed self._env_vars = unkeyed._env_vars
[docs] def load_model(self) -> ModelT: return self._unkeyed.load_model()
[docs] def run_inference( self, batch: Sequence[Union[ExampleT, Tuple[KeyT, ExampleT]]], model: ModelT, inference_args: Optional[Dict[str, Any]] = None ) -> Union[Iterable[PredictionT], Iterable[Tuple[KeyT, PredictionT]]]: # Really the input should be # Union[Sequence[ExampleT], Sequence[Tuple[KeyT, ExampleT]]] # but there's not a good way to express (or check) that. if isinstance(batch[0], tuple): is_keyed = True keys, unkeyed_batch = zip(*batch) # type: ignore[arg-type] else: is_keyed = False unkeyed_batch = batch # type: ignore[assignment] unkeyed_results = self._unkeyed.run_inference( unkeyed_batch, model, inference_args) if is_keyed: return zip(keys, unkeyed_results) else: return unkeyed_results
[docs] def get_num_bytes( self, batch: Sequence[Union[ExampleT, Tuple[KeyT, ExampleT]]]) -> int: # MyPy can't follow the branching logic. if isinstance(batch[0], tuple): keys, unkeyed_batch = zip(*batch) # type: ignore[arg-type] return len( pickle.dumps(keys)) + self._unkeyed.get_num_bytes(unkeyed_batch) else: return self._unkeyed.get_num_bytes(batch) # type: ignore[arg-type]
[docs] def get_metrics_namespace(self) -> str: return self._unkeyed.get_metrics_namespace()
[docs] def get_resource_hints(self): return self._unkeyed.get_resource_hints()
[docs] def batch_elements_kwargs(self): return self._unkeyed.batch_elements_kwargs()
[docs] def validate_inference_args(self, inference_args: Optional[Dict[str, Any]]): return self._unkeyed.validate_inference_args(inference_args)
[docs] def update_model_path(self, model_path: Optional[str] = None): return self._unkeyed.update_model_path(model_path=model_path)
[docs] def get_preprocess_fns(self) -> Iterable[Callable[[Any], Any]]: return self._unkeyed.get_preprocess_fns()
[docs] def get_postprocess_fns(self) -> Iterable[Callable[[Any], Any]]: return self._unkeyed.get_postprocess_fns()
[docs] def share_model_across_processes(self) -> bool: return self._unkeyed.share_model_across_processes()
class _PreProcessingModelHandler(Generic[ExampleT, PredictionT, ModelT, PreProcessT], ModelHandler[PreProcessT, PredictionT, ModelT]): def __init__( self, base: ModelHandler[ExampleT, PredictionT, ModelT], preprocess_fn: Callable[[PreProcessT], ExampleT]): """A ModelHandler that has a preprocessing function associated with it. Args: base: An implementation of the underlying model handler. preprocess_fn: the preprocessing function to use. """ self._base = base self._env_vars = base._env_vars self._preprocess_fn = preprocess_fn def load_model(self) -> ModelT: return self._base.load_model() def run_inference( self, batch: Sequence[Union[ExampleT, Tuple[KeyT, ExampleT]]], model: ModelT, inference_args: Optional[Dict[str, Any]] = None ) -> Union[Iterable[PredictionT], Iterable[Tuple[KeyT, PredictionT]]]: return self._base.run_inference(batch, model, inference_args) def get_num_bytes( self, batch: Sequence[Union[ExampleT, Tuple[KeyT, ExampleT]]]) -> int: return self._base.get_num_bytes(batch) def get_metrics_namespace(self) -> str: return self._base.get_metrics_namespace() def get_resource_hints(self): return self._base.get_resource_hints() def batch_elements_kwargs(self): return self._base.batch_elements_kwargs() def validate_inference_args(self, inference_args: Optional[Dict[str, Any]]): return self._base.validate_inference_args(inference_args) def update_model_path(self, model_path: Optional[str] = None): return self._base.update_model_path(model_path=model_path) def get_preprocess_fns(self) -> Iterable[Callable[[Any], Any]]: return [self._preprocess_fn] + self._base.get_preprocess_fns() def get_postprocess_fns(self) -> Iterable[Callable[[Any], Any]]: return self._base.get_postprocess_fns() class _PostProcessingModelHandler(Generic[ExampleT, PredictionT, ModelT, PostProcessT], ModelHandler[ExampleT, PostProcessT, ModelT]): def __init__( self, base: ModelHandler[ExampleT, PredictionT, ModelT], postprocess_fn: Callable[[PredictionT], PostProcessT]): """A ModelHandler that has a preprocessing function associated with it. Args: base: An implementation of the underlying model handler. postprocess_fn: the preprocessing function to use. """ self._base = base self._env_vars = base._env_vars self._postprocess_fn = postprocess_fn def load_model(self) -> ModelT: return self._base.load_model() def run_inference( self, batch: Sequence[Union[ExampleT, Tuple[KeyT, ExampleT]]], model: ModelT, inference_args: Optional[Dict[str, Any]] = None ) -> Union[Iterable[PredictionT], Iterable[Tuple[KeyT, PredictionT]]]: return self._base.run_inference(batch, model, inference_args) def get_num_bytes( self, batch: Sequence[Union[ExampleT, Tuple[KeyT, ExampleT]]]) -> int: return self._base.get_num_bytes(batch) def get_metrics_namespace(self) -> str: return self._base.get_metrics_namespace() def get_resource_hints(self): return self._base.get_resource_hints() def batch_elements_kwargs(self): return self._base.batch_elements_kwargs() def validate_inference_args(self, inference_args: Optional[Dict[str, Any]]): return self._base.validate_inference_args(inference_args) def update_model_path(self, model_path: Optional[str] = None): return self._base.update_model_path(model_path=model_path) def get_preprocess_fns(self) -> Iterable[Callable[[Any], Any]]: return self._base.get_preprocess_fns() def get_postprocess_fns(self) -> Iterable[Callable[[Any], Any]]: return self._base.get_postprocess_fns() + [self._postprocess_fn]
[docs]class RunInference(beam.PTransform[beam.PCollection[ExampleT], beam.PCollection[PredictionT]]): def __init__( self, model_handler: ModelHandler[ExampleT, PredictionT, Any], clock=time, inference_args: Optional[Dict[str, Any]] = None, metrics_namespace: Optional[str] = None, *, model_metadata_pcoll: beam.PCollection[ModelMetadata] = None, watch_model_pattern: Optional[str] = None, **kwargs): """ A transform that takes a PCollection of examples (or features) for use on an ML model. The transform then outputs inferences (or predictions) for those examples in a PCollection of PredictionResults that contains the input examples and the output inferences. Models for supported frameworks can be loaded using a URI. Supported services can also be used. This transform attempts to batch examples using the beam.BatchElements transform. Batching can be configured using the ModelHandler. Args: model_handler: An implementation of ModelHandler. clock: A clock implementing time_ns. *Used for unit testing.* inference_args: Extra arguments for models whose inference call requires extra parameters. metrics_namespace: Namespace of the transform to collect metrics. model_metadata_pcoll: PCollection that emits Singleton ModelMetadata containing model path and model name, that is used as a side input to the _RunInferenceDoFn. watch_model_pattern: A glob pattern used to watch a directory for automatic model refresh. """ self._model_handler = model_handler self._inference_args = inference_args self._clock = clock self._metrics_namespace = metrics_namespace self._model_metadata_pcoll = model_metadata_pcoll self._enable_side_input_loading = self._model_metadata_pcoll is not None self._with_exception_handling = False self._watch_model_pattern = watch_model_pattern self._kwargs = kwargs # Generate a random tag to use for shared.py and multi_process_shared.py to # allow us to effectively disambiguate in multi-model settings. self._model_tag = uuid.uuid4().hex
[docs] def annotations(self): return { 'model_handler': str(self._model_handler), 'model_handler_type': ( f'{self._model_handler.__class__.__module__}' f'.{self._model_handler.__class__.__qualname__}'), **super().annotations() }
def _get_model_metadata_pcoll(self, pipeline): # avoid circular imports. # pylint: disable=wrong-import-position from apache_beam.ml.inference.utils import WatchFilePattern extra_params = {} if 'interval' in self._kwargs: extra_params['interval'] = self._kwargs['interval'] if 'stop_timestamp' in self._kwargs: extra_params['stop_timestamp'] = self._kwargs['stop_timestamp'] return ( pipeline | WatchFilePattern( file_pattern=self._watch_model_pattern, **extra_params)) # TODO(BEAM-14046): Add and link to help documentation.
[docs] @classmethod def from_callable(cls, model_handler_provider, **kwargs): """Multi-language friendly constructor. Use this constructor with fully_qualified_named_transform to initialize the RunInference transform from PythonCallableSource provided by foreign SDKs. Args: model_handler_provider: A callable object that returns ModelHandler. kwargs: Keyword arguments for model_handler_provider. """ return cls(model_handler_provider(**kwargs))
def _apply_fns( self, pcoll: beam.PCollection, fns: Iterable[Callable[[Any], Any]], step_prefix: str) -> Tuple[beam.PCollection, Iterable[beam.PCollection]]: bad_preprocessed = [] for idx in range(len(fns)): fn = fns[idx] if self._with_exception_handling: pcoll, bad = (pcoll | f"{step_prefix}-{idx}" >> beam.Map( fn).with_exception_handling( exc_class=self._exc_class, use_subprocess=self._use_subprocess, threshold=self._threshold)) bad_preprocessed.append(bad) else: pcoll = pcoll | f"{step_prefix}-{idx}" >> beam.Map(fn) return pcoll, bad_preprocessed # TODO(https://github.com/apache/beam/issues/21447): Add batch_size back off # in the case there are functional reasons large batch sizes cannot be # handled.
[docs] def expand( self, pcoll: beam.PCollection[ExampleT]) -> beam.PCollection[PredictionT]: self._model_handler.validate_inference_args(self._inference_args) # DLQ pcollections bad_preprocessed = [] bad_inference = None bad_postprocessed = [] preprocess_fns = self._model_handler.get_preprocess_fns() postprocess_fns = self._model_handler.get_postprocess_fns() pcoll, bad_preprocessed = self._apply_fns( pcoll, preprocess_fns, 'BeamML_RunInference_Preprocess') resource_hints = self._model_handler.get_resource_hints() # check for the side input if self._watch_model_pattern: self._model_metadata_pcoll = self._get_model_metadata_pcoll( pcoll.pipeline) batched_elements_pcoll = ( pcoll # TODO(https://github.com/apache/beam/issues/21440): Hook into the # batching DoFn APIs. | beam.BatchElements(**self._model_handler.batch_elements_kwargs())) run_inference_pardo = beam.ParDo( _RunInferenceDoFn( self._model_handler, self._clock, self._metrics_namespace, self._enable_side_input_loading, self._model_tag), self._inference_args, beam.pvalue.AsSingleton( self._model_metadata_pcoll, ) if self._enable_side_input_loading else None).with_resource_hints( **resource_hints) if self._with_exception_handling: results, bad_inference = ( batched_elements_pcoll | 'BeamML_RunInference' >> run_inference_pardo.with_exception_handling( exc_class=self._exc_class, use_subprocess=self._use_subprocess, threshold=self._threshold)) else: results = ( batched_elements_pcoll | 'BeamML_RunInference' >> run_inference_pardo) results, bad_postprocessed = self._apply_fns( results, postprocess_fns, 'BeamML_RunInference_Postprocess') if self._with_exception_handling: dlq = RunInferenceDLQ(bad_inference, bad_preprocessed, bad_postprocessed) return results, dlq return results
[docs] def with_exception_handling( self, *, exc_class=Exception, use_subprocess=False, threshold=1): """Automatically provides a dead letter output for skipping bad records. This can allow a pipeline to continue successfully rather than fail or continuously throw errors on retry when bad elements are encountered. This returns a tagged output with two PCollections, the first being the results of successfully processing the input PCollection, and the second being the set of bad batches of records (those which threw exceptions during processing) along with information about the errors raised. For example, one would write:: main, other = RunInference( maybe_error_raising_model_handler ).with_exception_handling() and `main` will be a PCollection of PredictionResults and `other` will contain a `RunInferenceDLQ` object with PCollections containing failed records for each failed inference, preprocess operation, or postprocess operation. To access each collection of failed records, one would write: failed_inferences = other.failed_inferences failed_preprocessing = other.failed_preprocessing failed_postprocessing = other.failed_postprocessing failed_inferences is in the form PCollection[Tuple[failed batch, exception]]. failed_preprocessing is in the form list[PCollection[Tuple[failed record, exception]]]], where each element of the list corresponds to a preprocess function. These PCollections are in the same order that the preprocess functions are applied. failed_postprocessing is in the form List[PCollection[Tuple[failed record, exception]]]], where each element of the list corresponds to a postprocess function. These PCollections are in the same order that the postprocess functions are applied. Args: exc_class: An exception class, or tuple of exception classes, to catch. Optional, defaults to 'Exception'. use_subprocess: Whether to execute the DoFn logic in a subprocess. This allows one to recover from errors that can crash the calling process (e.g. from an underlying library causing a segfault), but is slower as elements and results must cross a process boundary. Note that this starts up a long-running process that is used to handle all the elements (until hard failure, which should be rare) rather than a new process per element, so the overhead should be minimal (and can be amortized if there's any per-process or per-bundle initialization that needs to be done). Optional, defaults to False. threshold: An upper bound on the ratio of records that can be bad before aborting the entire pipeline. Optional, defaults to 1.0 (meaning up to 100% of records can be bad and the pipeline will still succeed). """ self._with_exception_handling = True self._exc_class = exc_class self._use_subprocess = use_subprocess self._threshold = threshold return self
class _MetricsCollector: """ A metrics collector that tracks ML related performance and memory usage. """ def __init__(self, namespace: str, prefix: str = ''): """ Args: namespace: Namespace for the metrics. prefix: Unique identifier for metrics, used when models are updated using side input. """ # Metrics if prefix: prefix = f'{prefix}_' self._inference_counter = beam.metrics.Metrics.counter( namespace, prefix + 'num_inferences') self.failed_batches_counter = beam.metrics.Metrics.counter( namespace, prefix + 'failed_batches_counter') self._inference_request_batch_size = beam.metrics.Metrics.distribution( namespace, prefix + 'inference_request_batch_size') self._inference_request_batch_byte_size = ( beam.metrics.Metrics.distribution( namespace, prefix + 'inference_request_batch_byte_size')) # Batch inference latency in microseconds. self._inference_batch_latency_micro_secs = ( beam.metrics.Metrics.distribution( namespace, prefix + 'inference_batch_latency_micro_secs')) self._model_byte_size = beam.metrics.Metrics.distribution( namespace, prefix + 'model_byte_size') # Model load latency in milliseconds. self._load_model_latency_milli_secs = beam.metrics.Metrics.distribution( namespace, prefix + 'load_model_latency_milli_secs') # Metrics cache self._load_model_latency_milli_secs_cache = None self._model_byte_size_cache = None def update_metrics_with_cache(self): if self._load_model_latency_milli_secs_cache is not None: self._load_model_latency_milli_secs.update( self._load_model_latency_milli_secs_cache) self._load_model_latency_milli_secs_cache = None if self._model_byte_size_cache is not None: self._model_byte_size.update(self._model_byte_size_cache) self._model_byte_size_cache = None def cache_load_model_metrics(self, load_model_latency_ms, model_byte_size): self._load_model_latency_milli_secs_cache = load_model_latency_ms self._model_byte_size_cache = model_byte_size def update_load_model_metrics(self, load_model_latency_ms, model_byte_size): self._load_model_latency_milli_secs.update(load_model_latency_ms) self._model_byte_size.update(model_byte_size) def update( self, examples_count: int, examples_byte_size: int, latency_micro_secs: int): self._inference_batch_latency_micro_secs.update(latency_micro_secs) self._inference_counter.inc(examples_count) self._inference_request_batch_size.update(examples_count) self._inference_request_batch_byte_size.update(examples_byte_size) class _RunInferenceDoFn(beam.DoFn, Generic[ExampleT, PredictionT]): def __init__( self, model_handler: ModelHandler[ExampleT, PredictionT, Any], clock, metrics_namespace, enable_side_input_loading: bool = False, model_tag: str = "RunInference"): """A DoFn implementation generic to frameworks. Args: model_handler: An implementation of ModelHandler. clock: A clock implementing time_ns. *Used for unit testing.* metrics_namespace: Namespace of the transform to collect metrics. enable_side_input_loading: Bool to indicate if model updates with side inputs. model_tag: Tag to use to disambiguate models in multi-model settings. """ self._model_handler = model_handler self._shared_model_handle = shared.Shared() self._clock = clock self._model = None self._metrics_namespace = metrics_namespace self._enable_side_input_loading = enable_side_input_loading self._side_input_path = None self._model_tag = model_tag def _load_model( self, side_input_model_path: Optional[Union[str, List[KeyModelPathMapping]]] = None): def load(): """Function for constructing shared LoadedModel.""" memory_before = _get_current_process_memory_in_bytes() start_time = _to_milliseconds(self._clock.time_ns()) if isinstance(side_input_model_path, str): self._model_handler.update_model_path(side_input_model_path) else: self._model_handler.update_model_paths( self._model, side_input_model_path) model = self._model_handler.load_model() end_time = _to_milliseconds(self._clock.time_ns()) memory_after = _get_current_process_memory_in_bytes() load_model_latency_ms = end_time - start_time model_byte_size = memory_after - memory_before if self._metrics_collector: self._metrics_collector.cache_load_model_metrics( load_model_latency_ms, model_byte_size) return model # TODO(https://github.com/apache/beam/issues/21443): Investigate releasing # model. model_tag = self._model_tag if isinstance(side_input_model_path, str) and side_input_model_path != '': model_tag = side_input_model_path if self._model_handler.share_model_across_processes(): model = multi_process_shared.MultiProcessShared( load, tag=model_tag, always_proxy=True).acquire() else: model = self._shared_model_handle.acquire(load, tag=model_tag) # since shared_model_handle is shared across threads, the model path # might not get updated in the model handler # because we directly get cached weak ref model from shared cache, instead # of calling load(). For sanity check, call update_model_path again. if isinstance(side_input_model_path, str): self._model_handler.update_model_path(side_input_model_path) else: self._model_handler.update_model_paths(self._model, side_input_model_path) return model def get_metrics_collector(self, prefix: str = ''): """ Args: prefix: Unique identifier for metrics, used when models are updated using side input. """ metrics_namespace = ( self._metrics_namespace) if self._metrics_namespace else ( self._model_handler.get_metrics_namespace()) if self._model_handler.override_metrics(metrics_namespace): return None return _MetricsCollector(metrics_namespace, prefix=prefix) def setup(self): self._metrics_collector = self.get_metrics_collector() self._model_handler.set_environment_vars() if not self._enable_side_input_loading: self._model = self._load_model() def update_model( self, side_input_model_path: Optional[Union[str, List[KeyModelPathMapping]]] = None): self._model = self._load_model(side_input_model_path=side_input_model_path) def _run_inference(self, batch, inference_args): start_time = _to_microseconds(self._clock.time_ns()) try: result_generator = self._model_handler.run_inference( batch, self._model, inference_args) except BaseException as e: if self._metrics_collector: self._metrics_collector.failed_batches_counter.inc() raise e predictions = list(result_generator) end_time = _to_microseconds(self._clock.time_ns()) inference_latency = end_time - start_time num_bytes = self._model_handler.get_num_bytes(batch) num_elements = len(batch) if self._metrics_collector: self._metrics_collector.update(num_elements, num_bytes, inference_latency) return predictions def process( self, batch, inference_args, si_model_metadata: Optional[Union[ModelMetadata, List[ModelMetadata], List[KeyModelPathMapping]]]): """ When side input is enabled: The method checks if the side input model has been updated, and if so, updates the model and runs inference on the batch of data. If the side input is empty or the model has not been updated, the method simply runs inference on the batch of data. """ if not si_model_metadata: return self._run_inference(batch, inference_args) if isinstance(si_model_metadata, beam.pvalue.EmptySideInput): self.update_model(side_input_model_path=None) elif isinstance(si_model_metadata, List) and hasattr(si_model_metadata[0], 'keys'): # TODO(https://github.com/apache/beam/issues/27628): Update metrics here self.update_model(si_model_metadata) elif self._side_input_path != si_model_metadata.model_id: self._side_input_path = si_model_metadata.model_id self._metrics_collector = self.get_metrics_collector( prefix=si_model_metadata.model_name) with threading.Lock(): self.update_model(si_model_metadata.model_id) return self._run_inference(batch, inference_args) return self._run_inference(batch, inference_args) def finish_bundle(self): # TODO(https://github.com/apache/beam/issues/21435): Figure out why there # is a cache. if self._metrics_collector: self._metrics_collector.update_metrics_with_cache() def _is_darwin() -> bool: return sys.platform == 'darwin' def _get_current_process_memory_in_bytes(): """ Returns: memory usage in bytes. """ if resource is not None: usage = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss if _is_darwin(): return usage return usage * 1024 else: logging.warning( 'Resource module is not available for current platform, ' 'memory usage cannot be fetched.') return 0