estimator.py

# Copyright 2017-2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"). You
# may not use this file except in compliance with the License. A copy of
# the License is located at
#
#     http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file is
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
# ANY KIND, either express or implied. See the License for the specific
# language governing permissions and limitations under the License.
"""Placeholder docstring"""
from __future__ import absolute_import

import contextlib
import logging
import os
import shutil
import subprocess
import tempfile
import threading
import time

from sagemaker.debugger import DebuggerHookConfig
from sagemaker.estimator import Framework
import sagemaker.fw_utils as fw
from sagemaker.tensorflow import defaults
from sagemaker.tensorflow.model import TensorFlowModel
from sagemaker.tensorflow.serving import Model
from sagemaker.transformer import Transformer
from sagemaker import utils
from sagemaker.vpc_utils import VPC_CONFIG_DEFAULT

logger = logging.getLogger("sagemaker")


_FRAMEWORK_MODE_ARGS = (
    "training_steps",
    "evaluation_steps",
    "requirements_file",
    "checkpoint_path",
)
_SCRIPT_MODE = "tensorflow-scriptmode"
_SCRIPT_MODE_SERVING_ERROR_MSG = (
    "Script mode containers does not support serving yet. "
    "Please use our new tensorflow-serving container by creating the model "
    "with 'endpoint_type' set to 'tensorflow-serving'."
)
_SCRIPT_MODE_TENSORBOARD_WARNING = (
    "Tensorboard is not supported with script mode. You can run the following "
    "command: tensorboard --logdir %s --host localhost --port 6006 This can be "
    "run from anywhere with access to the S3 URI used as the logdir."
)


class Tensorboard(threading.Thread):
    """Placeholder docstring"""

    def __init__(self, estimator, logdir=None):
        """Initialize ``Tensorboard`` instance.

        Args:
            estimator (sagemaker.estimator.Framework): A SageMaker ``Estimator``.
            logdir (str): Directory for logs (default: None). If not specified, a temporary
                directory is made.
        """
        threading.Thread.__init__(self)
        self.event = threading.Event()
        self.estimator = estimator
        self.logdir = logdir or tempfile.mkdtemp()

    @staticmethod
    def _cmd_exists(cmd):
        """Placeholder docstring"""
        return any(
            os.access(os.path.join(path, cmd), os.X_OK)
            for path in os.environ["PATH"].split(os.pathsep)
        )

    @staticmethod
    def _sync_directories(from_directory, to_directory):
        """Sync to_directory with from_directory by copying each file in
        to_directory with new contents. Files in to_directory will be
        overwritten by files of the same name in from_directory. We need to
        keep two copies of the log directory because otherwise TensorBoard
        picks up temp files from `aws s3 sync` and then stops reading the
        correct tfevent files. We walk the directory and copy each file
        individually because the directory that TensorBoard watches needs to
        always exist.

        Args:
            from_directory (str): The directory with updated files.
            to_directory (str): The directory to be synced.
        """
        if not os.path.exists(to_directory):
            os.mkdir(to_directory)
        for root, dirs, files in os.walk(from_directory):
            to_root = root.replace(from_directory, to_directory)
            for directory in dirs:
                to_child_dir = os.path.join(to_root, directory)
                if not os.path.exists(to_child_dir):
                    os.mkdir(to_child_dir)
            for fname in files:
                from_file = os.path.join(root, fname)
                to_file = os.path.join(to_root, fname)
                with open(from_file, "rb") as a, open(to_file, "wb") as b:
                    b.write(a.read())

    @staticmethod
    @contextlib.contextmanager
    def _temporary_directory():
        """Context manager for a temporary directory. This is similar to
        tempfile.TemporaryDirectory in python>=3.2.
        """
        name = tempfile.mkdtemp()
        try:
            yield name
        finally:
            shutil.rmtree(name)

    def validate_requirements(self):
        """Ensure that TensorBoard and the AWS CLI are installed.

        These dependencies are required for using TensorBoard.

        Raises:
            EnvironmentError: If at least one requirement is not installed.
        """
        if not self._cmd_exists("tensorboard"):
            raise EnvironmentError(
                "TensorBoard is not installed in the system. Please install TensorBoard using the"
                " following command: \n pip install tensorboard"
            )

        if not self._cmd_exists("aws"):
            raise EnvironmentError(
                "The AWS CLI is not installed in the system. Please install the AWS CLI using the"
                " following command: \n pip install awscli"
            )

    def create_tensorboard_process(self):
        """Create a TensorBoard process.

        Returns:
            tuple: A tuple containing:
                int: The port number.
                process: The TensorBoard process.

        Raises:
            OSError: If no ports between 6006 and 6105 are available for starting TensorBoard.
        """
        port = 6006

        for _ in range(100):
            p = subprocess.Popen(
                [
                    "tensorboard",
                    "--logdir",
                    self.logdir,
                    "--host",
                    "localhost",
                    "--port",
                    str(port),
                ],
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
            )
            self.event.wait(5)
            if p.poll():
                port += 1
            else:
                return port, p

        raise OSError(
            "No available ports to start TensorBoard. Attempted all ports between 6006 and 6105"
        )

    def run(self):
        """Run TensorBoard process."""
        port, tensorboard_process = self.create_tensorboard_process()

        logger.info("TensorBoard 0.1.7 at http://localhost:%s", port)
        while not self.estimator.checkpoint_path:
            self.event.wait(1)
        with self._temporary_directory() as aws_sync_dir:
            while not self.event.is_set():
                args = ["aws", "s3", "sync", self.estimator.checkpoint_path, aws_sync_dir]
                subprocess.call(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
                self._sync_directories(aws_sync_dir, self.logdir)
                self.event.wait(10)
        tensorboard_process.terminate()


class TensorFlow(Framework):
    """Handle end-to-end training and deployment of user-provided TensorFlow code."""

    __framework_name__ = "tensorflow"

    LATEST_VERSION = defaults.LATEST_VERSION

    _LATEST_1X_VERSION = "1.15.2"

    _LOWEST_SCRIPT_MODE_ONLY_VERSION = [1, 13]
    # 2.0.0 still supports py2
    # we will need to update this version number if future versions still support py2
    _HIGHEST_PYTHON_2_VERSION = [2, 1, 0]

    def __init__(
        self,
        training_steps=None,
        evaluation_steps=None,
        checkpoint_path=None,
        py_version=None,
        framework_version=None,
        model_dir=None,
        requirements_file="",
        image_name=None,
        script_mode=False,
        distributions=None,
        **kwargs
    ):
        """Initialize a ``TensorFlow`` estimator.

        Args:
            training_steps (int): Perform this many steps of training. `None`, the default means
                train forever.
            evaluation_steps (int): Perform this many steps of evaluation. `None`, the default
                means that evaluation runs until input from eval_input_fn is exhausted (or another
                exception is raised).
            checkpoint_path (str): Identifies S3 location where checkpoint data during model
                training can be saved (default: None). For distributed model training, this
                parameter is required.
            py_version (str): Python version you want to use for executing your model training
                code (default: 'py2').
            framework_version (str): TensorFlow version you want to use for executing your model
                training code. List of supported versions
                https://github.com/aws/sagemaker-python-sdk#tensorflow-sagemaker-estimators.
                If not specified, this will default to 1.11.
            model_dir (str): S3 location where the checkpoint data and models can be exported to
                during training (default: None). If not specified a default S3 URI will be
                generated. It will be passed in the training script as one of the command line
                arguments.
            requirements_file (str): Path to a ``requirements.txt`` file (default: ''). The path
                should be within and relative to ``source_dir``. Details on the format can be
                found in the Pip User Guide:
                <https://pip.pypa.io/en/stable/reference/pip_install/#requirements-file-format>
            image_name (str): If specified, the estimator will use this image for training and
                hosting, instead of selecting the appropriate SageMaker official image based on
                framework_version and py_version. It can be an ECR url or dockerhub image and tag.

                Examples:
                    123.dkr.ecr.us-west-2.amazonaws.com/my-custom-image:1.0
                    custom-image:latest.
            script_mode (bool): If set to True will the estimator will use the Script Mode
                containers (default: False). This will be ignored if py_version is set to 'py3'.
            distributions (dict): A dictionary with information on how to run distributed training
                (default: None). Currently we support distributed training with parameter servers
                and MPI.
                To enable parameter server use the following setup:

                .. code:: python

                    {
                        'parameter_server':
                        {
                            'enabled': True
                        }
                    }

                To enable MPI:

                .. code:: python

                    {
                        'mpi':
                        {
                            'enabled': True
                        }
                    }

            **kwargs: Additional kwargs passed to the Framework constructor.

        .. tip::

            You can find additional parameters for initializing this class at
            :class:`~sagemaker.estimator.Framework` and
            :class:`~sagemaker.estimator.EstimatorBase`.
        """
        if framework_version is None:
            logger.warning(
                fw.empty_framework_version_warning(defaults.TF_VERSION, self.LATEST_VERSION)
            )
        self.framework_version = framework_version or defaults.TF_VERSION

        if not py_version:
            py_version = "py3" if self._only_python_3_supported() else "py2"
        if py_version == "py2":
            logger.warning(
                fw.python_deprecation_warning(self.__framework_name__, defaults.LATEST_PY2_VERSION)
            )

        if "enable_sagemaker_metrics" not in kwargs:
            # enable sagemaker metrics for TF v1.15 or greater:
            if fw.is_version_equal_or_higher([1, 15], self.framework_version):
                kwargs["enable_sagemaker_metrics"] = True

        super(TensorFlow, self).__init__(image_name=image_name, **kwargs)
        self.checkpoint_path = checkpoint_path

        self.py_version = py_version
        self.training_steps = training_steps
        self.evaluation_steps = evaluation_steps
        self.model_dir = model_dir
        self.script_mode = script_mode
        self.distributions = distributions or {}

        self._validate_args(
            py_version=py_version,
            script_mode=script_mode,
            framework_version=self.framework_version,
            training_steps=training_steps,
            evaluation_steps=evaluation_steps,
            requirements_file=requirements_file,
            checkpoint_path=checkpoint_path,
        )
        self._validate_requirements_file(requirements_file)
        self.requirements_file = requirements_file

    def _validate_args(
        self,
        py_version,
        script_mode,
        framework_version,
        training_steps,
        evaluation_steps,
        requirements_file,
        checkpoint_path,
    ):
        """Placeholder docstring"""

        if py_version == "py3" or script_mode:

            if framework_version is None:
                raise AttributeError(fw.EMPTY_FRAMEWORK_VERSION_ERROR)

            found_args = []
            if training_steps:
                found_args.append("training_steps")
            if evaluation_steps:
                found_args.append("evaluation_steps")
            if requirements_file:
                found_args.append("requirements_file")
            if checkpoint_path:
                found_args.append("checkpoint_path")
            if found_args:
                raise AttributeError(
                    "{} are deprecated in script mode. Please do not set {}.".format(
                        ", ".join(_FRAMEWORK_MODE_ARGS), ", ".join(found_args)
                    )
                )

        if py_version == "py2" and self._only_python_3_supported():
            msg = (
                "Python 2 containers are only available with {} and lower versions. "
                "Please use a Python 3 container.".format(defaults.LATEST_PY2_VERSION)
            )
            raise AttributeError(msg)

        if (not self._script_mode_enabled()) and self._only_script_mode_supported():
            logger.warning(
                "Legacy mode is deprecated in versions 1.13 and higher. Using script mode instead."
            )
            self.script_mode = True

    def _only_script_mode_supported(self):
        """Placeholder docstring"""
        return [
            int(s) for s in self.framework_version.split(".")
        ] >= self._LOWEST_SCRIPT_MODE_ONLY_VERSION

    def _only_python_3_supported(self):
        """Placeholder docstring"""
        return [int(s) for s in self.framework_version.split(".")] > self._HIGHEST_PYTHON_2_VERSION

    def _validate_requirements_file(self, requirements_file):
        """Placeholder docstring"""
        if not requirements_file:
            return

        if not self.source_dir:
            raise ValueError("Must specify source_dir along with a requirements file.")

        if self.source_dir.lower().startswith("s3://"):
            return

        if os.path.isabs(requirements_file):
            raise ValueError(
                "Requirements file {} is not a path relative to source_dir.".format(
                    requirements_file
                )
            )

        if not os.path.exists(os.path.join(self.source_dir, requirements_file)):
            raise ValueError("Requirements file {} does not exist.".format(requirements_file))

    def fit(
        self,
        inputs=None,
        wait=True,
        logs=True,
        job_name=None,
        experiment_config=None,
        run_tensorboard_locally=False,
    ):
        """Train a model using the input training dataset.

        See :func:`~sagemaker.estimator.EstimatorBase.fit` for more details.

        Args:
            inputs (str or dict or sagemaker.session.s3_input): Information about the training data.
                This can be one of three types:

                * (str) - the S3 location where training data is saved.
                * (dict[str, str] or dict[str, sagemaker.session.s3_input]) - If using multiple
                    channels for training data, you can specify a dict mapping channel names
                    to strings or :func:`~sagemaker.session.s3_input` objects.
                * (sagemaker.session.s3_input) - channel configuration for S3 data sources that
                    can provide additional information as well as the path to the training dataset.
                    See :func:`sagemaker.session.s3_input` for full details.

            wait (bool): Whether the call should wait until the job completes (default: True).
            logs (bool): Whether to show the logs produced by the job.
                Only meaningful when wait is True (default: True).
            job_name (str): Training job name. If not specified, the estimator generates a default
                job name, based on the training image name and current timestamp.
            experiment_config (dict[str, str]): Experiment management configuration.
            run_tensorboard_locally (bool): Whether to execute TensorBoard in a different process
                with downloaded checkpoint information (default: False). This is an experimental
                feature, and requires TensorBoard and AWS CLI to be installed. It terminates
                TensorBoard when execution ends.
        """

        def fit_super():
            super(TensorFlow, self).fit(inputs, wait, logs, job_name, experiment_config)

        if run_tensorboard_locally and wait is False:
            raise ValueError("Tensorboard is not supported with async fit")

        if self._script_mode_enabled() and run_tensorboard_locally:
            logger.warning(_SCRIPT_MODE_TENSORBOARD_WARNING, self.model_dir)
            fit_super()
        elif run_tensorboard_locally:
            tensorboard = Tensorboard(self)
            tensorboard.validate_requirements()

            try:
                tensorboard.start()
                fit_super()
            finally:
                # sleep 20 secs for tensorboard start up if fit() quits instantly
                time.sleep(20)
                tensorboard.event.set()
                tensorboard.join()
        else:
            fit_super()

    @classmethod
    def _prepare_init_params_from_job_description(cls, job_details, model_channel_name=None):
        """Convert the job description to init params that can be handled by the class constructor

        Args:
            job_details: the returned job details from a describe_training_job API call.

        Returns:
             dictionary: The transformed init_params

        """
        init_params = super(TensorFlow, cls)._prepare_init_params_from_job_description(
            job_details, model_channel_name
        )

        # Move some of the tensorflow specific init params from hyperparameters into the main init
        # params.
        for argument in ("checkpoint_path", "training_steps", "evaluation_steps", "model_dir"):
            value = init_params["hyperparameters"].pop(argument, None)
            if value is not None:
                init_params[argument] = value

        image_name = init_params.pop("image")
        framework, py_version, tag, script_mode = fw.framework_name_from_image(image_name)
        if not framework:
            # If we were unable to parse the framework name from the image it is not one of our
            # officially supported images, in this case just add the image to the init params.
            init_params["image_name"] = image_name
            return init_params

        if script_mode:
            init_params["script_mode"] = True

        init_params["py_version"] = py_version

        # We switched image tagging scheme from regular image version (e.g. '1.0') to more
        # expressive containing framework version, device type and python version
        # (e.g. '1.5-gpu-py2'). For backward compatibility map deprecated image tag '1.0' to a
        # '1.4' framework version otherwise extract framework version from the tag itself.
        init_params["framework_version"] = (
            "1.4" if tag == "1.0" else fw.framework_version_from_tag(tag)
        )

        training_job_name = init_params["base_job_name"]
        if framework != cls.__framework_name__:
            raise ValueError(
                "Training job: {} didn't use image for requested framework".format(
                    training_job_name
                )
            )

        return init_params

    def create_model(
        self,
        model_server_workers=None,
        role=None,
        vpc_config_override=VPC_CONFIG_DEFAULT,
        endpoint_type=None,
        entry_point=None,
        source_dir=None,
        dependencies=None,
        **kwargs
    ):
        """Create a ``Model`` object that can be used for creating SageMaker model entities,
        deploying to a SageMaker endpoint, or starting SageMaker Batch Transform jobs.

        Args:
            role (str): The ``ExecutionRoleArn`` IAM Role ARN for the ``Model``, which is also
                used during transform jobs. If not specified, the role from the Estimator will be
                used.
            model_server_workers (int): Optional. The number of worker processes used by the
                inference server. If None, server will use one worker per vCPU.
            vpc_config_override (dict[str, list[str]]): Optional override for VpcConfig set on the
                model.
                Default: use subnets and security groups from this Estimator.
                * 'Subnets' (list[str]): List of subnet ids.
                * 'SecurityGroupIds' (list[str]): List of security group ids.
            endpoint_type (str): Optional. Selects the software stack used by the inference server.
                If  not specified, the model will be configured to use the default
                SageMaker model server. If 'tensorflow-serving', the model will be configured to
                use the SageMaker Tensorflow Serving container.
            entry_point (str): Path (absolute or relative) to the local Python source file which
                should be executed as the entry point to training. If not specified and
                ``endpoint_type`` is 'tensorflow-serving', no entry point is used. If
                ``endpoint_type`` is also ``None``, then the training entry point is used.
            source_dir (str): Path (absolute or relative) to a directory with any other serving
                source code dependencies aside from the entry point file. If not specified and
                ``endpoint_type`` is 'tensorflow-serving', no source_dir is used. If
                ``endpoint_type`` is also ``None``, then the model source directory from training
                is used.
            dependencies (list[str]): A list of paths to directories (absolute or relative) with
                any additional libraries that will be exported to the container.
                If not specified and ``endpoint_type`` is 'tensorflow-serving', ``dependencies`` is
                set to ``None``.
                If ``endpoint_type`` is also ``None``, then the dependencies from training are used.
            **kwargs: Additional kwargs passed to :class:`~sagemaker.tensorflow.serving.Model`
                and :class:`~sagemaker.tensorflow.model.TensorFlowModel` constructors.

        Returns:
            sagemaker.tensorflow.model.TensorFlowModel or sagemaker.tensorflow.serving.Model: A
                ``Model`` object. See :class:`~sagemaker.tensorflow.serving.Model` or
                :class:`~sagemaker.tensorflow.model.TensorFlowModel` for full details.
        """
        role = role or self.role

        if endpoint_type == "tensorflow-serving" or self._script_mode_enabled():
            return self._create_tfs_model(
                role=role,
                vpc_config_override=vpc_config_override,
                entry_point=entry_point,
                source_dir=source_dir,
                dependencies=dependencies,
                **kwargs
            )

        return self._create_default_model(
            model_server_workers=model_server_workers,
            role=role,
            vpc_config_override=vpc_config_override,
            entry_point=entry_point,
            source_dir=source_dir,
            dependencies=dependencies,
            **kwargs
        )

    def _create_tfs_model(
        self,
        role=None,
        vpc_config_override=VPC_CONFIG_DEFAULT,
        entry_point=None,
        source_dir=None,
        dependencies=None,
        **kwargs
    ):
        """Placeholder docstring"""
        return Model(
            model_data=self.model_data,
            role=role,
            image=self.image_name,
            name=self._current_job_name,
            container_log_level=self.container_log_level,
            framework_version=utils.get_short_version(self.framework_version),
            sagemaker_session=self.sagemaker_session,
            vpc_config=self.get_vpc_config(vpc_config_override),
            entry_point=entry_point,
            source_dir=source_dir,
            dependencies=dependencies,
            enable_network_isolation=self.enable_network_isolation(),
            **kwargs
        )

    def _create_default_model(
        self,
        model_server_workers,
        role,
        vpc_config_override,
        entry_point=None,
        source_dir=None,
        dependencies=None,
        **kwargs
    ):
        """Placeholder docstring"""
        return TensorFlowModel(
            self.model_data,
            role,
            entry_point or self.entry_point,
            source_dir=source_dir or self._model_source_dir(),
            enable_cloudwatch_metrics=self.enable_cloudwatch_metrics,
            env={"SAGEMAKER_REQUIREMENTS": self.requirements_file},
            image=self.image_name,
            name=self._current_job_name,
            container_log_level=self.container_log_level,
            code_location=self.code_location,
            py_version=self.py_version,
            framework_version=self.framework_version,
            model_server_workers=model_server_workers,
            sagemaker_session=self.sagemaker_session,
            vpc_config=self.get_vpc_config(vpc_config_override),
            dependencies=dependencies or self.dependencies,
            enable_network_isolation=self.enable_network_isolation(),
            **kwargs
        )

    def hyperparameters(self):
        """Return hyperparameters used by your custom TensorFlow code during model training."""
        hyperparameters = super(TensorFlow, self).hyperparameters()

        self.checkpoint_path = self.checkpoint_path or self._default_s3_path("checkpoints")
        mpi_enabled = False

        if self._script_mode_enabled():
            additional_hyperparameters = {}

            if "parameter_server" in self.distributions:
                ps_enabled = self.distributions["parameter_server"].get("enabled", False)
                additional_hyperparameters[self.LAUNCH_PS_ENV_NAME] = ps_enabled

            if "mpi" in self.distributions:
                mpi_dict = self.distributions["mpi"]
                mpi_enabled = mpi_dict.get("enabled", False)
                additional_hyperparameters[self.LAUNCH_MPI_ENV_NAME] = mpi_enabled

                if mpi_dict.get("processes_per_host"):
                    additional_hyperparameters[self.MPI_NUM_PROCESSES_PER_HOST] = mpi_dict.get(
                        "processes_per_host"
                    )

                additional_hyperparameters[self.MPI_CUSTOM_MPI_OPTIONS] = mpi_dict.get(
                    "custom_mpi_options", ""
                )

            self.model_dir = self.model_dir or self._default_s3_path("model", mpi=mpi_enabled)
            additional_hyperparameters["model_dir"] = self.model_dir
        else:
            additional_hyperparameters = {
                "checkpoint_path": self.checkpoint_path,
                "training_steps": self.training_steps,
                "evaluation_steps": self.evaluation_steps,
                "sagemaker_requirements": self.requirements_file,
            }

        hyperparameters.update(Framework._json_encode_hyperparameters(additional_hyperparameters))
        return hyperparameters

    def _default_s3_path(self, directory, mpi=False):
        """Placeholder docstring"""
        local_code = utils.get_config_value("local.local_code", self.sagemaker_session.config)
        if self.sagemaker_session.local_mode and local_code:
            return "/opt/ml/shared/{}".format(directory)
        if mpi:
            return "/opt/ml/model"
        if self._current_job_name:
            return os.path.join(self.output_path, self._current_job_name, directory)
        return None

    def _script_mode_enabled(self):
        """Placeholder docstring"""
        return self.py_version == "py3" or self.script_mode

    def _validate_and_set_debugger_configs(self):
        """
        Disable Debugger Hook Config for ParameterServer (PS) as it is not
        supported in smdebug.

        Else, set default HookConfig
        """
        ps_enabled = "parameter_server" in self.distributions and self.distributions[
            "parameter_server"
        ].get("enabled", False)
        if ps_enabled:
            if self.debugger_hook_config is not None or self.debugger_rule_configs is not None:
                logger.info(
                    "Amazon SageMaker Debugger does not currently support "
                    "Parameter Server distribution"
                )
            self.debugger_hook_config = None
            self.debugger_rule_configs = None
        elif self.debugger_hook_config is None and fw._region_supports_debugger(
            self.sagemaker_session.boto_session.region_name
        ):
            # Set defaults for debugging.
            self.debugger_hook_config = DebuggerHookConfig(s3_output_path=self.output_path)

    def train_image(self):
        """Placeholder docstring"""
        if self.image_name:
            return self.image_name

        if self._script_mode_enabled():
            return fw.create_image_uri(
                self.sagemaker_session.boto_region_name,
                _SCRIPT_MODE,
                self.train_instance_type,
                self.framework_version,
                self.py_version,
            )

        return super(TensorFlow, self).train_image()

    def transformer(
        self,
        instance_count,
        instance_type,
        strategy=None,
        assemble_with=None,
        output_path=None,
        output_kms_key=None,
        accept=None,
        env=None,
        max_concurrent_transforms=None,
        max_payload=None,
        tags=None,
        role=None,
        model_server_workers=None,
        volume_kms_key=None,
        endpoint_type=None,
        entry_point=None,
        vpc_config_override=VPC_CONFIG_DEFAULT,
    ):
        """Return a ``Transformer`` that uses a SageMaker Model based on the training job. It
        reuses the SageMaker Session and base job name used by the Estimator.

        Args:
            instance_count (int): Number of EC2 instances to use.
            instance_type (str): Type of EC2 instance to use, for example, 'ml.c4.xlarge'.
            strategy (str): The strategy used to decide how to batch records in a single request
                (default: None). Valid values: 'MULTI_RECORD' and 'SINGLE_RECORD'.
            assemble_with (str): How the output is assembled (default: None). Valid values: 'Line'
                or 'None'.
            output_path (str): S3 location for saving the transform result. If not specified,
                results are stored to a default bucket.
            output_kms_key (str): Optional. KMS key ID for encrypting the transform output
                (default: None).
            accept (str): The accept header passed by the client to
                the inference endpoint. If it is supported by the endpoint,
                it will be the format of the batch transform output.
            env (dict): Environment variables to be set for use during the transform job
                (default: None).
            max_concurrent_transforms (int): The maximum number of HTTP requests to be made to
                each individual transform container at one time.
            max_payload (int): Maximum size of the payload in a single HTTP request to the
                container in MB.
            tags (list[dict]): List of tags for labeling a transform job. If none specified, then
                the tags used for the training job are used for the transform job.
            role (str): The ``ExecutionRoleArn`` IAM Role ARN for the ``Model``, which is also
                used during transform jobs. If not specified, the role from the Estimator will be
                used.
            model_server_workers (int): Optional. The number of worker processes used by the
                inference server. If None, server will use one worker per vCPU.
            volume_kms_key (str): Optional. KMS key ID for encrypting the volume attached to the ML
                compute instance (default: None).
            endpoint_type (str): Optional. Selects the software stack used by the inference server.
                If not specified, the model will be configured to use the default
                SageMaker model server.
                If 'tensorflow-serving', the model will be configured to
                use the SageMaker Tensorflow Serving container.
            entry_point (str): Path (absolute or relative) to the local Python source file which
                should be executed as the entry point to training. If not specified and
                ``endpoint_type`` is 'tensorflow-serving', no entry point is used. If
                ``endpoint_type`` is also ``None``, then the training entry point is used.
            vpc_config_override (dict[str, list[str]]): Optional override for
                the VpcConfig set on the model.
                Default: use subnets and security groups from this Estimator.
                * 'Subnets' (list[str]): List of subnet ids.
                * 'SecurityGroupIds' (list[str]): List of security group ids.
        """
        role = role or self.role

        if self.latest_training_job is None:
            logging.warning(
                "No finished training job found associated with this estimator. Please make sure "
                "this estimator is only used for building workflow config"
            )
            return Transformer(
                self._current_job_name,
                instance_count,
                instance_type,
                strategy=strategy,
                assemble_with=assemble_with,
                output_path=output_path,
                output_kms_key=output_kms_key,
                accept=accept,
                max_concurrent_transforms=max_concurrent_transforms,
                max_payload=max_payload,
                env=env or {},
                tags=tags,
                base_transform_job_name=self.base_job_name,
                volume_kms_key=volume_kms_key,
                sagemaker_session=self.sagemaker_session,
            )

        model = self.create_model(
            model_server_workers=model_server_workers,
            role=role,
            vpc_config_override=vpc_config_override,
            endpoint_type=endpoint_type,
            entry_point=entry_point,
        )
        return model.transformer(
            instance_count,
            instance_type,
            strategy=strategy,
            assemble_with=assemble_with,
            output_path=output_path,
            output_kms_key=output_kms_key,
            accept=accept,
            env=env,
            max_concurrent_transforms=max_concurrent_transforms,
            max_payload=max_payload,
            tags=tags,
            volume_kms_key=volume_kms_key,
        )