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Posted to github@beam.apache.org by GitBox <gi...@apache.org> on 2022/06/03 12:32:47 UTC

[GitHub] [beam] tvalentyn commented on a diff in pull request #17462: [BEAM-14068]Add Pytorch inference IT test and example

tvalentyn commented on code in PR #17462:
URL: https://github.com/apache/beam/pull/17462#discussion_r888834446


##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long

Review Comment:
   ```suggestion
   """A pipeline that uses RunInference API to perform image classification."""
   ```
   If you want to add more details (for example about imagenet or Image, you can continue in expanded(multiline) docstring.
   
   For example:
   ```
   The pipeline uses a pre-trained PyTorch MobileNetV2 model (link) and sample images from ImageNet dataset (link) .
   
   ```



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,
+  # normalize the images using the below values.
+  # ref: https://pytorch.org/vision/stable/models.html#
+  normalize = transforms.Normalize(
+      mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
+  transform = transforms.Compose([
+      transforms.Resize(image_size),
+      transforms.ToTensor(),
+      normalize,
+  ])
+  return transform(data)
+
+
+class PostProcessor(beam.DoFn):
+  def process(
+      self, element: Union[PredictionResult, Tuple[Any, PredictionResult]]
+  ) -> Iterable[str]:
+    filename, prediction_result = element
+    prediction = torch.argmax(prediction_result.inference, dim=0)
+    yield filename + ',' + str(prediction.item())
+
+
+def run_pipeline(options: PipelineOptions, args=None):
+  """Sets up PyTorch RunInference pipeline"""
+  # reference to the class definition of the model.
+  model_class = MobileNetV2
+  # params for model class constructor. These values will be used in
+  # RunInference API to instantiate the model object.
+  model_params = {'num_classes': 1000}  # imagenet has 1000 classes.
+  # for this example, the pretrained weights are downloaded from
+  # "https://download.pytorch.org/models/mobilenet_v2-b0353104.pth"
+  # and saved on GCS bucket gs://apache-beam-ml/models/imagenet_classification_mobilenet_v2.pt,
+  # which will be used to load the model state_dict in the RunInference API.
+  model_loader = PytorchModelLoader(
+      state_dict_path=args.model_state_dict_path,
+      model_class=model_class,
+      model_params=model_params)
+  with beam.Pipeline(options=options) as p:
+    filename_value_pair = (
+        p
+        | 'Read from csv file' >> beam.io.ReadFromText(
+            args.input, skip_header_lines=1)
+        | 'Parse and read files from the input_file' >> beam.Map(

Review Comment:
   These constant become step names; long names may not look well in the UI. From what I've seen in examples, this is usually more concise, e.g.:
   
   "ReadImageNames", "ReadImages", "PreprocessImages", etc.



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,
+  # normalize the images using the below values.
+  # ref: https://pytorch.org/vision/stable/models.html#
+  normalize = transforms.Normalize(
+      mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
+  transform = transforms.Compose([
+      transforms.Resize(image_size),
+      transforms.ToTensor(),
+      normalize,
+  ])
+  return transform(data)
+
+
+class PostProcessor(beam.DoFn):
+  def process(
+      self, element: Union[PredictionResult, Tuple[Any, PredictionResult]]
+  ) -> Iterable[str]:
+    filename, prediction_result = element
+    prediction = torch.argmax(prediction_result.inference, dim=0)
+    yield filename + ',' + str(prediction.item())
+
+
+def run_pipeline(options: PipelineOptions, args=None):
+  """Sets up PyTorch RunInference pipeline"""
+  # reference to the class definition of the model.
+  model_class = MobileNetV2
+  # params for model class constructor. These values will be used in
+  # RunInference API to instantiate the model object.
+  model_params = {'num_classes': 1000}  # imagenet has 1000 classes.
+  # for this example, the pretrained weights are downloaded from
+  # "https://download.pytorch.org/models/mobilenet_v2-b0353104.pth"
+  # and saved on GCS bucket gs://apache-beam-ml/models/imagenet_classification_mobilenet_v2.pt,
+  # which will be used to load the model state_dict in the RunInference API.
+  model_loader = PytorchModelLoader(
+      state_dict_path=args.model_state_dict_path,
+      model_class=model_class,
+      model_params=model_params)
+  with beam.Pipeline(options=options) as p:
+    filename_value_pair = (
+        p
+        | 'Read from csv file' >> beam.io.ReadFromText(
+            args.input, skip_header_lines=1)
+        | 'Parse and read files from the input_file' >> beam.Map(
+            partial(read_image, path_to_dir=args.images_dir))
+        | 'Preprocess images' >> beam.MapTuple(
+            lambda file_name, data: (file_name, preprocess_image(data))))
+    predictions = (
+        filename_value_pair
+        | 'PyTorch RunInference' >> RunInference(model_loader)
+        | 'Process output' >> beam.ParDo(PostProcessor()))
+
+    if args.output:
+      predictions | "Write output to GCS" >> beam.io.WriteToText( # pylint: disable=expression-not-assigned
+        args.output,
+        shard_name_template='',
+        append_trailing_newlines=True)
+
+
+def parse_known_args(argv):
+  """Parses args for the workflow."""
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      '--input',
+      dest='input',
+      required=True,
+      help='Path to the CSV file containing image names')

Review Comment:
   ```suggestion
         help='Path to the CSV file containing image names.')
   ```



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:

Review Comment:
   Image.Image ?



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,
+  # normalize the images using the below values.
+  # ref: https://pytorch.org/vision/stable/models.html#
+  normalize = transforms.Normalize(
+      mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
+  transform = transforms.Compose([
+      transforms.Resize(image_size),
+      transforms.ToTensor(),
+      normalize,
+  ])
+  return transform(data)
+
+
+class PostProcessor(beam.DoFn):
+  def process(
+      self, element: Union[PredictionResult, Tuple[Any, PredictionResult]]
+  ) -> Iterable[str]:
+    filename, prediction_result = element
+    prediction = torch.argmax(prediction_result.inference, dim=0)
+    yield filename + ',' + str(prediction.item())
+
+
+def run_pipeline(options: PipelineOptions, args=None):
+  """Sets up PyTorch RunInference pipeline"""
+  # reference to the class definition of the model.
+  model_class = MobileNetV2
+  # params for model class constructor. These values will be used in
+  # RunInference API to instantiate the model object.
+  model_params = {'num_classes': 1000}  # imagenet has 1000 classes.
+  # for this example, the pretrained weights are downloaded from
+  # "https://download.pytorch.org/models/mobilenet_v2-b0353104.pth"

Review Comment:
   Make this a default value for --model_state_dict_path, and move the comment there?



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:

Review Comment:
   I wonder why none of our checkers catch this.



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,
+  # normalize the images using the below values.
+  # ref: https://pytorch.org/vision/stable/models.html#
+  normalize = transforms.Normalize(
+      mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
+  transform = transforms.Compose([
+      transforms.Resize(image_size),
+      transforms.ToTensor(),
+      normalize,
+  ])
+  return transform(data)
+
+
+class PostProcessor(beam.DoFn):
+  def process(
+      self, element: Union[PredictionResult, Tuple[Any, PredictionResult]]
+  ) -> Iterable[str]:
+    filename, prediction_result = element
+    prediction = torch.argmax(prediction_result.inference, dim=0)
+    yield filename + ',' + str(prediction.item())
+
+
+def run_pipeline(options: PipelineOptions, args=None):
+  """Sets up PyTorch RunInference pipeline"""
+  # reference to the class definition of the model.
+  model_class = MobileNetV2
+  # params for model class constructor. These values will be used in
+  # RunInference API to instantiate the model object.
+  model_params = {'num_classes': 1000}  # imagenet has 1000 classes.
+  # for this example, the pretrained weights are downloaded from
+  # "https://download.pytorch.org/models/mobilenet_v2-b0353104.pth"
+  # and saved on GCS bucket gs://apache-beam-ml/models/imagenet_classification_mobilenet_v2.pt,
+  # which will be used to load the model state_dict in the RunInference API.
+  model_loader = PytorchModelLoader(
+      state_dict_path=args.model_state_dict_path,
+      model_class=model_class,
+      model_params=model_params)
+  with beam.Pipeline(options=options) as p:
+    filename_value_pair = (
+        p
+        | 'Read from csv file' >> beam.io.ReadFromText(
+            args.input, skip_header_lines=1)
+        | 'Parse and read files from the input_file' >> beam.Map(
+            partial(read_image, path_to_dir=args.images_dir))
+        | 'Preprocess images' >> beam.MapTuple(
+            lambda file_name, data: (file_name, preprocess_image(data))))
+    predictions = (
+        filename_value_pair
+        | 'PyTorch RunInference' >> RunInference(model_loader)
+        | 'Process output' >> beam.ParDo(PostProcessor()))
+
+    if args.output:
+      predictions | "Write output to GCS" >> beam.io.WriteToText( # pylint: disable=expression-not-assigned
+        args.output,
+        shard_name_template='',
+        append_trailing_newlines=True)
+
+
+def parse_known_args(argv):
+  """Parses args for the workflow."""
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      '--input',
+      dest='input',

Review Comment:
   Add a default value for the input so that it's easier for the user to get started w/ running this example?



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,
+  # normalize the images using the below values.
+  # ref: https://pytorch.org/vision/stable/models.html#
+  normalize = transforms.Normalize(
+      mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
+  transform = transforms.Compose([
+      transforms.Resize(image_size),
+      transforms.ToTensor(),
+      normalize,
+  ])
+  return transform(data)
+
+
+class PostProcessor(beam.DoFn):
+  def process(
+      self, element: Union[PredictionResult, Tuple[Any, PredictionResult]]

Review Comment:
   from looking at the code, shouldn't this hint be smth like 	`element: Tuple[str, PredictionResult]]` ?



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,

Review Comment:
   Pre-trained PyTorch models expect input images normalized with the below values (ref: ...)



##########
sdks/python/apache_beam/ml/inference/pytorch_inference_it_test.py:
##########
@@ -0,0 +1,95 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+# pylint: skip-file
+
+"""End-to-End test for Pytorch Inference"""
+
+import logging
+import os
+import unittest
+import uuid
+
+import pytest
+
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.testing.test_pipeline import TestPipeline
+
+try:
+  import torch
+  from apache_beam.examples.inference import pytorch_image_classification
+except ImportError as e:
+  torch = None
+
+_EXPECTED_OUTPUTS = {
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005001.JPEG': '681',

Review Comment:
   have you considered translating class ids into category names? In practice IDs is sufficient, but perhaps for illustration purposes this would make the example a little more approachable.



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,
+  # normalize the images using the below values.
+  # ref: https://pytorch.org/vision/stable/models.html#
+  normalize = transforms.Normalize(
+      mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
+  transform = transforms.Compose([
+      transforms.Resize(image_size),
+      transforms.ToTensor(),
+      normalize,
+  ])
+  return transform(data)
+
+
+class PostProcessor(beam.DoFn):
+  def process(
+      self, element: Union[PredictionResult, Tuple[Any, PredictionResult]]
+  ) -> Iterable[str]:
+    filename, prediction_result = element
+    prediction = torch.argmax(prediction_result.inference, dim=0)
+    yield filename + ',' + str(prediction.item())
+
+
+def run_pipeline(options: PipelineOptions, args=None):
+  """Sets up PyTorch RunInference pipeline"""
+  # reference to the class definition of the model.
+  model_class = MobileNetV2
+  # params for model class constructor. These values will be used in
+  # RunInference API to instantiate the model object.
+  model_params = {'num_classes': 1000}  # imagenet has 1000 classes.
+  # for this example, the pretrained weights are downloaded from
+  # "https://download.pytorch.org/models/mobilenet_v2-b0353104.pth"
+  # and saved on GCS bucket gs://apache-beam-ml/models/imagenet_classification_mobilenet_v2.pt,
+  # which will be used to load the model state_dict in the RunInference API.
+  model_loader = PytorchModelLoader(
+      state_dict_path=args.model_state_dict_path,
+      model_class=model_class,
+      model_params=model_params)
+  with beam.Pipeline(options=options) as p:
+    filename_value_pair = (
+        p
+        | 'Read from csv file' >> beam.io.ReadFromText(
+            args.input, skip_header_lines=1)
+        | 'Parse and read files from the input_file' >> beam.Map(
+            partial(read_image, path_to_dir=args.images_dir))
+        | 'Preprocess images' >> beam.MapTuple(
+            lambda file_name, data: (file_name, preprocess_image(data))))
+    predictions = (
+        filename_value_pair
+        | 'PyTorch RunInference' >> RunInference(model_loader)
+        | 'Process output' >> beam.ParDo(PostProcessor()))
+
+    if args.output:
+      predictions | "Write output to GCS" >> beam.io.WriteToText( # pylint: disable=expression-not-assigned
+        args.output,
+        shard_name_template='',
+        append_trailing_newlines=True)
+
+
+def parse_known_args(argv):
+  """Parses args for the workflow."""
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      '--input',
+      dest='input',
+      required=True,
+      help='Path to the CSV file containing image names')
+  parser.add_argument(
+      '--output',
+      dest='output',
+      help='Predictions are saved to the output'
+      ' text file.')
+  parser.add_argument(
+      '--model_state_dict_path',
+      dest='model_state_dict_path',
+      required=True,
+      help='Path to load the model.')

Review Comment:
   Should this be sth like: 
   ```suggestion
         help='Path to the MobileNetV2 model weights.')
   ```



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,
+  # normalize the images using the below values.
+  # ref: https://pytorch.org/vision/stable/models.html#
+  normalize = transforms.Normalize(
+      mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
+  transform = transforms.Compose([
+      transforms.Resize(image_size),
+      transforms.ToTensor(),
+      normalize,
+  ])
+  return transform(data)
+
+
+class PostProcessor(beam.DoFn):
+  def process(
+      self, element: Union[PredictionResult, Tuple[Any, PredictionResult]]
+  ) -> Iterable[str]:
+    filename, prediction_result = element
+    prediction = torch.argmax(prediction_result.inference, dim=0)
+    yield filename + ',' + str(prediction.item())
+
+
+def run_pipeline(options: PipelineOptions, args=None):
+  """Sets up PyTorch RunInference pipeline"""
+  # reference to the class definition of the model.
+  model_class = MobileNetV2
+  # params for model class constructor. These values will be used in
+  # RunInference API to instantiate the model object.
+  model_params = {'num_classes': 1000}  # imagenet has 1000 classes.
+  # for this example, the pretrained weights are downloaded from
+  # "https://download.pytorch.org/models/mobilenet_v2-b0353104.pth"
+  # and saved on GCS bucket gs://apache-beam-ml/models/imagenet_classification_mobilenet_v2.pt,
+  # which will be used to load the model state_dict in the RunInference API.
+  model_loader = PytorchModelLoader(
+      state_dict_path=args.model_state_dict_path,
+      model_class=model_class,
+      model_params=model_params)
+  with beam.Pipeline(options=options) as p:
+    filename_value_pair = (
+        p
+        | 'Read from csv file' >> beam.io.ReadFromText(
+            args.input, skip_header_lines=1)
+        | 'Parse and read files from the input_file' >> beam.Map(
+            partial(read_image, path_to_dir=args.images_dir))
+        | 'Preprocess images' >> beam.MapTuple(
+            lambda file_name, data: (file_name, preprocess_image(data))))
+    predictions = (
+        filename_value_pair
+        | 'PyTorch RunInference' >> RunInference(model_loader)
+        | 'Process output' >> beam.ParDo(PostProcessor()))
+
+    if args.output:
+      predictions | "Write output to GCS" >> beam.io.WriteToText( # pylint: disable=expression-not-assigned
+        args.output,
+        shard_name_template='',
+        append_trailing_newlines=True)
+
+
+def parse_known_args(argv):
+  """Parses args for the workflow."""
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      '--input',
+      dest='input',
+      required=True,
+      help='Path to the CSV file containing image names')
+  parser.add_argument(
+      '--output',
+      dest='output',
+      help='Predictions are saved to the output'
+      ' text file.')
+  parser.add_argument(
+      '--model_state_dict_path',
+      dest='model_state_dict_path',
+      required=True,
+      help='Path to load the model.')
+  parser.add_argument(
+      '--images_dir',
+      default=None,
+      help='Path to the directory where images are stored.'
+      'This is not required if the --input has absolute path to the images.')

Review Comment:
   ```suggestion
         'Not required if image names in the input file have absolute path.')
   ```



##########
sdks/python/apache_beam/ml/inference/pytorch_inference_it_test.py:
##########
@@ -0,0 +1,95 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+# pylint: skip-file
+
+"""End-to-End test for Pytorch Inference"""
+
+import logging
+import os
+import unittest
+import uuid
+
+import pytest
+
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.testing.test_pipeline import TestPipeline
+
+try:
+  import torch
+  from apache_beam.examples.inference import pytorch_image_classification
+except ImportError as e:
+  torch = None
+
+_EXPECTED_OUTPUTS = {
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005001.JPEG': '681',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005002.JPEG': '333',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005003.JPEG': '711',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005004.JPEG': '286',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005005.JPEG': '433',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005006.JPEG': '290',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005007.JPEG': '890',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005008.JPEG': '592',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005009.JPEG': '406',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005010.JPEG': '996',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005011.JPEG': '327',
+    'gs://apache-beam-ml/datasets/imagenet/raw-data/validation/ILSVRC2012_val_00005012.JPEG': '573'
+}
+
+
+def process_outputs(filepath):
+  with FileSystems().open(filepath) as f:
+    lines = f.readlines()
+  lines = [l.decode('utf-8').strip('\n') for l in lines]
+  return lines
+
+
+@unittest.skipIf(
+    os.getenv('FORCE_TORCH_IT') is None and torch is None,
+    'Missing dependencies. '
+    'Test depends on torch, torchvision and pillow')
+class PyTorchInference(unittest.TestCase):
+  @pytest.mark.uses_pytorch
+  @pytest.mark.it_postcommit
+  def test_torch_run_inference_imagenet_mobilenetv2(self):
+    test_pipeline = TestPipeline(is_integration_test=True)
+    # text files containing absolute path to the imagenet validation data on GCS
+    file_of_image_names = 'gs://apache-beam-ml/testing/inputs/it_mobilenetv2_imagenet_validation_inputs.txt'  # disable: line-too-long
+    output_file_dir = 'gs://apache-beam-ml/testing/predictions'
+    output_file = '/'.join([output_file_dir, str(uuid.uuid4()), 'result.txt'])
+
+    model_state_dict_path = 'gs://apache-beam-ml/models/imagenet_classification_mobilenet_v2.pt'

Review Comment:
   may be no longer necessary if already default.



##########
sdks/python/scripts/run_integration_test.sh:
##########
@@ -213,9 +218,13 @@ if [[ -z $PIPELINE_OPTS ]]; then
   # Install test dependencies for ValidatesRunner tests.
   # pyhamcrest==1.10.0 doesn't work on Py2.
   # See: https://github.com/hamcrest/PyHamcrest/issues/131.
-  echo "pyhamcrest!=1.10.0,<2.0.0" > postcommit_requirements.txt
-  echo "mock<3.0.0" >> postcommit_requirements.txt
-  echo "parameterized>=0.7.1,<0.8.0" >> postcommit_requirements.txt
+  if [[ -z $REQUIREMENTS_FILE ]]; then
+    echo "pyhamcrest!=1.10.0,<2.0.0" > requirements.txt

Review Comment:
   I would avoid using `requirements.txt` as this is a common name, and potentially can be already created by a beam developer for other reasons, then, the script could overwrite this file. 



##########
sdks/python/apache_beam/examples/inference/pytorch_image_classification.py:
##########
@@ -0,0 +1,146 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License 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.
+#
+
+"""Pipeline that uses RunInference API to perform classification task on imagenet dataset"""  # pylint: disable=line-too-long
+
+import argparse
+import io
+import os
+from functools import partial
+from typing import Any
+from typing import Iterable
+from typing import Tuple
+from typing import Union
+
+import apache_beam as beam
+import torch
+from apache_beam.io.filesystems import FileSystems
+from apache_beam.ml.inference.api import PredictionResult
+from apache_beam.ml.inference.api import RunInference
+from apache_beam.ml.inference.pytorch_inference import PytorchModelLoader
+from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.options.pipeline_options import SetupOptions
+from PIL import Image
+from torchvision import transforms
+from torchvision.models.mobilenetv2 import MobileNetV2
+
+
+def read_image(image_file_name: str,
+               path_to_dir: str = None) -> Tuple[str, Image.Image]:
+  if path_to_dir is not None:
+    image_file_name = os.path.join(path_to_dir, image_file_name)
+  with FileSystems().open(image_file_name, 'r') as file:
+    data = Image.open(io.BytesIO(file.read())).convert('RGB')
+    return image_file_name, data
+
+
+def preprocess_image(data: Image) -> torch.Tensor:
+  image_size = (224, 224)
+  # to use models in torch with imagenet weights,
+  # normalize the images using the below values.
+  # ref: https://pytorch.org/vision/stable/models.html#
+  normalize = transforms.Normalize(
+      mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
+  transform = transforms.Compose([
+      transforms.Resize(image_size),
+      transforms.ToTensor(),
+      normalize,
+  ])
+  return transform(data)
+
+
+class PostProcessor(beam.DoFn):
+  def process(
+      self, element: Union[PredictionResult, Tuple[Any, PredictionResult]]
+  ) -> Iterable[str]:
+    filename, prediction_result = element
+    prediction = torch.argmax(prediction_result.inference, dim=0)
+    yield filename + ',' + str(prediction.item())
+
+
+def run_pipeline(options: PipelineOptions, args=None):
+  """Sets up PyTorch RunInference pipeline"""
+  # reference to the class definition of the model.
+  model_class = MobileNetV2
+  # params for model class constructor. These values will be used in
+  # RunInference API to instantiate the model object.
+  model_params = {'num_classes': 1000}  # imagenet has 1000 classes.
+  # for this example, the pretrained weights are downloaded from
+  # "https://download.pytorch.org/models/mobilenet_v2-b0353104.pth"
+  # and saved on GCS bucket gs://apache-beam-ml/models/imagenet_classification_mobilenet_v2.pt,
+  # which will be used to load the model state_dict in the RunInference API.
+  model_loader = PytorchModelLoader(
+      state_dict_path=args.model_state_dict_path,
+      model_class=model_class,
+      model_params=model_params)
+  with beam.Pipeline(options=options) as p:
+    filename_value_pair = (
+        p
+        | 'Read from csv file' >> beam.io.ReadFromText(
+            args.input, skip_header_lines=1)
+        | 'Parse and read files from the input_file' >> beam.Map(
+            partial(read_image, path_to_dir=args.images_dir))
+        | 'Preprocess images' >> beam.MapTuple(
+            lambda file_name, data: (file_name, preprocess_image(data))))
+    predictions = (
+        filename_value_pair
+        | 'PyTorch RunInference' >> RunInference(model_loader)
+        | 'Process output' >> beam.ParDo(PostProcessor()))
+
+    if args.output:
+      predictions | "Write output to GCS" >> beam.io.WriteToText( # pylint: disable=expression-not-assigned
+        args.output,
+        shard_name_template='',
+        append_trailing_newlines=True)
+
+
+def parse_known_args(argv):
+  """Parses args for the workflow."""
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      '--input',
+      dest='input',
+      required=True,
+      help='Path to the CSV file containing image names')
+  parser.add_argument(
+      '--output',
+      dest='output',
+      help='Predictions are saved to the output'
+      ' text file.')
+  parser.add_argument(
+      '--model_state_dict_path',
+      dest='model_state_dict_path',
+      required=True,
+      help='Path to load the model.')

Review Comment:
   optionally, we could add model class as  a parameter later. Although, perhaps such customization would be better suited for a flex template. 



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