MLTransform (apache#26795)

* Initial work on MLTransform and ProcessHandler

* Support for containers: List, Dict[str, np.ndarray]
pass types
Support Pyarrow schema
Artifact WIP

* Add  min, max, artifacts for scale_0_to_1

* Add more transform functions and artifacts
WIP on inferring types
Remove pyarrow implementation
Add MLTransformOutput
Refactor files

* Add generic type annotations

* Add unit tests
Fix artifacts code
Add more tests
fix lint erors
Change namespaces from ml_transform to transforms
Add doc strings
Add tests and refactor

* Add support for saving intermediate results for a transform
Sort imports
Add metrics namespaces
Refactor

* Add schema to the output PCollection

* Remove MLTransformOutput and return Row instead with schema

* Convert primitive type to list using a DoFn. Remove FixedLenFeatureSpec

Make VarLenFeatureSpec as default
Refactoring

* Add append_transform to the ProcessHandler
Some more refactoring

* Remove param self.has_artifacts, add artifact_location to handler..and address PR comments
Add skip conditions for tests
Add test suite for tft tests

* Move tensorflow import into the try except catch
Try except in __init__.py
Remove imports from __init__
Add docstrings, refactor

* Add type annotations for the data transforms

* Add tft test in tox.ini

Mock tensorflow_transform in pydocs
fix tft pypi name

Skip a test
Add step name
Update  supported versions of TFT

* Add step name for TFTProcessHandler

* Remove unsupported tft versions

* Fix mypy

* Refactor TFTProcessHandlerDict to TFTProcessHandlerSchema

* Update doc for data processing transforms

* Fix checking the typing container types

* Refactor code

* Fail TFTProcessHandler on a non-global window PColl

* Remove underscore

* Remove high level functions

* Add TFIDF

* Fix tests with new changes[WIP]

* Fix tests

* Refactor class name to CamelCase and remove kwrags

* use is_default instead of isinstance

* Remove falling back to staging location for artifact location

* Add TFIDF tests

* Remove __str__

* Refactor skip statement

* Add utils for fetching artifacts on compute and apply vocab

* Make ProcessHandler internal class

* Only run analyze stage when transform_fn(artifacts) is not computed before.

* Fail if pipeline has non default window during artifact producing stage

* Add support for Dict, recordbatch and introduce artifact_mode

* Hide process_handler from user. Make TFTProcessHandler as default

* Refactor few tests

* Comment a test

* Save raw_data_meta_data so that it can be used during consume stage

* Refactor code

* Add test on artifacts

* Fix imports

* Add tensorflow_metadata to pydocs

* Fix test

* Add TFIDF to import

* Add basic example

* Remove redundant logging statements

* Add test for multiple columns on MLTransform

* Add todo about what to do when new process handler is introduced

* Add abstractmethod decorator

* Edit Error message

* Update docs, error messages

* Remove record batch input/output arg

* Modify generic types

* Fix import sort

* Fix mypy errors - best effort

* Fix tests

* Add TFTOperation doc

* Rename tft_transform  to tft

* Fix hadler_test

* Fix base_test

* Fix pydocs

sdks/python/apache_beam/examples/ml_transform/ml_transform_basic.py

@@ -0,0 +1,118 @@
+#
+# 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.
+#
+
+"""
+This example demonstrates how to use MLTransform.
+MLTransform is a PTransform that applies multiple data transformations on the
+incoming data.
+
+This example computes the vocabulary on the incoming data. Then, it computes
+the TF-IDF of the incoming data using the vocabulary computed in the previous
+step.
+
+1. ComputeAndApplyVocabulary computes the vocabulary on the incoming data and
+   overrides the incoming data with the vocabulary indices.
+2. TFIDF computes the TF-IDF of the incoming data using the vocabulary and
+    provides vocab_index and tf-idf weights. vocab_index is suffixed with
+    '_vocab_index' and tf-idf weights are suffixed with '_tfidf' to the
+    original column name(which is the output of ComputeAndApplyVocabulary).
+
+MLTransform produces artifacts, for example: ComputeAndApplyVocabulary produces
+a text file that contains vocabulary which is saved in `artifact_location`.
+ComputeAndApplyVocabulary outputs vocab indices associated with the saved vocab
+file. This mode of MLTransform is called artifact `produce` mode.
+This will be useful when the data is preprocessed before ML model training.
+
+The second mode of MLTransform is artifact `consume` mode. In this mode, the
+transformations are applied on the incoming data using the artifacts produced
+by the previous run of MLTransform. This mode will be useful when the data is
+preprocessed before ML model inference.
+"""
+
+import argparse
+import logging
+import tempfile
+
+import apache_beam as beam
+from apache_beam.ml.transforms.base import ArtifactMode
+from apache_beam.ml.transforms.base import MLTransform
+from apache_beam.ml.transforms.tft import TFIDF
+from apache_beam.ml.transforms.tft import ComputeAndApplyVocabulary
+from apache_beam.ml.transforms.utils import ArtifactsFetcher
+
+
+def parse_args():
+  parser = argparse.ArgumentParser()
+  parser.add_argument('--artifact_location', type=str, default='')
+  return parser.parse_known_args()
+
+
+def run(args):
+  data = [
+      dict(x=["Let's", "go", "to", "the", "park"]),
+      dict(x=["I", "enjoy", "going", "to", "the", "park"]),
+      dict(x=["I", "enjoy", "reading", "books"]),
+      dict(x=["Beam", "can", "be", "fun"]),
+      dict(x=["The", "weather", "is", "really", "nice", "today"]),
+      dict(x=["I", "love", "to", "go", "to", "the", "park"]),
+      dict(x=["I", "love", "to", "read", "books"]),
+      dict(x=["I", "love", "to", "program"]),
+  ]
+
+  with beam.Pipeline() as p:
+    input_data = p | beam.Create(data)
+
+    # arfifacts produce mode.
+    input_data |= (
+        'MLTransform' >> MLTransform(
+            artifact_location=args.artifact_location,
+            artifact_mode=ArtifactMode.PRODUCE,
+        ).with_transform(ComputeAndApplyVocabulary(
+            columns=['x'])).with_transform(TFIDF(columns=['x'])))
+
+    # _ =  input_data | beam.Map(logging.info)
+
+  with beam.Pipeline() as p:
+    input_data = [
+        dict(x=['I', 'love', 'books']), dict(x=['I', 'love', 'Apache', 'Beam'])
+    ]
+    input_data = p | beam.Create(input_data)
+
+    # artifacts consume mode.
+    input_data |= (
+        MLTransform(
+            artifact_location=args.artifact_location,
+            artifact_mode=ArtifactMode.CONSUME,
+            # you don't need to specify transforms as they are already saved in
+            # in the artifacts.
+        ))
+
+    _ = input_data | beam.Map(logging.info)
+
+  # To fetch the artifacts after the pipeline is run
+  artifacts_fetcher = ArtifactsFetcher(artifact_location=args.artifact_location)
+  vocab_list = artifacts_fetcher.get_vocab_list()
+  assert vocab_list[22] == 'Beam'
+
+
+if __name__ == '__main__':
+  logging.getLogger().setLevel(logging.INFO)
+  args, pipeline_args = parse_args()
+  # for this example, create a temp artifact location if not provided.
+  if args.artifact_location == '':
+    args.artifact_location = tempfile.mkdtemp()
+  run(args)

sdks/python/apache_beam/ml/transforms/__init__.py

@@ -0,0 +1,16 @@
+#
+# 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.
+#

sdks/python/apache_beam/ml/transforms/base.py

@@ -0,0 +1,165 @@
+#
+# 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.
+
+# pytype: skip-file
+
+import abc
+from typing import Generic
+from typing import List
+from typing import Optional
+from typing import Sequence
+from typing import TypeVar
+
+import apache_beam as beam
+
+__all__ = ['MLTransform', 'ProcessHandler', 'BaseOperation']
+
+TransformedDatasetT = TypeVar('TransformedDatasetT')
+TransformedMetadataT = TypeVar('TransformedMetadataT')
+
+# Input/Output types to the MLTransform.
+ExampleT = TypeVar('ExampleT')
+MLTransformOutputT = TypeVar('MLTransformOutputT')
+
+# Input to the apply() method of BaseOperation.
+OperationInputT = TypeVar('OperationInputT')
+# Output of the apply() method of BaseOperation.
+OperationOutputT = TypeVar('OperationOutputT')
+
+
+class ArtifactMode(object):
+  PRODUCE = 'produce'
+  CONSUME = 'consume'
+
+
+class BaseOperation(Generic[OperationInputT, OperationOutputT], abc.ABC):
+  def __init__(self, columns: List[str]) -> None:
+    """
+    Base Opertation class data processing transformations.
+    Args:
+      columns: List of column names to apply the transformation.
+    """
+    self.columns = columns
+
+  @abc.abstractmethod
+  def apply(
+      self, data: OperationInputT, output_column_name: str) -> OperationOutputT:
+    """
+    Define any processing logic in the apply() method.
+    processing logics are applied on inputs and returns a transformed
+    output.
+    Args:
+      inputs: input data.
+    """
+
+
+class ProcessHandler(Generic[ExampleT, MLTransformOutputT], abc.ABC):
+  """
+  Only for internal use. No backwards compatibility guarantees.
+  """
+  @abc.abstractmethod
+  def process_data(
+      self, pcoll: beam.PCollection[ExampleT]
+  ) -> beam.PCollection[MLTransformOutputT]:
+    """
+    Logic to process the data. This will be the entrypoint in
+    beam.MLTransform to process incoming data.
+    """
+
+  @abc.abstractmethod
+  def append_transform(self, transform: BaseOperation):
+    """
+    Append transforms to the ProcessHandler.
+    """
+
+
+class MLTransform(beam.PTransform[beam.PCollection[ExampleT],
+                                  beam.PCollection[MLTransformOutputT]],
+                  Generic[ExampleT, MLTransformOutputT]):
+  def __init__(
+      self,
+      *,
+      artifact_location: str,
+      artifact_mode: str = ArtifactMode.PRODUCE,
+      transforms: Optional[Sequence[BaseOperation]] = None):
+    """
+    Args:
+      artifact_location: A storage location for artifacts resulting from
+        MLTransform. These artifacts include transformations applied to
+        the dataset and generated values like min, max from ScaleTo01,
+        and mean, var from ScaleToZScore. Artifacts are produced and stored
+        in this location when the `artifact_mode` is set to 'produce'.
+        Conversely, when `artifact_mode` is set to 'consume', artifacts are
+        retrieved from this location. Note that when consuming artifacts,
+        it is not necessary to pass the transforms since they are inherently
+        stored within the artifacts themselves. The value assigned to
+        `artifact_location` should be a valid storage path where the artifacts
+        can be written to or read from.
+      transforms: A list of transforms to apply to the data. All the transforms
+        are applied in the order they are specified. The input of the
+        i-th transform is the output of the (i-1)-th transform. Multi-input
+        transforms are not supported yet.
+      artifact_mode: Whether to produce or consume artifacts. If set to
+        'consume', the handler will assume that the artifacts are already
+        computed and stored in the artifact_location. Pass the same artifact
+        location that was passed during produce phase to ensure that the
+        right artifacts are read. If set to 'produce', the handler
+        will compute the artifacts and store them in the artifact_location.
+        The artifacts will be read from this location during the consume phase.
+        There is no need to pass the transforms in this case since they are
+        already embedded in the stored artifacts.
+    """
+    # avoid circular import
+    # pylint: disable=wrong-import-order, wrong-import-position
+    from apache_beam.ml.transforms.handlers import TFTProcessHandler
+    # TODO: When new ProcessHandlers(eg: JaxProcessHandler) are introduced,
+    # create a mapping between transforms and ProcessHandler since
+    # ProcessHandler is not exposed to the user.
+    process_handler: ProcessHandler = TFTProcessHandler(
+        artifact_location=artifact_location,
+        artifact_mode=artifact_mode,
+        transforms=transforms)  # type: ignore[arg-type]
+
+    self._process_handler = process_handler
+
+  def expand(
+      self, pcoll: beam.PCollection[ExampleT]
+  ) -> beam.PCollection[MLTransformOutputT]:
+    """
+    This is the entrypoint for the MLTransform. This method will
+    invoke the process_data() method of the ProcessHandler instance
+    to process the incoming data.
+
+    process_data takes in a PCollection and applies the PTransforms
+    necessary to process the data and returns a PCollection of
+    transformed data.
+    Args:
+      pcoll: A PCollection of ExampleT type.
+    Returns:
+      A PCollection of MLTransformOutputT type.
+    """
+    return self._process_handler.process_data(pcoll)
+
+  def with_transform(self, transform: BaseOperation):
+    """
+    Add a transform to the MLTransform pipeline.
+    Args:
+      transform: A BaseOperation instance.
+    Returns:
+      A MLTransform instance.
+    """
+    self._process_handler.append_transform(transform)
+    return self