Simplify ReadFromCroissant by removing the pipeline argument and ma…

…king it a PCollection. (#780)

…

python/mlcroissant/mlcroissant/_src/beam.py

@@ -3,46 +3,22 @@
 from __future__ import annotations
 
 from collections.abc import Mapping
-import functools
-import typing
-from typing import Any, Callable
+from typing import Any
 
 from etils import epath
 
 from mlcroissant._src.datasets import Dataset
 from mlcroissant._src.datasets import Filters
 
-if typing.TYPE_CHECKING:
-    import apache_beam as beam
-
-
-def _beam_ptransform_fn(fn: Callable[..., Any]) -> Callable[..., Any]:
-    """Lazy version of `@beam.ptransform_fn` in case Beam is not installed."""
-    lazy_decorated_fn = None
-
-    @functools.wraps(fn)
-    def decorated(*args, **kwargs):
-        nonlocal lazy_decorated_fn
-        # Actually decorate the function only the first time it is called
-        if lazy_decorated_fn is None:
-            import apache_beam as beam
-
-            lazy_decorated_fn = beam.ptransform_fn(fn)
-        return lazy_decorated_fn(*args, **kwargs)
-
-    return decorated
-
 
-@_beam_ptransform_fn
 def ReadFromCroissant(
-    pipeline: beam.Pipeline,
     *,
     jsonld: epath.PathLike | Mapping[str, Any],
     record_set: str,
     mapping: Mapping[str, epath.PathLike] | None = None,
     filters: Filters | None = None,
 ):
-    """Returns an Apache Beam reader to generate the dataset using e.g. Spark.
+    """Returns an Apache Beam PCollection to generate the dataset using e.g. Spark.
 
     Example of usage:
 
@@ -65,7 +41,6 @@ def ReadFromCroissant(
     Face datasets, so it raises an error if the dataset is not a Hugging Face dataset.
 
     Args:
-        pipeline: A Beam pipeline (automatically set).
         jsonld: A JSON object or a path to a Croissant file (URL, str or pathlib.Path).
         record_set: The name of the record set to generate.
         mapping: Mapping filename->filepath as a Python dict[str, str] to handle manual
@@ -85,7 +60,4 @@ def ReadFromCroissant(
         A ValueError if the dataset is not streamable.
     """
     dataset = Dataset(jsonld=jsonld, mapping=mapping)
-    return dataset.records(record_set, filters=filters).beam_reader(
-        pipeline,
-        filters=filters,
-    )
+    return dataset.records(record_set, filters=filters).beam_reader()

python/mlcroissant/mlcroissant/_src/datasets.py

@@ -4,7 +4,6 @@
 
 from collections.abc import Mapping
 import dataclasses
-import typing
 from typing import Any
 
 from absl import logging
@@ -29,9 +28,6 @@
 from mlcroissant._src.structure_graph.nodes.metadata import Metadata
 from mlcroissant._src.structure_graph.nodes.source import FileProperty
 
-if typing.TYPE_CHECKING:
-    import apache_beam as beam
-
 Filters = Mapping[str, Any]
 
 
@@ -176,17 +172,14 @@ def __iter__(self):
                 record_set=self.record_set, operations=operations
             )
 
-    def beam_reader(
-        self, pipeline: beam.Pipeline, filters: Mapping[str, Any] | None = None
-    ):
+    def beam_reader(self):
         """See ReadFromCroissant docstring."""
         operations = self._filter_interesting_operations(self.filters)
         execute_downloads(operations)
         return execute_operations_in_beam(
-            pipeline=pipeline,
             record_set=self.record_set,
             operations=operations,
-            filters=filters or self.filters,
+            filters=self.filters,
         )
 
     def _filter_interesting_operations(self, filters: Filters | None) -> Operations:

python/mlcroissant/mlcroissant/_src/operation_graph/execute.py

@@ -7,7 +7,6 @@
 import functools
 import json
 import sys
-import typing
 from typing import Any, Generator
 
 from absl import logging
@@ -21,9 +20,6 @@
 from mlcroissant._src.operation_graph.operations.download import Download
 from mlcroissant._src.operation_graph.operations.read import Read
 
-if typing.TYPE_CHECKING:
-    import apache_beam as beam
-
 ElementWithIndex = tuple[int, Any]
 
 
@@ -129,7 +125,6 @@ def read_all_files():
 
 
 def execute_operations_in_beam(
-    pipeline: beam.Pipeline,
     record_set: str,
     operations: Operations,
     filters: Mapping[str, Any] | None = None,
@@ -181,19 +176,15 @@ def execute_operations_in_beam(
     for operation in operations_in_memory:
         # If there is no FilterFiles, we return the PCollection without parallelization.
         if operation == target:
-            return (
-                pipeline
-                | beam.Create([(0, *operation.inputs)])
-                | _beam_operation_with_index(operation, sys.maxsize, stage_prefix)
+            return beam.Create([(0, *operation.inputs)]) | _beam_operation_with_index(
+                operation, sys.maxsize, stage_prefix
             )
         else:
             operation(set_output_in_memory=True)
 
     files = filter_files.output  # even for large datasets, this can be handled in RAM.
     # We first shard by file and assign a shard_index.
-    pipeline = pipeline | f"{stage_prefix} Shard by files with index" >> beam.Create(
-        enumerate(files)
-    )
+    pipeline = beam.Create(enumerate(files))
     num_shards = len(files)
     if not num_shards:
         raise ValueError(