sdks/python/apache_beam/options/pipeline_options_context.py

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"""Context-scoped access to pipeline options during graph construction and
translation.

This module provides thread-safe and async-safe access to globally-available
instances of PipelineOptions using contextvars, scoped by the current pipeline.
It allows components like transforms and coders to access the pipeline's
configuration without requiring explicit parameter passing through every
level of the call stack.

For internal use only; no backwards-compatibility guarantees.
"""

from contextlib import contextmanager
from contextvars import ContextVar
from typing import TYPE_CHECKING
from typing import Optional

if TYPE_CHECKING:
  from apache_beam.options.pipeline_options import PipelineOptions

# The contextvar holding the current pipeline's options.
# Each thread and each asyncio task gets its own isolated copy.
_pipeline_options: ContextVar[Optional['PipelineOptions']] = ContextVar(
    'pipeline_options', default=None)


def get_pipeline_options() -> Optional['PipelineOptions']:
  """Get the current pipeline's options from the context.

  Returns:
    The PipelineOptions for the currently executing pipeline operation,
    or None if called outside of a pipeline context.
  """
  return _pipeline_options.get()


@contextmanager
def scoped_pipeline_options(options: Optional['PipelineOptions']):
  """Context manager that sets pipeline options for the duration of a block.

  Args:
    options: The PipelineOptions to make available during this scope.
  """
  token = _pipeline_options.set(options)
  try:
    yield
  finally:
    _pipeline_options.reset(token)