Source code for apache_beam.transforms.sideinputs

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"""Internal side input transforms and implementations.

For internal use only; no backwards-compatibility guarantees.

Important: this module is an implementation detail and should not be used
directly by pipeline writers. Instead, users should use the helper methods
AsSingleton, AsIter, AsList and AsDict in apache_beam.pvalue.

# pytype: skip-file

import re
from typing import TYPE_CHECKING
from typing import Any
from typing import Callable
from typing import Dict

from apache_beam.transforms import window

  from apache_beam import pvalue

WindowMappingFn = Callable[[window.BoundedWindow], window.BoundedWindow]

SIDE_INPUT_PREFIX = 'python_side_input'


# Top-level function so we can identify it later.
def _global_window_mapping_fn(w, global_window=window.GlobalWindow()):
  # type: (...) -> window.GlobalWindow
  return global_window

[docs]def default_window_mapping_fn(target_window_fn): # type: (window.WindowFn) -> WindowMappingFn if target_window_fn == window.GlobalWindows(): return _global_window_mapping_fn if isinstance(target_window_fn, window.Sessions): raise RuntimeError("Sessions is not allowed in side inputs") def map_via_end(source_window): # type: (window.BoundedWindow) -> window.BoundedWindow return list( target_window_fn.assign( window.WindowFn.AssignContext(source_window.max_timestamp())))[-1] return map_via_end
[docs]def get_sideinput_index(tag): # type: (str) -> int match = re.match(SIDE_INPUT_REGEX, tag, re.DOTALL) if match: return int( else: raise RuntimeError("Invalid tag %r" % tag)
[docs]class SideInputMap(object): """Represents a mapping of windows to side input values.""" def __init__( self, view_class, # type: pvalue.AsSideInput view_options, iterable): self._window_mapping_fn = view_options.get( 'window_mapping_fn', _global_window_mapping_fn) self._view_class = view_class self._view_options = view_options self._iterable = iterable self._cache = {} # type: Dict[window.BoundedWindow, Any] def __getitem__(self, window): # type: (window.BoundedWindow) -> Any if window not in self._cache: target_window = self._window_mapping_fn(window) self._cache[window] = self._view_class._from_runtime_iterable( _FilteringIterable(self._iterable, target_window), self._view_options) return self._cache[window]
[docs] def is_globally_windowed(self): # type: () -> bool return self._window_mapping_fn == _global_window_mapping_fn
class _FilteringIterable(object): """An iterable containing only those values in the given window. """ def __init__(self, iterable, target_window): self._iterable = iterable self._target_window = target_window def __iter__(self): for wv in self._iterable: if self._target_window in yield wv.value def __reduce__(self): # Pickle self as an already filtered list. return list, (list(self), )