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https://issues.apache.org/jira/browse/BEAM-3736?focusedWorklogId=506915&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-506915
]
ASF GitHub Bot logged work on BEAM-3736:
----------------------------------------
Author: ASF GitHub Bot
Created on: 03/Nov/20 14:00
Start Date: 03/Nov/20 14:00
Worklog Time Spent: 10m
Work Description: tvalentyn commented on a change in pull request #13048:
URL: https://github.com/apache/beam/pull/13048#discussion_r516397331
##########
File path: sdks/python/apache_beam/transforms/userstate.py
##########
@@ -357,6 +357,10 @@ def prefetch(self):
# The default implementation here does nothing.
pass
+ def finalize(self):
Review comment:
@robertwb do you see any concerns with adding a top level `finalize`
method here?
##########
File path: sdks/python/apache_beam/runners/dataflow/dataflow_runner.py
##########
@@ -411,6 +411,33 @@ def visit_transform(self, transform_node):
return FlattenInputVisitor()
+ @staticmethod
+ def combinefn_visitor():
+ # Imported here to avoid circular dependencies.
+ from apache_beam.pipeline import PipelineVisitor
+ from apache_beam import core
+
+ class CombineFnVisitor(PipelineVisitor):
+ """Checks if `CombineFn` has non-default setup or teardown methods.
+ If yes, raises `ValueError`.
+ """
+ def visit_transform(self, applied_transform):
+ transform = applied_transform.transform
+ if isinstance(transform, core.ParDo) and isinstance(
+ transform.fn, core.CombineValuesDoFn):
+ if self._overrides_setup_or_teardown(transform.fn.combinefn):
+ raise ValueError(
+ 'CombineFn.setup and CombineFn.teardown are '
+ 'not supported with non-portable Dataflow '
+ 'runner. Please use Dataflow Runner V2 instead.')
+
+ @staticmethod
+ def _overrides_setup_or_teardown(combinefn):
+ return combinefn.__class__.setup is not core.CombineFn.setup or \
Review comment:
nit: prefer to use `()` instead of `\` .
##########
File path: sdks/python/apache_beam/transforms/core.py
##########
@@ -1975,10 +1990,13 @@ def add_input_types(transform):
return combined
if self.has_defaults:
- combine_fn = (
- self.fn if isinstance(self.fn, CombineFn) else
- CombineFn.from_callable(self.fn))
- default_value = combine_fn.apply([], *self.args, **self.kwargs)
+ combine_fn = copy.deepcopy(self.fn) if isinstance(self.fn, CombineFn) \
Review comment:
nit:
[prefer](https://www.python.org/dev/peps/pep-0008/#:~:text=The%20preferred%20way%20of%20wrapping,a%20backslash%20for%20line%20continuation.)
using () to line continuation token.
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Issue Time Tracking
-------------------
Worklog Id: (was: 506915)
Time Spent: 9h 20m (was: 9h 10m)
> Add SetUp() and TearDown() for CombineFns
> -----------------------------------------
>
> Key: BEAM-3736
> URL: https://issues.apache.org/jira/browse/BEAM-3736
> Project: Beam
> Issue Type: Improvement
> Components: beam-model, sdk-py-core
> Reporter: Chuan Yu Foo
> Assignee: Kamil Wasilewski
> Priority: P3
> Time Spent: 9h 20m
> Remaining Estimate: 0h
>
> I have a CombineFn that has a large amount of state that needs to be loaded
> once before it can add_input or merge_combiners (for example, the CombineFn
> might load up a large lookup table used for combining).
> Right now, to initialise this state, for each of the methods, I check if the
> state has already been initialised, and if not, I initialise it. It would be
> nice if CombineFn provided a SetUp() method that is called once to initialise
> this state (and a corresponding TearDown() method to clean up this state if
> necessary).
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