[jira] [Created] (BEAM-6511) AbstractGlobalCombineFn hierarchy is inconsistent

["Nahuel Lofeudo (JIRA)" <ji...@apache.org>]

Nahuel Lofeudo created BEAM-6511:
------------------------------------

             Summary: AbstractGlobalCombineFn hierarchy is inconsistent
                 Key: BEAM-6511
                 URL: https://issues.apache.org/jira/browse/BEAM-6511
             Project: Beam
          Issue Type: Bug
          Components: runner-dataflow
    Affects Versions: 2.9.0
            Reporter: Nahuel Lofeudo
            Assignee: Tyler Akidau


Subclasses of AbstractGlobalCombineFn seem to be arranged in a way that prevents them from being used with the DataflowRunner. 

Subclasses of AbstractGlobalCombineFn are under either CombineFn or CombineFnWithContext, which seems to be in itself a CombineFn which has access to PipelineOptions and Side Inputs.

However, the DataflowRunner casts all combiners passed from user code to CombineFn (see [1]) which prevents combiners that extend CombineFnWithContext from being used there. 

 

For example: 
public class CustomCombinerFn extends CombineWithContext.CombineFnWithContext<...> \{...}
 
final PCollectionView<SomeObject<String>> newCollection = oldCollection
  .apply("Custom Combiner", Combine.globally(new CustomCombinerFn(filter)) 
  .withSideInputs(filter)
  .withoutDefaults()
  .asSingletonView());
 
IMHO either CombineFnWithContext should be a subclass of CombineFn or DataflowRunner should cast the combiner to AbstractGlobalCombineFn. 
 
[1] https://github.com/apache/beam/blob/b83b302ef97767e4ca245ea24e8bd40a6692e72c/runners/google-cloud-dataflow-java/src/main/java/org/apache/beam/runners/dataflow/DataflowRunner.java#L514



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)