[jira] [Created] (BEAM-3323) Create a generator of finite-but-unbounded PCollection's for integration testing

["Eugene Kirpichov (JIRA)" <ji...@apache.org>]

Eugene Kirpichov created BEAM-3323:
--------------------------------------

             Summary: Create a generator of finite-but-unbounded PCollection's for integration testing
                 Key: BEAM-3323
                 URL: https://issues.apache.org/jira/browse/BEAM-3323
             Project: Beam
          Issue Type: New Feature
          Components: sdk-java-core
            Reporter: Eugene Kirpichov
            Assignee: Kenneth Knowles


Several IOs have features that exhibit nontrivial behavior when writing unbounded PCollection's - e.g. WriteFiles with windowed writes; BigQueryIO. We need to be able to write integration tests for these features.

Currently we have two ways to generate an unbounded PCollection without reading from a real-world external streaming system such as pubsub or kafka:

1) TestStream, which only works in direct runner - sufficient for some tests but not all: definitely not sufficient for large-scale tests or for tests that need to interact with a real instance of the external system (e.g. BigQueryIO). It is also quite verbose to use.
2) GenerateSequence.from(0) without a .to(), which returns an infinite amount of data.

GenerateSequence.from(a).to(b) returns a finite amount of data, but returns it as a bounded PCollection, and doesn't report the watermark.

I think the right thing to do here, for now, is to make GenerateSequence.from(a).to(b) have an option (e.g. ".asUnbounded()", where it will return an unbounded PCollection, go through UnboundedSource (or potentially via SDF in runners that support it), and track the watermark properly (or via a configurable watermark fn).



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)