[GitHub] flink pull request #6047: [FLINK-8160]Extend OperatorHarness to expose...

[wangtuo21 <gi...@git.apache.org>]

GitHub user wangtuo21 opened a pull request:

    https://github.com/apache/flink/pull/6047

    [FLINK-8160]Extend OperatorHarness to expose...

    ...metricsGroup

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/wangtuo21/flink master

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/flink/pull/6047.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #6047
    
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commit 997e87b419c73643e93e74b96a350865e4ec64b0
Author: wangtuo21 <37...@...>
Date:   2018-05-19T17:20:49Z

    [FLINK-8160]Extend OperatorHarness to expose...
    
    ...metricsGroup

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[GitHub] flink issue #6047: [FLINK-8160]Extend OperatorHarness to expose...

[zentol <gi...@git.apache.org>]

Github user zentol commented on the issue:

    https://github.com/apache/flink/pull/6047
  
    Please explain how this solution allows the user of a `AbstractStreamOperatorTestHarness to access the metrics registered by contained operator.


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[GitHub] flink issue #6047: [FLINK-8160]Extend OperatorHarness to expose...

[zentol <gi...@git.apache.org>]

Github user zentol commented on the issue:

    https://github.com/apache/flink/pull/6047
  
    No, this still doesn't work.
    
    The MetricGroup you're trying to expose is created in `AbstractStreamOperator#setup`. However, the parent MetricGroup retrieved through `Environment#getMetricGroup` is null since this method is never mocked for the `MockEnvironment` in `AbstractStreamOperatorTestHarness`.  Thus, in  `AbstractStreamOperator#setup` we're entering the fail-safe block which creates a dummy `MetricGroup` that never stores anything.
    As such no metric can actually be retrieved from the `MetricGroup`.
    
    Please, ask questions if you don't know to fix an issue, or hot verify the fix. And at the very least try it out _once_, otherwise you're just wasting the committers' time.
    
    For a proper solution you have to create a `TaskMetricGroup` in the `AbstractStreamOperatorTestHarness`, which you then use in the `MockEnvironment` by returning it from `Environment#getMetricGroup`
    With this scheme however metrics are only available while the task hasn't been closed (as metrics are cleaned up), so for better usability your `TaskMetricGroup` must override `TaskMetricGroup#getOperator` to return a special `OperatorMetricGroup` that also stores registered metrics in the `AbstractStreamOperatorTestHarness`. We do not store them indefinitely in the `OperatorMetricGroup` since that would change one of the core behaviors of the `MetricGroup`. Finally, add a `getMetrics` method to the `AbstractStreamOperatorTestHarness` to actually access registered metrics.



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[GitHub] flink issue #6047: [FLINK-8160]Extend OperatorHarness to expose...

[wangtuo21 <gi...@git.apache.org>]

Github user wangtuo21 commented on the issue:

    https://github.com/apache/flink/pull/6047
  
    @zentol , I misunderstood the request.  Does it go in the right direction now? Thank you


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[GitHub] flink pull request #6047: [FLINK-8160]Extend OperatorHarness to expose...

[asfgit <gi...@git.apache.org>]

Github user asfgit closed the pull request at:

    https://github.com/apache/flink/pull/6047


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