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From Aljoscha Krettek <aljos...@apache.org>
Subject Re: Writing an Integration test for flink-metrics
Date Fri, 13 Oct 2017 12:49:53 GMT
I think we could add this functionality to the (operator) test harnesses. I.e. add a mock MetricGroup
thingy in there that you can query to check the state of metrics. 

> On 13. Oct 2017, at 13:50, Chesnay Schepler <chesnay@apache.org> wrote:
> 
> I meant that you could unit-test the behavior of the function in isolation. You could
create a dummy metric group that
> verifies that the correct counters are being registered (based on names i guess), as
well as provide access to them.
> Mock some input and observe whether the counter value is being modified.
> 
> Whether this is a viable option depends a bit on the complexity of the function of course,
that is how much how mocking
> you would have to do.
> 
> On 13.10.2017 11:18, Piotr Nowojski wrote:
>> For testing Link applications in general you can read https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/stream/testing.html
<https://ci.apache.org/projects/flink/flink-docs-release-1.4/dev/stream/testing.html>
>> 
>> However as we said before, testing metrics would require using custom or a imx reporter.
>> 
>> Yes, please report this bug in Jira. 
>> 
>> Thanks, Piotrek
>> 
>>> On 13 Oct 2017, at 04:31, Colin Williams <colin.williams.seattle@gmail.com
<mailto:colin.williams.seattle@gmail.com>> wrote:
>>> 
>>> Team wants an integration test, I'm not sure what unit test you had in mind.
Actually feel that I've been trying to avoid the reporter method but that would be more end
to end.
>>> 
>>> The documentation for metrics and Scala are missing with the exception of Gauge:
https://ci.apache.org/projects/flink/flink-docs-release-1.3/monitoring/metrics.html <https://ci.apache.org/projects/flink/flink-docs-release-1.3/monitoring/metrics.html>
. Should I file a issue against that?
>>> 
>>> Then it leaves you guessing a little bit how to implement Counters. One approach
tried was using objects
>>> 
>>> object PointFilter extends RichMapFunction[...
>>>   @transient lazy val someCounter = getRuntimeContext.getMetricGroup.counter(...)
>>> 
>>> This allowed access to the counter before and after execution . However between
the unit tests the Counter kept its value also and that's a no for the test. Think that might
be an issue with ScalaTest. 
>>> 
>>> I've tried to get at the counter from some other directions like trying to find
a way to inject a reporter to get it's state. But don't see a way to do it. So probably the
best thing to do is fire up something to collect the metrics from the reporter.
>>> 
>>> On Thu, Oct 12, 2017 at 5:29 AM, Chesnay Schepler <chesnay@apache.org <mailto:chesnay@apache.org>>
wrote:
>>> Well damn, i should've read the second part of the initial mail.
>>> 
>>> I'm wondering though, could you not unit-test this behavior?
>>> 
>>> 
>>> On 12.10.2017 14:25, Chesnay Schepler wrote:
>>> You could also write a custom reporter that opens a socket or similar for communication
purposes.
>>> 
>>> You can then either query it for the metrics, or even just trigger the verification
in the reporter,
>>> and fail with an error if the reporter returns an error.
>>> 
>>> On 12.10.2017 14:02, Piotr Nowojski wrote:
>>> Hi,
>>> 
>>> Doing as you proposed using JMXReporter (or custom reporter) should work. I think
there is no easier way to do this at the moment.
>>> 
>>> Piotrek
>>> 
>>> On 12 Oct 2017, at 04:58, Colin Williams <colin.williams.seattle@gmail.com
<mailto:colin.williams.seattle@gmail.com>> wrote:
>>> 
>>> I have a RichMapFunction and I'd like to ensure Meter fields are properly incremented.
I've been trying to think of the best way to do this. Currently I think that I'd need to either
implement my own reporter (or use JMX) and write to a socket, create a listener and wait for
the reporter to send the message.
>>> 
>>> Is this a good approach for writing the test, or should I be considering something
else?
>>> 
>>> 
>>> 
>>> 
>>> 
>> 
> 


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