Writing an Integration test for flink-metrics

[Colin Williams]

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?

[Piotr Nowojski]

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 <[hidden email]> 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?

[Chesnay Schepler]

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 <[hidden email]> 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?
>

[Chesnay Schepler]

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
>>> <[hidden email]> 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?
>>
>
>

[Colin Williams]

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 . 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 <[hidden email]> 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 <[hidden email]> 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?

[Piotr Nowojski]

For testing Link applications in general you can read 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 <[hidden email]> 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 . 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 <[hidden email]> 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 <[hidden email]> 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?

[Chesnay Schepler]

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

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 <[hidden email]> 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 . 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 <[hidden email]> 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 <[hidden email]> 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?

[Aljoscha Krettek]

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 <[hidden email]> 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

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 <[hidden email]> 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 . 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 <[hidden email]> 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 <[hidden email]> 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?

[Martin Eden]

Hi,

Not merged in yet but this is an example pr that is mocking metrics and checking they are properly updated:

https://github.com/apache/flink/pull/4725

On Fri, Oct 13, 2017 at 1:49 PM, Aljoscha Krettek <[hidden email]> wrote:

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 <[hidden email]> 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

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 <[hidden email]> 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 . 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 <[hidden email]> 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 <[hidden email]> 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?

[Colin Williams]

Thanks for the help. I ended up creating a custom metric reporter and accessing it's fields in an integration test. However I do think that the test that Martin checked in is another good way to test. I opened https://issues.apache.org/jira/browse/FLINK-7907 regarding the missing Scala examples in the metrics documentation. I can take a stab at that on the weekend if somebody doesn't beat me to it.

On Fri, Oct 13, 2017 at 6:09 AM, Martin Eden <[hidden email]> wrote:

Hi,

Not merged in yet but this is an example pr that is mocking metrics and checking they are properly updated:

https://github.com/apache/flink/pull/4725

On Fri, Oct 13, 2017 at 1:49 PM, Aljoscha Krettek <[hidden email]> wrote:

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 <[hidden email]> 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

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 <[hidden email]> 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 . 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 <[hidden email]> 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 <[hidden email]> 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?