RFR(S): 8223217: [TESTBUG] Create JFR tests with JMX across container boundary

[mikhailo.seledtsov at oracle.com]

Hi Erik,

On 12/4/19 11:30 PM, Erik Gahlin wrote:
> Hi Misha,
>
> The recording may complete before:
>
> while (r.getRecordings().get(0).getState() != RecordingState.STOPPED)
>
> is reached, or the recording may mot even be created (added to the list). This will result in an IndexOutOfBoundsException.
Right. I did not account for that.
>
> In my example I worked around it by looping over the list (possibly empty) and by not closing the recording I could be sure that the STOPPED state will eventually be seen. When the recording is closed it will disappear from the list.

I will use your example then, with one change. Instead of existing the 
test once (r.getState() == RecordingState.STOPPED) is true, the test 
will break. If child process exits right away, this will result in 
closing of the container, depriving the main process the opportunity to 
transfer the recording. Perhaps, I should break instead of 
System.exit(), and then have another loop to wait for all the recordings 
to close (r.getRecordings() become empty). After stopping the recording 
the main process transfers the recordings to the "host" system from the 
container, and then closes the recording. This will signal the 
"child/observed" process to "exit". E.g.:

         // Wait for recording to be transferred and be closed
         while 
(!FlightRecorder.getFlightRecorder().getRecordings().isEmpty()) {
             Thread.sleep(100);
         }

         System.out.println("Leaving main()");

Let me know if you see any problems with this approach.

Thank you,

Misha

> If you think the test recording should be closed, you could find some other means to communicate to the child process. For example, create two new recordings when the test recording has been closed and then in the loop check the count and if it is two exit the application.
>
> Erik
>
>> On 5 Dec 2019, at 05:53, mikhailo.seledtsov at oracle.com wrote:
>>
>> Hi Erik,
>>      I have followed your suggestions, but have modified the code a bit in the event producer class from
>>      your original. First the child "event producer" process waits for the JFR system/recorder to be initialized,
>>      then waits for recording to stop, and after that waiting for recording(s) to close; the main test process
>>      will transfer recording first, then close it.
>>
>>      Updated webrev: http://cr.openjdk.java.net/~mseledtsov/8223217.02/
>>
>>      I ran the test 20 times in our test lab, all PASS
>>
>>
>> Thank you,
>> Misha
>>
>> On 12/4/19 10:02 AM, Mikhailo Seledtsov wrote:
>>> Hi Erik,
>>>
>>>    Thank you for reviewing the test, and thanks for recommendations. I will make the updates according to your recommendations, and will post updated webrev after some testing.
>>>
>>>
>>> Misha
>>>
>>> On 12/3/19, 11:46 AM, Erik Gahlin wrote:
>>>> Hi Misha,
>>>>
>>>> Looks good overall, but it seems brittle to expect that the test will finish within the 10 s the EvenyGenerator runs
>>>>
>>>> Maybe you could make it deterministic by (for example) checking if the recording has stopped:
>>>>
>>>> int i = 0;
>>>> while (true) {
>>>>      SimpleEvent event = new SimpleEvent();
>>>>      event.msg = "Hello";
>>>>      event.count = i++;
>>>>      event.commit();
>>>>      Thread.sleep(10);
>>>>      if (FlightRecorder.isInitialized()) {
>>>>          for (Recording r : FlightRecorder.getFlightRecorder().getRecordings()) {
>>>>              if (r.getState() == RecordingState.STOPPED) {
>>>>                  System.exit(0);
>>>>              }
>>>>          }
>>>>      }
>>>> }
>>>>
>>>> and then not close the recording in the test?
>>>>
>>>> The test could also be made a bit more realistic if you run a default recording
>>>>
>>>> bean.setPredefinedConfiguration(recordingId, "default");
>>>>
>>>> Thanks
>>>> Erik
>>>>
>>>>
>>>>
>>>> On 2019-12-03 05:06, mikhailo.seledtsov at oracle.com wrote:
>>>>> Please review this change that tests JFR operations across container boundary while using JMX to control JFR.
>>>>> The test starts a container running a simple event producer, establishes a JMX connection, uses FlightRecorderMXBean to start the recording, stop and dump the recording, then transfers recording from the container.
>>>>> Simple verification is performed on the transferred recording, making sure that the expected test event is present.
>>>>>
>>>>>      JBS: https://bugs.openjdk.java.net/browse/JDK-8223217
>>>>>      Webrev: http://cr.openjdk.java.net/~mseledtsov/8223217.01/
>>>>>      Testing:
>>>>>          1. Ran the newly created test at least 30 times on a Linux-x64 host with docker engine configured - PASSED
>>>>>          2. Ran the test at least 20 times on a test cluster: ALL PASS
>>>>>          3. Ran all hotspot/containers tests on the test cluster: PASS
>>>>>
>>>>>
>>>>> Thank you,
>>>>> Misha
>>>>>