Use ImmutableWorkerInfo instead of ZKWorker

[nishantmonu51]

This PR is follow up changes for #2249 and #2585
#2249 uses Worker instead of ZkWorker whenever possible for task tiering.

This PR changes the behavior to expose ImmutableWorkerInfo from WorkerTaskRunner instead of Worker. ImmutableWorkerInfo has more details like list of running tasks and availability groups.

These extra details exposed are required for #2086 (implementing pending task based resource management strategy)

[nishantmonu51]

@gianm @drcrallen: Since its mostly related to your changes, please have a look at it.

[drcrallen]

... worker

[gianm]

Incomplete javadoc :(

[gianm]

@nishantmonu51 looks good other than some minor comments, let me know when you are ready and I can take another look

[nishantmonu51]

@drcrallen @gianm handed review comments, please check again.

[gianm]

👍 after travis

[fjy]

Tests run: 5, Failures: 0, Errors: 2, Skipped: 0, Time elapsed: 34.79 sec <<< FAILURE! - in io.druid.indexing.worker.WorkerTaskMonitorTest
testRestartCleansOldStatus(io.druid.indexing.worker.WorkerTaskMonitorTest) Time elapsed: 31.087 sec <<< ERROR!
java.lang.Exception: test timed out after 30000 milliseconds
at sun.misc.Unsafe.park(Native Method)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedInterruptibly(AbstractQueuedSynchronizer.java:994)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1303)
at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:236)
at io.druid.indexing.worker.WorkerTaskMonitor.stop(WorkerTaskMonitor.java:260)
at io.druid.indexing.worker.WorkerTaskMonitorTest.testRestartCleansOldStatus(WorkerTaskMonitorTest.java:331)
testRestartCleansOldStatus(io.druid.indexing.worker.WorkerTaskMonitorTest) Time elapsed: 31.087 sec <<< ERROR!
java.lang.IllegalStateException: not started
at com.google.common.base.Preconditions.checkState(Preconditions.java:176)
at io.druid.indexing.worker.WorkerTaskMonitor.stop(WorkerTaskMonitor.java:250)
at io.druid.indexing.worker.WorkerTaskMonitorTest.tearDown(WorkerTaskMonitorTest.java:205)
Running io.druid.indexing.worker.http.WorkerResourceTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 2.809 sec - in io.druid.indexing.worker.http.WorkerResourceTest
Running io.druid.indexing.worker.TaskAnnouncementTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.013 sec - in io.druid.indexing.worker.TaskAnnouncementTest
Running io.druid.indexing.appenderator.ActionBasedUsedSegmentCheckerTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec - in io.druid.indexing.appenderator.ActionBasedUsedSegmentCheckerTest
Running io.druid.server.initialization.IndexerZkConfigTest
Tests run: 5, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.874 sec - in io.druid.server.initialization.IndexerZkConfigTest
Results :
Tests in error:
io.druid.indexing.worker.WorkerTaskMonitorTest.testRestartCleansOldStatus(io.druid.indexing.worker.WorkerTaskMonitorTest)
Run 1: WorkerTaskMonitorTest.testRestartCleansOldStatus:331 » test timed out after 3...
Run 2: WorkerTaskMonitorTest.tearDown:205 » IllegalState not started

[drcrallen]

did these doc changes need to happen?

[nishantmonu51]

its done by intellij with the code formatting. so probably its fine to go along.

[drcrallen]

👍 (after travis) minor question about javadoc at author's discretion.