Change getBaselineAasignment/getBestPossibleAssignment to account for partial-WAGED clusters

[NealSun96]

Issues

• My PR addresses the following Helix issues and references them in the PR description:

Fixes #1166

Description

• The following tests are written for this issue:
  testPartialBaselineAvailability

• Here are some details about my PR, including screenshots of any UI changes:

WAGED Rebalancer by design only supports one-off migration of resources. As a result, its getBaselineAssignment() did not consider the case of a cluster that's partially managed by WAGED. It tries to get baselines for all resources from the cluster; if there's no baseline data, it gets current states for all resources as a fallback. It doesn't care for resources that don't have baseline while other resources have baselines - when that's the case, the resources that don't have baseline will not fallback to their current states; they will simply not have baselines. A similar problem happens to getBestPossibleAssignment().

The logic is now changed to a per resource level. If a resource has baseline, the baseline will be used; else, the current state will be used. getBestPossibleAssignment() will be fixed the same way.

Tests

• The following is the result of the "mvn test" command on the appropriate module:

[ERROR] Tests run: 1155, Failures: 5, Errors: 0, Skipped: 1, Time elapsed: 4,324.66 s <<< FAILURE! - in TestSuite
[ERROR] testResourceSubset(org.apache.helix.tools.TestClusterStateVerifier)  Time elapsed: 1.025 s  <<< FAILURE!
org.apache.helix.HelixException: Failed to create pause signal
        at org.apache.helix.tools.TestClusterStateVerifier.testResourceSubset(TestClusterStateVerifier.java:115)

[ERROR] afterMethod(org.apache.helix.tools.TestClusterStateVerifier)  Time elapsed: 1.062 s  <<< FAILURE!
java.lang.IllegalStateException: ZkClient already closed!
        at org.apache.helix.tools.TestClusterStateVerifier.afterMethod(TestClusterStateVerifier.java:98)

[ERROR] testCustomizedViewAggregation(org.apache.helix.integration.TestCustomizedViewAggregation)  Time elapsed: 12.133 s  <<< FAILURE!
java.lang.AssertionError: expected:<true> but was:<false>
        at org.apache.helix.integration.TestCustomizedViewAggregation.validateAggregationSnapshot(TestCustomizedViewAggregation.java:238)
        at org.apache.helix.integration.TestCustomizedViewAggregation.testCustomizedViewAggregation(TestCustomizedViewAggregation.java:394)

[ERROR] testStateTransitionTimeOut(org.apache.helix.integration.paticipant.TestStateTransitionTimeoutWithResource)  Time elapsed: 36.061 s  <<< FAILURE!
java.lang.AssertionError: expected:<true> but was:<false>
        at org.apache.helix.integration.paticipant.TestStateTransitionTimeoutWithResource.testStateTransitionTimeOut(TestStateTransitionTimeoutWithResource.java:171)

[ERROR] testPeriodicRefresh(org.apache.helix.integration.spectator.TestRoutingTableProviderPeriodicRefresh)  Time elapsed: 2.015 s  <<< FAILURE!
java.lang.AssertionError: expected:<7> but was:<6>
        at org.apache.helix.integration.spectator.TestRoutingTableProviderPeriodicRefresh.testPeriodicRefresh(TestRoutingTableProviderPeriodicRefresh.java:192)

[INFO] 
[INFO] Results:
[INFO] 
[ERROR] Failures: 
[ERROR]   TestCustomizedViewAggregation.testCustomizedViewAggregation:394->validateAggregationSnapshot:238 expected:<true> but was:<false>
[ERROR]   TestStateTransitionTimeoutWithResource.testStateTransitionTimeOut:171 expected:<true> but was:<false>
[ERROR]   TestRoutingTableProviderPeriodicRefresh.testPeriodicRefresh:192 expected:<7> but was:<6>
[ERROR]   TestClusterStateVerifier.afterMethod:98 » IllegalState ZkClient already closed...
[ERROR]   TestClusterStateVerifier.testResourceSubset:115 » Helix Failed to create pause...
[INFO] 
[ERROR] Tests run: 1155, Failures: 5, Errors: 0, Skipped: 1
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  01:12 h
[INFO] Finished at: 2020-07-22T18:49:39-07:00
[INFO] ------------------------------------------------------------------------

Rerun

[INFO] Tests run: 6, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 38.505 s - in TestSuite
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 6, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  43.912 s
[INFO] Finished at: 2020-07-22T19:12:42-07:00
[INFO] ------------------------------------------------------------------------

Commits

• My commits all reference appropriate Apache Helix GitHub issues in their subject lines. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Code Quality

• My diff has been formatted using helix-style.xml
  (helix-style-intellij.xml if IntelliJ IDE is used)

[jiajunwang]

Please do the same for getBestPossibleAssignment too.

[jiajunwang]

Let's add a test case to cover this scenario.

[jiajunwang]

LGTM!

[NealSun96]

This PR is ready to be merged, approved by @jiajunwang
Final commit message:

Change getBaselineAasignment/getBestPossibleAssignment to account for partial-WAGED clusters

The logics are now changed to a per resource level. If a resource has baseline/best possible, the baseline/best possible will be used; else, the current state will be used.