Avoid using Ratis internal API

[kaijchen]

Summary Currently, Alluxio is using some internal API of Apache Ratis, causing compatibility issues during upgrades. For example: https://lists.apache.org/thread/2hzs61jzqjy0ktt6svv2ng6crh6t1f7q

Urgency It would be easier to upgrade Ratis in the future.

[ssz1997]

@jenoudet @tcrain @yuzhu FYI

[jenoudet]

Thanks for raising the issue. Could you point us towards parts of the code where we use Ratis's internal API using link to our own codebase?

[kaijchen]

Thanks for raising the issue. Could you point us towards parts of the code where we use Ratis's internal API using link to our own codebase?

Here is all the imports of classes in ratis-server.

./core/server/common/src/main/java/alluxio/master/journal/raft/JournalStateMachine.java:53:import org.apache.ratis.statemachine.impl.BaseStateMachine;
./core/server/common/src/main/java/alluxio/master/journal/raft/JournalStateMachine.java:54:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./core/server/common/src/main/java/alluxio/master/journal/raft/JournalStateMachine.java:55:import org.apache.ratis.statemachine.impl.SingleFileSnapshotInfo;
./core/server/common/src/main/java/alluxio/master/journal/raft/SnapshotReplicationManager.java:56:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./core/server/common/src/main/java/alluxio/master/journal/raft/SnapshotReplicationManager.java:57:import org.apache.ratis.statemachine.impl.SingleFileSnapshotInfo;
./core/server/common/src/main/java/alluxio/master/journal/raft/SnapshotUploader.java:29:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./core/server/common/src/main/java/alluxio/master/journal/raft/SnapshotDownloader.java:27:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./core/server/common/src/main/java/alluxio/master/journal/raft/SnapshotDownloader.java:28:import org.apache.ratis.statemachine.impl.SingleFileSnapshotInfo;
./core/server/common/src/main/java/alluxio/master/journal/raft/RaftJournalUtils.java:15:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./core/server/master/src/test/java/alluxio/master/journal/raft/RaftJournalTest.java:587:    Class<?> raftServerImpl = (Class.forName("org.apache.ratis.server.impl.RaftServerImpl"));
./core/server/master/src/test/java/alluxio/master/journal/raft/RaftJournalTest.java:597:    Class<?> raftServerImplClass = Class.forName("org.apache.ratis.server.impl.RaftServerImpl");
./core/server/master/src/test/java/alluxio/master/journal/raft/RaftJournalTest.java:602:    Class<?> serverStateClass = Class.forName("org.apache.ratis.server.impl.ServerState");
./core/server/master/src/test/java/alluxio/master/journal/raft/SnapshotReplicationManagerTest.java:47:import org.apache.ratis.server.storage.StorageImplUtils;
./core/server/master/src/test/java/alluxio/master/journal/raft/SnapshotReplicationManagerTest.java:48:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./core/server/master/src/test/java/alluxio/master/journal/raft/SnapshotReplicationManagerTest.java:49:import org.apache.ratis.statemachine.impl.SingleFileSnapshotInfo;
./core/server/master/src/main/java/alluxio/master/journal/tool/RaftJournalDumper.java:23:import org.apache.ratis.server.raftlog.segmented.LogSegment;
./core/server/master/src/main/java/alluxio/master/journal/tool/RaftJournalDumper.java:24:import org.apache.ratis.server.raftlog.segmented.LogSegmentPath;
./core/server/master/src/main/java/alluxio/master/journal/tool/RaftJournalDumper.java:26:import org.apache.ratis.server.storage.StorageImplUtils;
./core/server/master/src/main/java/alluxio/master/journal/tool/RaftJournalDumper.java:27:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./core/server/master/src/main/java/alluxio/master/journal/tool/RaftJournalDumper.java:28:import org.apache.ratis.statemachine.impl.SingleFileSnapshotInfo;
./tests/src/test/java/alluxio/server/ft/journal/raft/EmbeddedJournalIntegrationTestFaultTolerance.java:38:import org.apache.ratis.server.storage.StorageImplUtils;
./tests/src/test/java/alluxio/server/ft/journal/raft/EmbeddedJournalIntegrationTestFaultTolerance.java:39:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./tests/src/test/java/alluxio/server/ft/journal/raft/EmbeddedJournalIntegrationTestFaultTolerance.java:40:import org.apache.ratis.statemachine.impl.SingleFileSnapshotInfo;
./tests/src/test/java/alluxio/client/cli/JournalToolTest.java:48:import org.apache.ratis.server.storage.StorageImplUtils;
./tests/src/test/java/alluxio/client/cli/JournalToolTest.java:49:import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
./tests/src/test/java/alluxio/client/cli/JournalToolTest.java:50:import org.apache.ratis.statemachine.impl.SingleFileSnapshotInfo;

However, it's OK to reuse the implementation without using the internal API (so there might be false positives). For example:

// It's ok to reuse the implementation
StateMachineStorage storage = new SimpleStateMachineStorage();

// But it's not good to use the internal API
SimpleStateMachineStorage storage = new SimpleStateMachineStorage();

[kaijchen]

This issue is partially fixed by #16998

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