RATIS-2343. Replace string reasons with enum constants in log messages.

Author: szetszwo

ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java

@@ -83,7 +83,7 @@
 import org.apache.ratis.server.impl.RetryCacheImpl.CacheEntry;
 import org.apache.ratis.server.impl.ServerImplUtils.ConsecutiveIndices;
 import org.apache.ratis.server.impl.ServerImplUtils.NavigableIndices;
-import org.apache.ratis.server.leader.LeaderState;
+import org.apache.ratis.server.leader.LeaderState.StepDownReason;
 import org.apache.ratis.server.metrics.LeaderElectionMetrics;
 import org.apache.ratis.server.metrics.RaftServerMetricsImpl;
 import org.apache.ratis.server.protocol.RaftServerAsynchronousProtocol;
@@ -409,7 +409,7 @@ boolean start() throws IOException {
       startAsPeer(RaftPeerRole.LISTENER);
     } else {
       LOG.info("{}: start with initializing state, conf={}", getMemberId(), conf);
-      setRole(RaftPeerRole.FOLLOWER, "start");
+      setRole(RaftPeerRole.FOLLOWER, "NOT_IN_CONF");
     }
 
     jmxAdapter.registerMBean();
@@ -859,7 +859,7 @@ private CompletableFuture<RaftClientReply> appendTransaction(
         cacheEntry.failWithReply(exceptionReply);
         // leader will step down here
         if (e.leaderShouldStepDown() && getInfo().isLeader()) {
-          leaderState.submitStepDownEvent(LeaderState.StepDownReason.STATE_MACHINE_EXCEPTION);
+          leaderState.submitStepDownEvent(StepDownReason.STATE_MACHINE_EXCEPTION);
         }
         return CompletableFuture.completedFuture(exceptionReply);
       }
@@ -909,7 +909,7 @@ private RaftClientReply combineReplies(RaftClientReply reply, RaftClientReply wa
   }
 
   void stepDownOnJvmPause() {
-    role.getLeaderState().ifPresent(leader -> leader.submitStepDownEvent(LeaderState.StepDownReason.JVM_PAUSE));
+    role.getLeaderState().ifPresent(leader -> leader.submitStepDownEvent(StepDownReason.JVM_PAUSE));
   }
 
   private RaftClientRequest filterDataStreamRaftClientRequest(RaftClientRequest request)
@@ -1580,11 +1580,11 @@ leaderId, getMemberId(), currentTerm, followerCommit, state.getNextIndex(),
             AppendResult.NOT_LEADER, callId, RaftLog.INVALID_LOG_INDEX, isHeartbeat));
       }
       try {
-        future = changeToFollowerAndPersistMetadata(leaderTerm, true, "appendEntries");
+        future = changeToFollowerAndPersistMetadata(leaderTerm, true, Op.APPEND_ENTRIES);
       } catch (IOException e) {
         return JavaUtils.completeExceptionally(e);
       }
-      state.setLeader(leaderId, "appendEntries");
+      state.setLeader(leaderId, Op.APPEND_ENTRIES);
 
       if (!proto.getInitializing() && lifeCycle.compareAndTransition(State.STARTING, State.RUNNING)) {
         role.startFollowerState(this, Op.APPEND_ENTRIES);

ratis-server/src/main/java/org/apache/ratis/server/impl/ServerProtoUtils.java

@@ -178,8 +178,12 @@ static ServerRpcProto toServerRpcProto(RaftPeer peer, long delay) {
       // if no peer information return empty
       return ServerRpcProto.getDefaultInstance();
     }
+    return  toServerRpcProto(peer.getRaftPeerProto(), delay);
+  }
+
+  static ServerRpcProto toServerRpcProto(RaftPeerProto peer, long delay) {
     return ServerRpcProto.newBuilder()
-        .setId(peer.getRaftPeerProto())
+        .setId(peer)
         .setLastRpcElapsedTimeMs(delay)
         .build();
   }

ratis-server/src/main/java/org/apache/ratis/server/impl/SnapshotInstallationHandler.java

@@ -29,10 +29,10 @@
 import org.apache.ratis.proto.RaftProtos.ServerRpcProto;
 import org.apache.ratis.protocol.RaftGroupId;
 import org.apache.ratis.protocol.RaftGroupMemberId;
-import org.apache.ratis.protocol.RaftPeer;
 import org.apache.ratis.protocol.RaftPeerId;
 import org.apache.ratis.server.RaftServerConfigKeys;
-import org.apache.ratis.server.protocol.RaftServerProtocol;
+import org.apache.ratis.server.impl.FollowerState.UpdateType;
+import org.apache.ratis.server.protocol.RaftServerProtocol.Op;
 import org.apache.ratis.server.protocol.TermIndex;
 import org.apache.ratis.server.raftlog.LogProtoUtils;
 import org.apache.ratis.server.util.ServerStringUtils;
@@ -173,16 +173,16 @@ private CompletableFuture<InstallSnapshotReplyProto> checkAndInstallSnapshot(Ins
     final long lastIncludedIndex = lastIncluded.getIndex();
     final CompletableFuture<Void> future;
     synchronized (server) {
-      final boolean recognized = state.recognizeLeader(RaftServerProtocol.Op.INSTALL_SNAPSHOT, leaderId, leaderTerm);
+      final boolean recognized = state.recognizeLeader(Op.INSTALL_SNAPSHOT, leaderId, leaderTerm);
       currentTerm = state.getCurrentTerm();
       if (!recognized) {
         return CompletableFuture.completedFuture(toInstallSnapshotReplyProto(leaderId, getMemberId(),
             currentTerm, snapshotChunkRequest.getRequestIndex(), InstallSnapshotResult.NOT_LEADER));
       }
-      future = server.changeToFollowerAndPersistMetadata(leaderTerm, true, "installSnapshot");
-      state.setLeader(leaderId, "installSnapshot");
+      future = server.changeToFollowerAndPersistMetadata(leaderTerm, true, Op.INSTALL_SNAPSHOT);
+      state.setLeader(leaderId, Op.INSTALL_SNAPSHOT);
 
-      server.updateLastRpcTime(FollowerState.UpdateType.INSTALL_SNAPSHOT_START);
+      server.updateLastRpcTime(UpdateType.INSTALL_SNAPSHOT_START);
       long callId = chunk0CallId.get();
       // 1. leaderTerm < currentTerm will never come here
       // 2. leaderTerm == currentTerm && callId == request.getCallId()
@@ -229,7 +229,7 @@ private CompletableFuture<InstallSnapshotReplyProto> checkAndInstallSnapshot(Ins
           chunk0CallId.set(-1);
         }
       } finally {
-        server.updateLastRpcTime(FollowerState.UpdateType.INSTALL_SNAPSHOT_COMPLETE);
+        server.updateLastRpcTime(UpdateType.INSTALL_SNAPSHOT_COMPLETE);
       }
     }
     if (snapshotChunkRequest.getDone()) {
@@ -249,15 +249,15 @@ private CompletableFuture<InstallSnapshotReplyProto> notifyStateMachineToInstall
     final long firstAvailableLogIndex = firstAvailableLogTermIndex.getIndex();
     final CompletableFuture<Void> future;
     synchronized (server) {
-      final boolean recognized = state.recognizeLeader("notifyInstallSnapshot", leaderId, leaderTerm);
+      final boolean recognized = state.recognizeLeader(UpdateType.INSTALL_SNAPSHOT_NOTIFICATION, leaderId, leaderTerm);
       currentTerm = state.getCurrentTerm();
       if (!recognized) {
         return CompletableFuture.completedFuture(toInstallSnapshotReplyProto(leaderId, getMemberId(),
             currentTerm, InstallSnapshotResult.NOT_LEADER));
       }
-      future = server.changeToFollowerAndPersistMetadata(leaderTerm, true, "installSnapshot");
-      state.setLeader(leaderId, "installSnapshot");
-      server.updateLastRpcTime(FollowerState.UpdateType.INSTALL_SNAPSHOT_NOTIFICATION);
+      future = server.changeToFollowerAndPersistMetadata(leaderTerm, true, UpdateType.INSTALL_SNAPSHOT_NOTIFICATION);
+      state.setLeader(leaderId, UpdateType.INSTALL_SNAPSHOT_NOTIFICATION);
+      server.updateLastRpcTime(UpdateType.INSTALL_SNAPSHOT_NOTIFICATION);
 
       if (inProgressInstallSnapshotIndex.compareAndSet(INVALID_LOG_INDEX, firstAvailableLogIndex)) {
         LOG.info("{}: Received notification to install snapshot at index {}", getMemberId(), firstAvailableLogIndex);
@@ -292,7 +292,7 @@ private CompletableFuture<InstallSnapshotReplyProto> notifyStateMachineToInstall
         // For the cases where RaftConf is empty on newly started peer with empty peer list,
         // we retrieve leader info from installSnapShotRequestProto.
         final RoleInfoProto proto = leaderProto == null || server.getRaftConf().getPeer(state.getLeaderId()) != null?
-            server.getRoleInfoProto(): getRoleInfoProto(ProtoUtils.toRaftPeer(leaderProto));
+            server.getRoleInfoProto(): getRoleInfoProto(leaderProto);
         // This is the first installSnapshot notify request for this term and
         // index. Notify the state machine to install the snapshot.
         LOG.info("{}: notifyInstallSnapshot: nextIndex is {} but the leader's first available index is {}.",
@@ -386,7 +386,7 @@ private CompletableFuture<InstallSnapshotReplyProto> notifyStateMachineToInstall
     }
   }
 
-  private RoleInfoProto getRoleInfoProto(RaftPeer leader) {
+  private RoleInfoProto getRoleInfoProto(RaftPeerProto leader) {
     final RoleInfo role = server.getRole();
     final Optional<FollowerState> fs = role.getFollowerState();
     final ServerRpcProto leaderInfo = toServerRpcProto(leader,