HBASE-27448 Add an admin method to get replication enabled state

hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java

@@ -2555,4 +2555,12 @@ List<LogEntry> getLogEntries(Set<ServerName> serverNames, String logType, Server
    * Flush master local region
    */
   void flushMasterStore() throws IOException;
+
+  /**
+   * Check if a replication peer is enabled.
+   * @param peerId id of replication peer to check
+   * @return <code>true</code> if replication peer is enabled
+   * @throws IOException if a remote or network exception occurs
+   */
+  boolean isReplicationPeerEnabled(String peerId) throws IOException;
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java

@@ -1084,4 +1084,9 @@ public List<LogEntry> getLogEntries(Set<ServerName> serverNames, String logType,
   public void flushMasterStore() throws IOException {
     get(admin.flushMasterStore());
   }
+
+  @Override
+  public boolean isReplicationPeerEnabled(String peerId) throws IOException {
+    return get(admin.isReplicationPeerEnabled(peerId));
+  }
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java

@@ -1776,4 +1776,12 @@ CompletableFuture<List<LogEntry>> getLogEntries(Set<ServerName> serverNames, Str
    * Flush master local region
    */
   CompletableFuture<Void> flushMasterStore();
+
+  /**
+   * Check if a replication peer is enabled.
+   * @param peerId id of replication peer to check
+   * @return true if replication peer is enabled. The return value will be wrapped by a
+   *         {@link CompletableFuture}.
+   */
+  CompletableFuture<Boolean> isReplicationPeerEnabled(String peerId);
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncHBaseAdmin.java

@@ -959,4 +959,9 @@ public CompletableFuture<List<LogEntry>> getLogEntries(Set<ServerName> serverNam
   public CompletableFuture<Void> flushMasterStore() {
     return wrap(rawAdmin.flushMasterStore());
   }
+
+  @Override
+  public CompletableFuture<Boolean> isReplicationPeerEnabled(String peerId) {
+    return wrap(rawAdmin.isReplicationPeerEnabled(peerId));
+  }
 }

hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java

@@ -192,6 +192,8 @@
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetProcedureResultResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetProceduresRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetProceduresResponse;
+import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetReplicationPeerStateRequest;
+import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetReplicationPeerStateResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableDescriptorsRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableDescriptorsResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableNamesRequest;
@@ -4284,4 +4286,16 @@ Void> call(controller, stub, request.build(),
           (s, c, req, done) -> s.flushMasterStore(c, req, done), resp -> null))
       .call();
   }
+
+  @Override
+  public CompletableFuture<Boolean> isReplicationPeerEnabled(String peerId) {
+    GetReplicationPeerStateRequest.Builder request = GetReplicationPeerStateRequest.newBuilder();
+    request.setPeerId(peerId);
+    return this.<Boolean> newMasterCaller()
+      .action((controller, stub) -> this.<GetReplicationPeerStateRequest,
+        GetReplicationPeerStateResponse, Boolean> call(controller, stub, request.build(),
+          (s, c, req, done) -> s.isReplicationPeerEnabled(c, req, done),
+          resp -> resp.getIsEnabled()))
+      .call();
+  }
 }

hbase-protocol-shaded/src/main/protobuf/server/master/Master.proto

@@ -761,6 +761,13 @@ message ModifyColumnStoreFileTrackerResponse {
 message FlushMasterStoreRequest {}
 message FlushMasterStoreResponse {}
 
+message GetReplicationPeerStateRequest {
+  required string peer_id = 1;
+}
+message GetReplicationPeerStateResponse {
+  required bool is_enabled = 1;
+}
+
 service MasterService {
   /** Used by the client to get the number of regions that have received the updated schema */
   rpc GetSchemaAlterStatus(GetSchemaAlterStatusRequest)
@@ -1203,6 +1210,9 @@ service MasterService {
 
   rpc FlushMasterStore(FlushMasterStoreRequest)
     returns(FlushMasterStoreResponse);
+
+  rpc IsReplicationPeerEnabled(GetReplicationPeerStateRequest)
+    returns(GetReplicationPeerStateResponse);
 }
 
 // HBCK Service definitions.

hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java

@@ -246,6 +246,8 @@
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetProcedureResultResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetProceduresRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetProceduresResponse;
+import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetReplicationPeerStateRequest;
+import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetReplicationPeerStateResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetSchemaAlterStatusRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetSchemaAlterStatusResponse;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.GetTableDescriptorsRequest;
@@ -3491,4 +3493,16 @@ public FlushMasterStoreResponse flushMasterStore(RpcController controller,
     }
     return FlushMasterStoreResponse.newBuilder().build();
   }
+
+  @Override
+  public GetReplicationPeerStateResponse isReplicationPeerEnabled(RpcController controller,
+    GetReplicationPeerStateRequest request) throws ServiceException {
+    boolean isEnabled;
+    try {
+      isEnabled = server.getReplicationPeerManager().getPeerState(request.getPeerId());
+    } catch (ReplicationException ioe) {
+      throw new ServiceException(ioe);
+    }
+    return GetReplicationPeerStateResponse.newBuilder().setIsEnabled(isEnabled).build();
+  }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/replication/ReplicationPeerManager.java

@@ -271,6 +271,15 @@ private void setPeerState(String peerId, boolean enabled) throws ReplicationExce
       desc.getSyncReplicationState()));
   }
 
+  public boolean getPeerState(String peerId) throws ReplicationException {
+    ReplicationPeerDescription desc = peers.get(peerId);
+    if (desc != null) {
+      return desc.isEnabled();
+    } else {
+      throw new ReplicationException("Replication Peer of " + peerId + " does not exist.");
+    }
+  }
+
   public void enablePeer(String peerId) throws ReplicationException {
     setPeerState(peerId, true);
   }

hbase-server/src/test/java/org/apache/hadoop/hbase/replication/TestGetReplicationPeerState.java

@@ -0,0 +1,48 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.replication;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.testclassification.LargeTests;
+import org.apache.hadoop.hbase.testclassification.ReplicationTests;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+@Category({ ReplicationTests.class, LargeTests.class })
+public class TestGetReplicationPeerState extends TestReplicationBase {
+
+  @ClassRule
+  public static final HBaseClassTestRule CLASS_RULE =
+    HBaseClassTestRule.forClass(TestGetReplicationPeerState.class);
+
+  @Test
+  public void testGetReplicationPeerState() throws Exception {
+
+    // Test disable replication peer
+    hbaseAdmin.disableReplicationPeer("2");
+    assertFalse(hbaseAdmin.isReplicationPeerEnabled("2"));
+
+    // Test enable replication peer
+    hbaseAdmin.enableReplicationPeer("2");
+    assertTrue(hbaseAdmin.isReplicationPeerEnabled("2"));
+  }
+}

hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/VerifyingRSGroupAdmin.java

@@ -939,4 +939,9 @@ public Future<Void> modifyTableStoreFileTrackerAsync(TableName tableName, String
   public void flushMasterStore() throws IOException {
     admin.flushMasterStore();
   }
+
+  @Override
+  public boolean isReplicationPeerEnabled(String peerId) throws IOException {
+    return admin.isReplicationPeerEnabled(peerId);
+  }
 }

hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/client/ThriftAdmin.java

@@ -1314,4 +1314,9 @@ public Future<Void> modifyTableStoreFileTrackerAsync(TableName tableName, String
   public void flushMasterStore() throws IOException {
     throw new NotImplementedException("flushMasterStore not supported in ThriftAdmin");
   }
+
+  @Override
+  public boolean isReplicationPeerEnabled(String peerId) throws IOException {
+    throw new NotImplementedException("isReplicationPeerEnabled not supported in ThriftAdmin");
+  }
 }