Fixed - DNS change isn't detected in replicated mode #4437

redisson/src/main/java/org/redisson/connection/ReplicatedConnectionManager.java

@@ -17,7 +17,6 @@ package org.redisson.connection;
 
 import io.netty.util.concurrent.ScheduledFuture;
 import org.redisson.api.NodeType;
-import org.redisson.api.RFuture;
 import org.redisson.client.RedisClient;
 import org.redisson.client.RedisConnection;
 import org.redisson.client.RedisConnectionException;
@@ -163,49 +162,56 @@ public class ReplicatedConnectionManager extends MasterSlaveConnectionManager {
 
     private void checkNode(AsyncCountDownLatch latch, RedisURI uri, ReplicatedServersConfig cfg, Set<InetSocketAddress> slaveIPs) {
         CompletionStage<RedisConnection> connectionFuture = connectToNode(cfg, uri, uri.getHost());
-        connectionFuture.whenComplete((connection, exc) -> {
-            if (exc != null) {
-                log.error(exc.getMessage(), exc);
-                latch.countDown();
-                return;
-            }
-
-            if (isShuttingDown()) {
-                return;
-            }
+        connectionFuture
+                .thenCompose(c -> resolveIP(uri))
+                .thenCompose(ip -> {
+                    if (isShuttingDown()) {
+                        return CompletableFuture.completedFuture(null);
+                    }
 
-            RFuture<Map<String, String>> result = connection.async(RedisCommands.INFO_REPLICATION);
-            result.whenComplete((r, ex) -> {
-                if (ex != null) {
-                    log.error(ex.getMessage(), ex);
-                    latch.countDown();
-                    return;
-                }
+                    RedisConnection connection = connectionFuture.toCompletableFuture().join();
+                    if (!RedisURI.compare(connection.getRedisClient().getAddr(), ip)) {
+                        closeNodeConnection(connection);
+                        log.info("Hostname: " + uri + " has changed IP from: "
+                                    + connection.getRedisClient().getAddr() + " to " + ip);
+                        return CompletableFuture.<Map<String, String>>completedFuture(null);
+                    }
 
-                InetSocketAddress addr = connection.getRedisClient().getAddr();
-                Role role = Role.valueOf(r.get(ROLE_KEY));
-                if (Role.master.equals(role)) {
-                    InetSocketAddress master = currentMaster.get();
-                    if (master.equals(addr)) {
-                        log.debug("Current master {} unchanged", master);
-                    } else if (currentMaster.compareAndSet(master, addr)) {
-                        CompletableFuture<RedisClient> changeFuture = changeMaster(singleSlotRange.getStartSlot(), uri);
-                        changeFuture.exceptionally(e -> {
-                            log.error("Unable to change master to " + addr, e);
-                            currentMaster.compareAndSet(addr, master);
-                            return null;
-                        });
+                    return connection.async(RedisCommands.INFO_REPLICATION);
+                })
+                .thenCompose(r -> {
+                    if (r == null) {
+                        return CompletableFuture.completedFuture(null);
+                    }
+                    RedisConnection connection = connectionFuture.toCompletableFuture().join();
+                    InetSocketAddress addr = connection.getRedisClient().getAddr();
+                    Role role = Role.valueOf(r.get(ROLE_KEY));
+                    if (Role.master.equals(role)) {
+                        InetSocketAddress master = currentMaster.get();
+                        if (master.equals(addr)) {
+                            log.debug("Current master {} unchanged", master);
+                            return CompletableFuture.completedFuture(null);
+                        } else if (currentMaster.compareAndSet(master, addr)) {
+                            CompletableFuture<RedisClient> changeFuture = changeMaster(singleSlotRange.getStartSlot(), uri);
+                            return changeFuture.exceptionally(e -> {
+                                    log.error("Unable to change master to " + addr, e);
+                                    currentMaster.compareAndSet(addr, master);
+                                    return null;
+                            });
+                        }
+                    } else if (!config.checkSkipSlavesInit()) {
+                        CompletableFuture<Void> f = slaveUp(addr, uri);
+                        slaveIPs.add(addr);
+                        return f.thenApply(re -> null);
+                    }
+                    return CompletableFuture.completedFuture(null);
+                })
+                .whenComplete((r, ex) -> {
+                    if (ex != null) {
+                        log.error(ex.getMessage(), ex);
                     }
                     latch.countDown();
-                } else if (!config.checkSkipSlavesInit()) {
-                    CompletableFuture<Void> f = slaveUp(addr, uri);
-                    slaveIPs.add(addr);
-                    f.whenComplete((res, e) -> {
-                        latch.countDown();
-                    });
-                }
-            });
-        });
+                });
     }
 
     private CompletableFuture<Void> slaveUp(InetSocketAddress address, RedisURI uri) {