Redis Lettuce連接redis集群實現過程詳細講解

前言

Lettuce連接redis集群使用的都是集群專用類,像RedisClusterClient、StatefulRedisClusterConnection、RedisAdvancedClusterCommands、StatefulRedisClusterPubSubConnection等等;

Lettuce對rediscluster的支持:

  • 支持所有Cluster命令;
  • 基於鍵哈希槽的路由節點;
  • 對集群命令高級抽象;
  • 在多個集群節點上執行命令;
  • 處理MOVED和ASK重定向;
  • 通過槽位和ip端口直接連接集群節點;
  • SSL和身份驗證;
  • 定期和自適應集群拓撲更新;
  • 發佈訂閱;

啟動時隻需至少一個可以連接的集群節點就可以,能夠自動拓撲出集群全部節點;也可以使用ReadFrom設置讀取數據來源,跟主從模式一樣;

雖然redis本身的多鍵命令要求key必須都在同一個槽位,但Lettuce對一部分命令多瞭優化,可以對多鍵命令進行跨槽位執行,通過將對不同槽位鍵的操作命令分解為多條命令,單個命令以fork/join方式並發運行,最後將結果合並返回;

可以跨槽位的命令有

  • DEL:刪除鍵,返回刪除數量;
  • EXISTS:統計跨槽位的存在的鍵的數量;
  • MGET:獲取所有給定鍵的值,順序按照鍵的順序返回;
  • MSET:批量保存鍵值對,總是返回OK;
  • TOUCH:改變給定鍵的最後訪問時間,返回改變的鍵的數量;
  • UNLINK:刪除鍵並在另一個不同的線程中回收內存,返回刪除數量;

提供跨槽位命令的api:RedisAdvancedClusterCommands、RedisAdvancedClusterAsyncCommands、RedisAdvancedClusterReactiveCommands;

可以在多個集群節點上執行的命令有

  • CLIENT SETNAME:在所有已知的集群節點上設置客戶端的名稱,總是返回OK;
  • KEYS:返回所有master上存儲的key;
  • DBSIZE:返回所有master上存儲的key的數量;
  • FLUSHALL:清空master上的所有數據,總是返回OK;
  • FLUSHDB:清空master上的所有數據,總是返回OK;
  • RANDOMKEY:從隨機master上返回隨機的key;
  • SCAN:根據ReadFrom設置掃描整個集群的鍵空間;
  • SCRIPT FLUSH:從所有的集群節點腳本緩存中刪除所有腳本;
  • SCRIPT LOAD:在所有的集群節點上加載lua腳本;
  • SCRIPT KILL:在所有集群節點上殺死腳本;(即使腳本沒有運行調用也不會失敗)
  • SHUTDOWN:將數據集同步保存到磁盤,然後關閉集群所有節點;

關於發佈訂閱

普通用戶空間的發佈訂閱,redis集群會發送到每個節點,發佈者和訂閱者不需要在同一個節點,普通訂閱發佈消息可以在集群拓撲改變時重新連接。對於鍵空間事件,隻會發到自己的節點,不會擴散到其他節點,要訂閱鍵空間事件可以去適當的多個節點上訂閱,或者使用RedisClusterClient消息傳播和NodeSelectionAPI獲得一個托管連接集合;

註意:由於主從同步,鍵會被復制到多個從節點上,特別是鍵過期事件,會在主從節點上都產生過期事件,如果訂閱從節點,可能會收到多條相同的過期事件;訂閱是通過NodeSelectionAPI或者單個節點調用subscribe(…)發出的,訂閱對於新增的節點無效;

測試Demo:(redis版本7.0.2,Lettuce版本6.1.8)

集群節點:虛擬機 192.168.1.31,端口 9001-9006,集群節點已設置notify-keyspace-events AK;

package testlettuce;
import java.time.Duration;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import io.lettuce.core.ClientOptions.DisconnectedBehavior;
import io.lettuce.core.KeyScanCursor;
import io.lettuce.core.KeyValue;
import io.lettuce.core.ReadFrom;
import io.lettuce.core.RedisURI;
import io.lettuce.core.ScanCursor;
import io.lettuce.core.SocketOptions;
import io.lettuce.core.SslOptions;
import io.lettuce.core.TimeoutOptions;
import io.lettuce.core.cluster.ClusterClientOptions;
import io.lettuce.core.cluster.ClusterTopologyRefreshOptions;
import io.lettuce.core.cluster.RedisClusterClient;
import io.lettuce.core.cluster.api.StatefulRedisClusterConnection;
import io.lettuce.core.cluster.api.sync.Executions;
import io.lettuce.core.cluster.api.sync.NodeSelection;
import io.lettuce.core.cluster.api.sync.NodeSelectionCommands;
import io.lettuce.core.cluster.api.sync.RedisAdvancedClusterCommands;
import io.lettuce.core.cluster.pubsub.StatefulRedisClusterPubSubConnection;
import io.lettuce.core.cluster.pubsub.api.async.NodeSelectionPubSubAsyncCommands;
import io.lettuce.core.cluster.pubsub.api.async.PubSubAsyncNodeSelection;
import io.lettuce.core.cluster.pubsub.api.reactive.RedisClusterPubSubReactiveCommands;
import io.lettuce.core.protocol.DecodeBufferPolicies;
import io.lettuce.core.protocol.ProtocolVersion;
import io.lettuce.core.pubsub.RedisPubSubListener;
import io.lettuce.core.pubsub.api.async.RedisPubSubAsyncCommands;
public class TestLettuceCluster {
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		List<RedisURI> nodeList = new ArrayList<>();
		nodeList.add(RedisURI.builder().withHost("192.168.1.31").withPort(9001).withAuthentication("default", "123456").build());
		nodeList.add(RedisURI.builder().withHost("192.168.1.31").withPort(9002).withAuthentication("default", "123456").build());
		nodeList.add(RedisURI.builder().withHost("192.168.1.31").withPort(9003).withAuthentication("default", "123456").build());
		nodeList.add(RedisURI.builder().withHost("192.168.1.31").withPort(9004).withAuthentication("default", "123456").build());
		nodeList.add(RedisURI.builder().withHost("192.168.1.31").withPort(9005).withAuthentication("default", "123456").build());
		nodeList.add(RedisURI.builder().withHost("192.168.1.31").withPort(9006).withAuthentication("default", "123456").build());
		RedisClusterClient clusterClient = RedisClusterClient.create(nodeList);
		ClusterTopologyRefreshOptions clusterTopologyRefreshOptions = ClusterTopologyRefreshOptions.builder()
	            .adaptiveRefreshTriggersTimeout(Duration.ofSeconds(5L))//設置自適應拓撲刷新超時,每次超時刷新一次,默認30s;
	            .closeStaleConnections(false)//刷新拓撲時是否關閉失效連接,默認true,isPeriodicRefreshEnabled()為true時生效;
	            .dynamicRefreshSources(true)//從拓撲中發現新節點,並將新節點也作為拓撲的源節點,動態刷新可以發現全部節點並計算每個客戶端的數量,設置false則隻有初始節點為源和計算客戶端數量;
	            .enableAllAdaptiveRefreshTriggers()//啟用全部觸發器自適應刷新拓撲,默認關閉;
	            .enablePeriodicRefresh(Duration.ofSeconds(5L))//開啟定時拓撲刷新並設置周期;
	            .refreshTriggersReconnectAttempts(3)//長連接重新連接嘗試n次才拓撲刷新
	            .build();
		ClusterClientOptions clusterClientOptions = ClusterClientOptions.builder()
				.autoReconnect(true)//在連接丟失時開啟或關閉自動重連,默認true;
				.cancelCommandsOnReconnectFailure(true)//允許在重連失敗取消排隊命令,默認false;
				.decodeBufferPolicy(DecodeBufferPolicies.always())//設置丟棄解碼緩沖區的策略,以回收內存;always:解碼後丟棄,最大內存效率;alwaysSome:解碼後丟棄一部分;ratio(n)基於比率丟棄,n/(1+n),通常用1-10對應50%-90%;
				.disconnectedBehavior(DisconnectedBehavior.DEFAULT)//設置連接斷開時命令的調用行為,默認啟用重連;DEFAULT:啟用時重連中接收命令,禁用時重連中拒絕命令;ACCEPT_COMMANDS:重連中接收命令;REJECT_COMMANDS:重連中拒絕命令;
//				.maxRedirects(5)//當鍵從一個節點遷移到另一個節點,集群重定向次數,默認5;
//				.nodeFilter(nodeFilter)//設置節點過濾器
//				.pingBeforeActivateConnection(true)//激活連接前設置PING,默認true;
//				.protocolVersion(ProtocolVersion.RESP3)//設置協議版本,默認RESP3;
//				.publishOnScheduler(false)//使用專用的調度器發出響應信號,默認false,啟用時數據信號將使用服務的多線程發出;
//				.requestQueueSize(requestQueueSize)//設置每個連接請求隊列大小;
//				.scriptCharset(scriptCharset)//設置Lua腳本編碼為byte[]的字符集,默認StandardCharsets.UTF_8;
//				.socketOptions(SocketOptions.builder().connectTimeout(Duration.ofSeconds(10)).keepAlive(true).tcpNoDelay(true).build())//設置低級套接字的屬性
//				.sslOptions(SslOptions.builder().build())//設置ssl屬性
//				.suspendReconnectOnProtocolFailure(false)//當重新連接遇到協議失敗時暫停重新連接(SSL驗證,連接失敗前PING),默認值為false;
//				.timeoutOptions(TimeoutOptions.enabled(Duration.ofSeconds(10)))//設置超時來取消和終止命令;
				.topologyRefreshOptions(clusterTopologyRefreshOptions)//設置拓撲更新設置
				.validateClusterNodeMembership(true)//在允許連接到集群節點之前,驗證集群節點成員關系,默認值為true;
				.build();
		clusterClient.setDefaultTimeout(Duration.ofSeconds(5L));
		clusterClient.setOptions(clusterClientOptions);
		StatefulRedisClusterConnection<String, String> clusterConn = clusterClient.connect();
		clusterConn.setReadFrom(ReadFrom.ANY);//設置從哪些節點讀取數據;
		RedisAdvancedClusterCommands<String, String> clusterCmd = clusterConn.sync();
		clusterCmd.set("a", "A");
		clusterCmd.set("b", "B");
		clusterCmd.set("c", "C");
		clusterCmd.set("d", "D"); 
		System.out.println("get a=" + clusterCmd.get("a"));
		System.out.println("get b=" + clusterCmd.get("b"));
		System.out.println("get c=" + clusterCmd.get("c"));
		System.out.println("get d=" + clusterCmd.get("d"));
		//跨槽位命令
		Map<String, String> kvmap = new HashMap<>();
		kvmap.put("a", "AA");
		kvmap.put("b", "BB");
		kvmap.put("c", "CC");
		kvmap.put("d", "DD");
		clusterCmd.mset(kvmap);//Lettuce做瞭優化,支持一些命令的跨槽位命令;
		System.out.println("Lettuce mget:" + clusterCmd.mget("a", "b", "c", "d"));
		//選定部分節點操作
		NodeSelection<String, String> replicas = clusterCmd.replicas();
		NodeSelectionCommands<String, String> replicaseCmd = replicas.commands();
		Executions<KeyScanCursor<String>> executions = replicaseCmd.scan(ScanCursor.INITIAL);
		executions.forEach(s -> {System.out.println(s.getKeys());});
		//訂閱發佈消息
		StatefulRedisClusterPubSubConnection<String, String> pubSubConn = clusterClient.connectPubSub();
		pubSubConn.addListener(new RedisPubSubListener<String, String>() {
			@Override
			public void message(String channel, String message) {
				System.out.println("[message]ch:" + channel + ",msg:" + message);
			}
			@Override
			public void message(String pattern, String channel, String message) {
			}
			@Override
			public void subscribed(String channel, long count) {
				System.out.println("[subscribed]ch:" + channel);
			}
			@Override
			public void psubscribed(String pattern, long count) {
			}
			@Override
			public void unsubscribed(String channel, long count) {
			}
			@Override
			public void punsubscribed(String pattern, long count) {
			}
		});
		pubSubConn.sync().subscribe("TEST_Ch");//(回調內部使用阻塞調用或者lettuce同步api調用,需使用異步訂閱)
		clusterCmd.publish("TEST_Ch", "MSGMSGMSG");
		//響應式訂閱,可以監聽ChannelMessage和PatternMessage,使用鏈式過濾處理計算等操作
		RedisClusterPubSubReactiveCommands<String, String> pubsubReactive = pubSubConn.reactive();
		pubsubReactive.subscribe("TEST_Ch2").subscribe();
		pubsubReactive.observeChannels()
			.filter(chmsg -> {return chmsg.getMessage().contains("tom");})
			.doOnNext(chmsg -> {System.out.println("<tom>" + chmsg.getChannel() + ">>" + chmsg.getMessage());})
			.subscribe();
		clusterCmd.publish("TEST_Ch2", "send to jerry");
		clusterCmd.publish("TEST_Ch", "tom MSG");
		clusterCmd.publish("TEST_Ch2", "this is tom");
		//keySpaceEvent事件
		StatefulRedisClusterPubSubConnection<String, String> clusterPubSubConn = clusterClient.connectPubSub();
		clusterPubSubConn.setNodeMessagePropagation(true);//啟用禁用節點消息傳播到該listener,例如隻能在本節點通知的鍵事件通知;
		RedisPubSubListener<String, String> listener  = new RedisPubSubListener<String, String>() {
			@Override
			public void unsubscribed(String channel, long count) {
				System.out.println("unsubscribed_ch:" + channel);
			}
			@Override
			public void subscribed(String channel, long count) {
				System.out.println("subscribed_ch:" + channel);
			}
			@Override
			public void punsubscribed(String pattern, long count) {
				System.out.println("punsubscribed_pattern:" + pattern);
			}
			@Override
			public void psubscribed(String pattern, long count) {
				System.out.println("psubscribed_pattern:" + pattern);
			}
			@Override
			public void message(String pattern, String channel, String message) {
				System.out.println("message_pattern:" + pattern + " ch:" + channel + " msg:" + message);
			}
			@Override
			public void message(String channel, String message) {
				System.out.println("message_ch:" + channel + " msg:" + message);
			}
		};
		clusterPubSubConn.addListener(listener);
		PubSubAsyncNodeSelection<String, String> allPubSubAsyncNodeSelection = clusterPubSubConn.async().all();
		NodeSelectionPubSubAsyncCommands<String, String> pubsubAsyncCmd = allPubSubAsyncNodeSelection.commands();
		clusterCmd.setex("a", 1, "A");
		pubsubAsyncCmd.psubscribe("[email protected]__:*");
		try {
			Thread.sleep(3000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		System.out.println("end");
	}
}

運行結果:

另外,還有一個cluster專用的Listener:RedisClusterPubSubListener,可以從listener裡獲得發佈消息的節點信息:

RedisClusterPubSubListener<String, String> clusterListener = new RedisClusterPubSubListener<String, String>() {
			@Override
			public void message(RedisClusterNode node, String channel, String message) {
			}
			@Override
			public void message(RedisClusterNode node, String pattern, String channel, String message) {
			}
			@Override
			public void subscribed(RedisClusterNode node, String channel, long count) {
			}
			@Override
			public void psubscribed(RedisClusterNode node, String pattern, long count) {
			}
			@Override
			public void unsubscribed(RedisClusterNode node, String channel, long count) {
			}
			@Override
			public void punsubscribed(RedisClusterNode node, String pattern, long count) {
			}
		};

到此這篇關於Redis Lettuce連接redis集群實現過程詳細講解的文章就介紹到這瞭,更多相關Redis Lettuce連接redis集群內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet!

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