Reuse connections of the same address in ZooKeeper data-source (#788)

* Fix the problem that too many connections (zkClient) are established

sentinel-extension/sentinel-datasource-zookeeper/src/main/java/com/alibaba/csp/sentinel/datasource/zookeeper/ZookeeperDataSource.java

@@ -1,17 +1,10 @@
 package com.alibaba.csp.sentinel.datasource.zookeeper;
 
-import java.util.List;
-import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
-
 import com.alibaba.csp.sentinel.concurrent.NamedThreadFactory;
 import com.alibaba.csp.sentinel.datasource.AbstractDataSource;
 import com.alibaba.csp.sentinel.datasource.Converter;
 import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.util.StringUtil;
-
 import org.apache.curator.framework.AuthInfo;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.framework.CuratorFrameworkFactory;
@@ -19,8 +12,15 @@ import org.apache.curator.framework.recipes.cache.ChildData;
 import org.apache.curator.framework.recipes.cache.NodeCache;
 import org.apache.curator.framework.recipes.cache.NodeCacheListener;
 import org.apache.curator.retry.ExponentialBackoffRetry;
-import org.apache.zookeeper.CreateMode;
+
-import org.apache.zookeeper.data.Stat;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 
 /**
  * A read-only {@code DataSource} with ZooKeeper backend.
@@ -32,6 +32,10 @@ public class ZookeeperDataSource<T> extends AbstractDataSource<String, T> {
     private static final int RETRY_TIMES = 3;
     private static final int SLEEP_TIME = 1000;
 
+    private static volatile Map<String, CuratorFramework> zkClientMap = new HashMap<>();
+    private static final Object lock = new Object();
+
+
     private final ExecutorService pool = new ThreadPoolExecutor(1, 1, 0, TimeUnit.MILLISECONDS,
             new ArrayBlockingQueue<Runnable>(1), new NamedThreadFactory("sentinel-zookeeper-ds-update"),
             new ThreadPoolExecutor.DiscardOldestPolicy());
@@ -116,16 +120,33 @@ public class ZookeeperDataSource<T> extends AbstractDataSource<String, T> {
                 }
             };
 
-            if (authInfos == null || authInfos.size() == 0) {
+            String zkKey = getZkKey(serverAddr, authInfos);
-                this.zkClient = CuratorFrameworkFactory.newClient(serverAddr, new ExponentialBackoffRetry(SLEEP_TIME, RETRY_TIMES));
+            if (zkClientMap.containsKey(zkKey)) {
+                this.zkClient = zkClientMap.get(zkKey);
             } else {
-                this.zkClient = CuratorFrameworkFactory.builder().
+                synchronized (lock) {
+                    if (!zkClientMap.containsKey(zkKey)) {
+                        CuratorFramework zc = null;
+                        if (authInfos == null || authInfos.size() == 0) {
+                            zc = CuratorFrameworkFactory.newClient(serverAddr, new ExponentialBackoffRetry(SLEEP_TIME, RETRY_TIMES));
+                        } else {
+                            zc = CuratorFrameworkFactory.builder().
                                     connectString(serverAddr).
                                     retryPolicy(new ExponentialBackoffRetry(SLEEP_TIME, RETRY_TIMES)).
                                     authorization(authInfos).
                                     build();
                         }
+                        this.zkClient = zc;
                         this.zkClient.start();
+                        Map<String, CuratorFramework> newZkClientMap = new HashMap<>(zkClientMap.size());
+                        newZkClientMap.putAll(zkClientMap);
+                        newZkClientMap.put(zkKey, zc);
+                        zkClientMap = newZkClientMap;
+                    } else {
+                        this.zkClient = zkClientMap.get(zkKey);
+                    }
+                }
+            }
 
             this.nodeCache = new NodeCache(this.zkClient, this.path);
             this.nodeCache.getListenable().addListener(this.listener, this.pool);
@@ -165,4 +186,31 @@ public class ZookeeperDataSource<T> extends AbstractDataSource<String, T> {
     private String getPath(String groupId, String dataId) {
         return String.format("/%s/%s", groupId, dataId);
     }
+
+    private String getZkKey(final String serverAddr, final List<AuthInfo> authInfos) {
+        if (authInfos == null || authInfos.size() == 0) {
+            return serverAddr;
+        }
+        StringBuilder builder = new StringBuilder(64);
+        builder.append(serverAddr).append(getAuthInfosKey(authInfos));
+        return builder.toString();
+    }
+
+    private String getAuthInfosKey(List<AuthInfo> authInfos) {
+        StringBuilder builder = new StringBuilder(32);
+        for (AuthInfo authInfo : authInfos) {
+            if (authInfo == null) {
+                builder.append("{}");
+            } else {
+                builder.append("{" + "sc=" + authInfo.getScheme() + ",au=" + Arrays.toString(authInfo.getAuth()) + "}");
+            }
+        }
+        return builder.toString();
+    }
+
+    protected CuratorFramework getZkClient() {
+        return this.zkClient;
+    }
+
+
 }

sentinel-extension/sentinel-datasource-zookeeper/src/test/java/com/alibaba/csp/sentinel/datasource/zookeeper/ZookeeperDataSourceTest.java

@@ -3,6 +3,7 @@ package com.alibaba.csp.sentinel.datasource.zookeeper;
 import com.alibaba.csp.sentinel.datasource.Converter;
 import com.alibaba.csp.sentinel.datasource.ReadableDataSource;
 import com.alibaba.csp.sentinel.slots.block.RuleConstant;
+import com.alibaba.csp.sentinel.slots.block.degrade.DegradeRule;
 import com.alibaba.csp.sentinel.slots.block.flow.FlowRule;
 import com.alibaba.csp.sentinel.slots.block.flow.FlowRuleManager;
 import com.alibaba.fastjson.JSON;
@@ -18,6 +19,7 @@ import org.apache.zookeeper.data.ACL;
 import org.apache.zookeeper.data.Id;
 import org.apache.zookeeper.data.Stat;
 import org.apache.zookeeper.server.auth.DigestAuthenticationProvider;
+import org.junit.Assert;
 import org.junit.Test;
 
 import java.util.Collections;
@@ -46,7 +48,8 @@ public class ZookeeperDataSourceTest {
                 new Converter<String, List<FlowRule>>() {
                     @Override
                     public List<FlowRule> convert(String source) {
-                    return JSON.parseObject(source, new TypeReference<List<FlowRule>>() {});
+                        return JSON.parseObject(source, new TypeReference<List<FlowRule>>() {
+                        });
                     }
                 });
         FlowRuleManager.register2Property(flowRuleDataSource.getProperty());
@@ -67,6 +70,9 @@ public class ZookeeperDataSourceTest {
         server.stop();
     }
 
+
+
+
     @Test
     public void testZooKeeperDataSourceAuthorization() throws Exception {
         TestingServer server = new TestingServer(21812);
@@ -142,4 +148,77 @@ public class ZookeeperDataSourceTest {
         }
         assertTrue(exists);
     }
+
+
+    /**
+     * Test whether different dataSources can share the same zkClient when the connection parameters are the same.
+     * @throws Exception
+     */
+    @Test
+    public void testZooKeeperDataSourceSameZkClient() throws Exception {
+        TestingServer server = new TestingServer(21813);
+        server.start();
+
+        final String remoteAddress = server.getConnectString();
+        final String flowPath = "/sentinel-zk-ds-demo/flow-HK";
+        final String degradePath = "/sentinel-zk-ds-demo/degrade-HK";
+
+
+        ZookeeperDataSource<List<FlowRule>> flowRuleZkDataSource = new ZookeeperDataSource<>(remoteAddress, flowPath,
+                new Converter<String, List<FlowRule>>() {
+                    @Override
+                    public List<FlowRule> convert(String source) {
+                        return JSON.parseObject(source, new TypeReference<List<FlowRule>>() {
+                        });
+                    }
+                });
+        ZookeeperDataSource<List<DegradeRule>> degradeRuleZkDataSource = new ZookeeperDataSource<>(remoteAddress, degradePath,
+                new Converter<String, List<DegradeRule>>() {
+                    @Override
+                    public List<DegradeRule> convert(String source) {
+                        return JSON.parseObject(source, new TypeReference<List<DegradeRule>>() {
+                        });
+                    }
+                });
+
+
+        Assert.assertTrue(flowRuleZkDataSource.getZkClient() == degradeRuleZkDataSource.getZkClient());
+
+
+        final String groupId = "sentinel-zk-ds-demo";
+        final String flowDataId = "flow-HK";
+        final String degradeDataId = "degrade-HK";
+        final String scheme = "digest";
+        final String auth = "root:123456";
+        AuthInfo authInfo = new AuthInfo(scheme, auth.getBytes());
+        List<AuthInfo> authInfoList = Collections.singletonList(authInfo);
+
+
+        ZookeeperDataSource<List<FlowRule>> flowRuleZkAutoDataSource = new ZookeeperDataSource<List<FlowRule>>(remoteAddress,
+                authInfoList, groupId, flowDataId,
+                new Converter<String, List<FlowRule>>() {
+                    @Override
+                    public List<FlowRule> convert(String source) {
+                        return JSON.parseObject(source, new TypeReference<List<FlowRule>>() {
+                        });
+                    }
+                });
+
+        ZookeeperDataSource<List<DegradeRule>> degradeRuleZkAutoDataSource = new ZookeeperDataSource<List<DegradeRule>>(remoteAddress,
+                authInfoList, groupId, degradeDataId,
+                new Converter<String, List<DegradeRule>>() {
+                    @Override
+                    public List<DegradeRule> convert(String source) {
+                        return JSON.parseObject(source, new TypeReference<List<DegradeRule>>() {
+                        });
+                    }
+                });
+
+        Assert.assertTrue(flowRuleZkAutoDataSource.getZkClient() == degradeRuleZkAutoDataSource.getZkClient());
+
+        server.stop();
+    }
+
+
+
 }