HBASE-26614 Refactor code related to "dump"ing ZK nodes (apache#3969)

The code starting at `ZKUtil.dump(ZKWatcher)` is a small mess – it has cyclic dependencies woven
through itself, `ZKWatcher` and `RecoverableZooKeeper`. It also initializes a static variable in
`ZKUtil` through the factory for `RecoverableZooKeeper` instances. Let's decouple and clean it
up.

Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Josh Elser <elserj@apache.org>

hbase-it/src/test/java/org/apache/hadoop/hbase/test/IntegrationTestZKAndFSPermissions.java

@@ -35,7 +35,6 @@
 import org.apache.hadoop.hbase.util.AbstractHBaseTool;
 import org.apache.hadoop.hbase.util.CommonFSUtils;
 import org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper;
-import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
 import org.apache.hadoop.hbase.zookeeper.ZNodePaths;
 import org.apache.hadoop.util.ToolRunner;
@@ -142,7 +141,7 @@ protected int doWork() throws Exception {
   private void testZNodeACLs() throws IOException, KeeperException, InterruptedException {
 
     ZKWatcher watcher = new ZKWatcher(conf, "IntegrationTestZnodeACLs", null);
-    RecoverableZooKeeper zk = ZKUtil.connect(this.conf, watcher);
+    RecoverableZooKeeper zk = RecoverableZooKeeper.connect(this.conf, watcher);
 
     String baseZNode = watcher.getZNodePaths().baseZNode;
 

hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/DumpReplicationQueues.java

@@ -48,6 +48,7 @@
 import org.apache.hadoop.hbase.replication.ReplicationQueueStorage;
 import org.apache.hadoop.hbase.replication.ReplicationStorageFactory;
 import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
+import org.apache.hadoop.hbase.zookeeper.ZKDump;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
 import org.apache.hadoop.util.Tool;
@@ -241,7 +242,7 @@ private int dumpReplicationQueues(DumpOptions opts) throws Exception {
       } else {
         // use ZK instead
         System.out.print("Dumping replication znodes via ZooKeeper:");
-        System.out.println(ZKUtil.getReplicationZnodesDump(zkw));
+        System.out.println(ZKDump.getReplicationZnodesDump(zkw));
       }
       return (0);
     } catch (IOException e) {

hbase-server/src/main/resources/hbase-webapps/master/zk.jsp

@@ -19,9 +19,9 @@
 --%>
 <%@ page contentType="text/html;charset=UTF-8"
   import="org.apache.commons.lang3.StringEscapeUtils"
-  import="org.apache.hadoop.hbase.zookeeper.ZKUtil"
-  import="org.apache.hadoop.hbase.zookeeper.ZKWatcher"
   import="org.apache.hadoop.hbase.master.HMaster"
+  import="org.apache.hadoop.hbase.zookeeper.ZKDump"
+  import="org.apache.hadoop.hbase.zookeeper.ZKWatcher"
 %>
 <%
   HMaster master = (HMaster)getServletContext().getAttribute(HMaster.MASTER);
@@ -38,7 +38,7 @@
             </div>
             <div class="row">
                 <div class="span12">
-                    <pre><%= StringEscapeUtils.escapeHtml4(ZKUtil.dump(watcher).trim()) %></pre>
+                    <pre><%= StringEscapeUtils.escapeHtml4(ZKDump.dump(watcher).trim()) %></pre>
                 </div>
             </div>
         </div>

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

@@ -44,7 +44,6 @@
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.zookeeper.MiniZooKeeperCluster;
 import org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper;
-import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
 
 import org.junit.After;
@@ -282,7 +281,7 @@ public void testBulkLoadReplicationActiveActive() throws Exception {
     // Verify hfile-refs for 1:ns_peer1, expect is empty
     MiniZooKeeperCluster zkCluster = UTIL1.getZkCluster();
     ZKWatcher watcher = new ZKWatcher(UTIL1.getConfiguration(), "TestZnodeHFiles-refs", null);
-    RecoverableZooKeeper zk = ZKUtil.connect(UTIL1.getConfiguration(), watcher);
+    RecoverableZooKeeper zk = RecoverableZooKeeper.connect(UTIL1.getConfiguration(), watcher);
     ZKReplicationQueueStorage replicationQueueStorage =
         new ZKReplicationQueueStorage(watcher, UTIL1.getConfiguration());
     Set<String> hfiles = replicationQueueStorage.getAllHFileRefs();

hbase-shell/src/main/ruby/hbase/admin.rb

@@ -452,7 +452,7 @@ def zk_dump
       )
       zk = @zk_wrapper.getRecoverableZooKeeper.getZooKeeper
       @zk_main = org.apache.zookeeper.ZooKeeperMain.new(zk)
-      org.apache.hadoop.hbase.zookeeper.ZKUtil.dump(@zk_wrapper)
+      org.apache.hadoop.hbase.zookeeper.ZKDump.dump(@zk_wrapper)
     end
 
     #----------------------------------------------------------------------------------------------

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/MetaTableLocator.java

@@ -58,7 +58,7 @@ private MetaTableLocator() {
    * @return server name or null if we failed to get the data.
    */
   @RestrictedApi(explanation = "Should only be called in tests or ZKUtil", link = "",
-    allowedOnPath = ".*/src/test/.*|.*/ZKUtil\\.java")
+    allowedOnPath = ".*/src/test/.*|.*/ZKDump\\.java")
   public static ServerName getMetaRegionLocation(final ZKWatcher zkw) {
     try {
       RegionState state = getMetaRegionState(zkw);
@@ -75,7 +75,7 @@ public static ServerName getMetaRegionLocation(final ZKWatcher zkw) {
    * @return server name
    */
   @RestrictedApi(explanation = "Should only be called in self or ZKUtil", link = "",
-    allowedOnPath = ".*(MetaTableLocator|ZKUtil)\\.java")
+    allowedOnPath = ".*(MetaTableLocator|ZKDump)\\.java")
   public static ServerName getMetaRegionLocation(final ZKWatcher zkw, int replicaId) {
     try {
       RegionState state = getMetaRegionState(zkw, replicaId);

hbase-zookeeper/src/main/java/org/apache/hadoop/hbase/zookeeper/RecoverableZooKeeper.java

@@ -25,6 +25,8 @@
 import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.trace.TraceUtil;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
@@ -84,6 +86,57 @@ public class RecoverableZooKeeper {
   private final String quorumServers;
   private final int maxMultiSize;
 
+  /**
+   * See {@link #connect(Configuration, String, Watcher, String)}
+   */
+  public static RecoverableZooKeeper connect(Configuration conf, Watcher watcher)
+    throws IOException {
+    String ensemble = ZKConfig.getZKQuorumServersString(conf);
+    return connect(conf, ensemble, watcher);
+  }
+
+  /**
+   * See {@link #connect(Configuration, String, Watcher, String)}
+   */
+  public static RecoverableZooKeeper connect(Configuration conf, String ensemble,
+    Watcher watcher)
+    throws IOException {
+    return connect(conf, ensemble, watcher, null);
+  }
+
+  /**
+   * Creates a new connection to ZooKeeper, pulling settings and ensemble config
+   * from the specified configuration object using methods from {@link ZKConfig}.
+   *
+   * Sets the connection status monitoring watcher to the specified watcher.
+   *
+   * @param conf configuration to pull ensemble and other settings from
+   * @param watcher watcher to monitor connection changes
+   * @param ensemble ZooKeeper servers quorum string
+   * @param identifier value used to identify this client instance.
+   * @return connection to zookeeper
+   * @throws IOException if unable to connect to zk or config problem
+   */
+  public static RecoverableZooKeeper connect(Configuration conf, String ensemble,
+    Watcher watcher, final String identifier)
+    throws IOException {
+    if(ensemble == null) {
+      throw new IOException("Unable to determine ZooKeeper ensemble");
+    }
+    int timeout = conf.getInt(HConstants.ZK_SESSION_TIMEOUT,
+      HConstants.DEFAULT_ZK_SESSION_TIMEOUT);
+    if (LOG.isTraceEnabled()) {
+      LOG.trace("{} opening connection to ZooKeeper ensemble={}", identifier, ensemble);
+    }
+    int retry = conf.getInt("zookeeper.recovery.retry", 3);
+    int retryIntervalMillis =
+      conf.getInt("zookeeper.recovery.retry.intervalmill", 1000);
+    int maxSleepTime = conf.getInt("zookeeper.recovery.retry.maxsleeptime", 60000);
+    int multiMaxSize = conf.getInt("zookeeper.multi.max.size", 1024*1024);
+    return new RecoverableZooKeeper(ensemble, timeout, watcher,
+      retry, retryIntervalMillis, maxSleepTime, identifier, multiMaxSize);
+  }
+
   @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="DE_MIGHT_IGNORE",
       justification="None. Its always been this way.")
   public RecoverableZooKeeper(String quorumServers, int sessionTimeout,