[GitHub] [incubator-livy] runzhiwang commented on a change in pull request #267: [LIVY-732][SERVER] A common zookeeper wrapper utility

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runzhiwang commented on a change in pull request #267: [LIVY-732][SERVER] A common zookeeper wrapper utility
URL: https://github.com/apache/incubator-livy/pull/267#discussion_r363198595
 
 

 ##########
 File path: server/src/main/scala/org/apache/livy/server/recovery/ZooKeeperManager.scala
 ##########
 @@ -0,0 +1,118 @@
+/*
+ * 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.livy.server.recovery
+
+import scala.collection.JavaConverters._
+import scala.reflect.ClassTag
+
+import org.apache.curator.framework.api.UnhandledErrorListener
+import org.apache.curator.framework.CuratorFramework
+import org.apache.curator.framework.CuratorFrameworkFactory
+import org.apache.curator.retry.RetryNTimes
+import org.apache.zookeeper.KeeperException.NoNodeException
+
+import org.apache.livy.LivyConf
+import org.apache.livy.Logging
+
+class ZooKeeperManager(
+    livyConf: LivyConf,
+    mockCuratorClient: Option[CuratorFramework] = None)
+  extends JsonMapper with Logging {
+
+  def this(livyConf: LivyConf) {
+    this(livyConf, None)
+  }
+
+  private val zkAddress = Option(livyConf.get(LivyConf.ZOOKEEPER_URL)).
+    orElse(Option(livyConf.get(LivyConf.RECOVERY_STATE_STORE_URL))).
+    map(_.trim).orNull
+
+  require(zkAddress != null && !zkAddress.isEmpty,
+    s"Please config ${LivyConf.ZOOKEEPER_URL.key}.")
+
+  private val retryValue = Option(livyConf.get(LivyConf.ZK_RETRY_POLICY)).
+    orElse(Option(livyConf.get(LivyConf.RECOVERY_ZK_STATE_STORE_RETRY_POLICY))).
+    map(_.trim).orNull
+
+  require(retryValue != null && !retryValue.isEmpty,
+    s"Please config ${LivyConf.ZK_RETRY_POLICY.key}.")
+
+  // a regex to match patterns like "m, n" where m and n both are integer values
+  private val retryPattern = """\s*(\d+)\s*,\s*(\d+)\s*""".r
+  private[recovery] val retryPolicy = retryValue match {
+    case retryPattern(n, sleepMs) => new RetryNTimes(n.toInt, sleepMs.toInt)
+    case _ => throw new IllegalArgumentException(
+      s"contains bad value: $retryValue. " +
+        "Correct format is <max retry count>,<sleep ms between retry>. e.g. 5,100")
+  }
+
+  private val curatorClient = mockCuratorClient.getOrElse {
+    CuratorFrameworkFactory.newClient(zkAddress, retryPolicy)
+  }
+
+  curatorClient.getUnhandledErrorListenable().addListener(new UnhandledErrorListener {
+    def unhandledError(message: String, e: Throwable): Unit = {
+      error(s"Fatal Zookeeper error: ${message}.", e)
+    }
+  })
+
+  def start(): Unit = {
+    curatorClient.start()
+  }
+
+  def stop(): Unit = {
+    curatorClient.close()
+  }
+
+  // TODO Make sure ZK path has proper secure permissions so that other users cannot read its
+  // contents.
+
 
 Review comment:
   updated

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