From f2a98193d467c262cc75f6da23590405e3503cbb Mon Sep 17 00:00:00 2001
From: pengys5 <8082209@qq.com>
Date: Tue, 1 Aug 2017 20:14:47 +0800
Subject: [PATCH] Fixed #327. When collector server restart at short intervals
 that zookeeper will not find remove this server path. But in another
 situation, there was a same address server has been running, the restart
 server could not remove this path and recreate it. So when this situation
 happened, throw exception to stop this restart server.

---
 .../cluster/ClusterNodeExistException.java      | 17 +++++++++++++++++
 .../cluster/zookeeper/ClusterZKDataMonitor.java |  7 ++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/ClusterNodeExistException.java

diff --git a/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/ClusterNodeExistException.java b/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/ClusterNodeExistException.java
new file mode 100644
index 000000000..d449920ea
--- /dev/null
+++ b/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/ClusterNodeExistException.java
@@ -0,0 +1,17 @@
+package org.skywalking.apm.collector.cluster;
+
+import org.skywalking.apm.collector.core.client.ClientException;
+
+/**
+ * @author pengys5
+ */
+public class ClusterNodeExistException extends ClientException {
+
+    public ClusterNodeExistException(String message) {
+        super(message);
+    }
+
+    public ClusterNodeExistException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}
diff --git a/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/zookeeper/ClusterZKDataMonitor.java b/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/zookeeper/ClusterZKDataMonitor.java
index 7e973716a..a2e6c862f 100644
--- a/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/zookeeper/ClusterZKDataMonitor.java
+++ b/apm-collector/apm-collector-cluster/src/main/java/org/skywalking/apm/collector/cluster/zookeeper/ClusterZKDataMonitor.java
@@ -10,6 +10,7 @@ import org.apache.zookeeper.ZooDefs;
 import org.skywalking.apm.collector.client.zookeeper.ZookeeperClient;
 import org.skywalking.apm.collector.client.zookeeper.ZookeeperClientException;
 import org.skywalking.apm.collector.client.zookeeper.util.PathUtils;
+import org.skywalking.apm.collector.cluster.ClusterNodeExistException;
 import org.skywalking.apm.collector.core.client.Client;
 import org.skywalking.apm.collector.core.client.ClientException;
 import org.skywalking.apm.collector.core.client.DataMonitor;
@@ -74,7 +75,11 @@ public class ClusterZKDataMonitor implements DataMonitor, Watcher {
         String serverPath = path + "/" + value.getHostPort();
         listener.addAddress(value.getHostPort() + contextPath);
 
-        setData(serverPath, contextPath);
+        if (client.exists(serverPath, false) == null) {
+            setData(serverPath, contextPath);
+        } else {
+            throw new ClusterNodeExistException("current address: " + value.getHostPort() + " has been registered, check the host and port configuration or wait a moment.");
+        }
     }
 
     @Override public ClusterDataListener getListener(String path) {