Merge pull request #762 from chickenlj:bugfix#685_registrycache

* Optimize(AbstractRegistry) registry cache, one registry file per 'registry & application', avoid reload (#685).

* Fixed #692 optimize zookeeper operation in service export/reference process: check already exists before create

Author: chickenlj

dubbo-registry/dubbo-registry-api/src/main/java/com/alibaba/dubbo/registry/support/AbstractRegistry.java

@@ -83,7 +83,7 @@ public AbstractRegistry(URL url) {
         setUrl(url);
         // 启动文件保存定时器
         syncSaveFile = url.getParameter(Constants.REGISTRY_FILESAVE_SYNC_KEY, false);
-        String filename = url.getParameter(Constants.FILE_KEY, System.getProperty("user.home") + "/.dubbo/dubbo-registry-" + url.getHost() + ".cache");
+        String filename = url.getParameter(Constants.FILE_KEY, System.getProperty("user.home") + "/.dubbo/dubbo-registry-" + url.getParameter(Constants.APPLICATION_KEY) + "-" + url.getAddress() + ".cache");
         File file = null;
         if (ConfigUtils.isNotEmpty(filename)) {
             file = new File(filename);
@@ -149,28 +149,8 @@ public void doSaveProperties(long version) {
         if (file == null) {
             return;
         }
-        Properties newProperties = new Properties();
-        // 保存之前先读取一遍，防止多个注册中心之间冲突
-        InputStream in = null;
-        try {
-            if (file.exists()) {
-                in = new FileInputStream(file);
-                newProperties.load(in);
-            }
-        } catch (Throwable e) {
-            logger.warn("Failed to load registry store file, cause: " + e.getMessage(), e);
-        } finally {
-            if (in != null) {
-                try {
-                    in.close();
-                } catch (IOException e) {
-                    logger.warn(e.getMessage(), e);
-                }
-            }
-        }
         // 保存
         try {
-            newProperties.putAll(properties);
             File lockfile = new File(file.getAbsolutePath() + ".lock");
             if (!lockfile.exists()) {
                 lockfile.createNewFile();
@@ -190,7 +170,7 @@ public void doSaveProperties(long version) {
                         }
                         FileOutputStream outputFile = new FileOutputStream(file);
                         try {
-                            newProperties.store(outputFile, "Dubbo Registry Cache");
+                            properties.store(outputFile, "Dubbo Registry Cache");
                         } finally {
                             outputFile.close();
                         }

dubbo-remoting/dubbo-remoting-zookeeper/src/main/java/com/alibaba/dubbo/remoting/zookeeper/curator/CuratorZookeeperClient.java

@@ -88,6 +88,15 @@ public List<String> getChildren(String path) {
         }
     }
 
+    public boolean checkExists(String path) {
+        try {
+            if (client.checkExists().forPath(path) != null) {
+                return true;
+            }
+        } catch (Exception e) {
+        }
+        return false;
+    }
     public boolean isConnected() {
         return client.getZookeeperClient().isConnected();
     }

dubbo-remoting/dubbo-remoting-zookeeper/src/main/java/com/alibaba/dubbo/remoting/zookeeper/support/AbstractZookeeperClient.java

@@ -36,7 +36,10 @@ public URL getUrl() {
     public void create(String path, boolean ephemeral) {
         int i = path.lastIndexOf('/');
         if (i > 0) {
-            create(path.substring(0, i), false);
+            String parentPath = path.substring(0, i);
+            if (!checkExists(parentPath)) {
+                create(parentPath, false);
+            }
         }
         if (ephemeral) {
             createEphemeral(path);
@@ -105,6 +108,8 @@ public void close() {
 
     protected abstract void createEphemeral(String path);
 
+    protected abstract boolean checkExists(String path);
+
     protected abstract TargetChildListener createTargetChildListener(String path, ChildListener listener);
 
     protected abstract List<String> addTargetChildListener(String path, TargetChildListener listener);

dubbo-remoting/dubbo-remoting-zookeeper/src/main/java/com/alibaba/dubbo/remoting/zookeeper/zkclient/ZkclientZookeeperClient.java

@@ -68,6 +68,14 @@ public List<String> getChildren(String path) {
         }
     }
 
+    public boolean checkExists(String path) {
+        try {
+            return client.exists(path);
+        } catch (Throwable t) {
+        }
+        return false;
+    }
+
     public boolean isConnected() {
         return state == KeeperState.SyncConnected;
     }

dubbo-remoting/dubbo-remoting-zookeeper/src/test/java/com/alibaba/dubbo/remoting/zookeeper/curator/CuratorZookeeperClientTest.java

@@ -0,0 +1,46 @@
+package com.alibaba.dubbo.remoting.zookeeper.curator;
+
+import com.alibaba.dubbo.common.URL;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * @author ken.lj
+ * @date 2017/10/16
+ */
+public class CuratorZookeeperClientTest {
+
+    @Test
+    public void testCheckExists() {
+        CuratorZookeeperClient curatorClient = new CuratorZookeeperClient(URL.valueOf("zookeeper://127.0.0.1:2181/com.alibaba.dubbo.registry.RegistryService"));
+        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers";
+        curatorClient.create(path, false);
+        Assert.assertTrue(curatorClient.checkExists(path));
+        Assert.assertFalse(curatorClient.checkExists(path + "/noneexits"));
+    }
+
+    /**
+     * create checkExists 性能測試
+     */
+    @Test
+    public void testCreate() {
+        CuratorZookeeperClient curatorClient = new CuratorZookeeperClient(URL.valueOf("zookeeper://127.0.0.1:2181/com.alibaba.dubbo.registry.RegistryService"));
+        String path = "/dubbo/com.alibaba.dubbo.demo.DemoService/providers";
+        curatorClient.create(path, false);
+
+        // 重复create 100次，耗时
+        long startTime = System.nanoTime();
+        for (int i = 0; i < 100; i++) {
+            curatorClient.create(path, true);
+        }
+        System.out.println("create cost: " + (System.nanoTime() - startTime) / 1000 / 1000);
+
+        // 判断100次，耗时
+        startTime = System.nanoTime();
+        for (int i = 0; i < 100; i++) {
+            curatorClient.checkExists(path);
+        }
+        System.out.println("judge cost: " + (System.nanoTime() - startTime) / 1000 / 1000);
+    }
+}